diff options
Diffstat (limited to 'Documentation')
57 files changed, 3236 insertions, 247 deletions
diff --git a/Documentation/Makefile b/Documentation/Makefile index 037220f544..4797b2dc35 100644 --- a/Documentation/Makefile +++ b/Documentation/Makefile @@ -17,6 +17,7 @@ DOC_HTML=$(MAN_HTML) ARTICLES = howto-index ARTICLES += everyday ARTICLES += git-tools +ARTICLES += git-bisect-lk2009 # with their own formatting rules. SP_ARTICLES = howto/revert-branch-rebase howto/using-merge-subtree user-manual API_DOCS = $(patsubst %.txt,%,$(filter-out technical/api-index-skel.txt technical/api-index.txt, $(wildcard technical/api-*.txt))) diff --git a/Documentation/RelNotes-1.6.6.txt b/Documentation/RelNotes-1.6.6.txt new file mode 100644 index 0000000000..059e9c3c14 --- /dev/null +++ b/Documentation/RelNotes-1.6.6.txt @@ -0,0 +1,230 @@ +Git v1.6.6 Release Notes +======================== + +Notes on behaviour change +------------------------- + + * In this release, "git fsck" defaults to "git fsck --full" and + checks packfiles, and because of this it will take much longer to + complete than before. If you prefer a quicker check only on loose + objects (the old default), you can say "git fsck --no-full". This + has been supported by 1.5.4 and newer versions of git, so it is + safe to write it in your script even if you use slightly older git + on some of your machines. + +Preparing yourselves for compatibility issues in 1.7.0 +------------------------------------------------------ + +In git 1.7.0, which is planned to be the release after 1.6.6, there will +be a handful of behaviour changes that will break backward compatibility. + +These changes were discussed long time ago and existing behaviours have +been identified as more problematic to the userbase than keeping them for +the sake of backward compatibility. + +When necessary, transition strategy for existing users has been designed +not to force them running around setting configuration variables and +updating their scripts in order to either keep the traditional behaviour +or adjust to the new behaviour on the day their sysadmin decides to install +the new version of git. When we switched from "git-foo" to "git foo" in +1.6.0, even though the change had been advertised and the transition +guide had been provided for a very long time, the users procrastinated +during the entire transtion period, and ended up panicking on the day +their sysadmins updated their git installation. We are trying to avoid +repeating that unpleasantness in the 1.7.0 release. + +For changes decided to be in 1.7.0, commands that will be affected +have been much louder to strongly discourage such procrastination. If +you have been using recent versions of git, you would have seen +warnings issued when you exercised features whose behaviour will +change, with a clear instruction on how to keep the existing behaviour +if you want to. You hopefully are already well prepared. + +Of course, we have also been giving "this and that will change in +1.7.0; prepare yourselves" warnings in the release notes and +announcement messages for the past few releases. Let's see how well +users will fare this time. + + * "git push" into a branch that is currently checked out (i.e. pointed by + HEAD in a repository that is not bare) will be refused by default. + + Similarly, "git push $there :$killed" to delete the branch $killed + in a remote repository $there, when $killed branch is the current + branch pointed at by its HEAD, will be refused by default. + + Setting the configuration variables receive.denyCurrentBranch and + receive.denyDeleteCurrent to 'ignore' in the receiving repository + can be used to override these safety features. Versions of git + since 1.6.2 have issued a loud warning when you tried to do these + operations without setting the configuration, so repositories of + people who still need to be able to perform such a push should + already have been future proofed. + + Please refer to: + + http://git.or.cz/gitwiki/GitFaq#non-bare + http://thread.gmane.org/gmane.comp.version-control.git/107758/focus=108007 + + for more details on the reason why this change is needed and the + transition process that already took place so far. + + * "git send-email" will not make deep threads by default when sending a + patch series with more than two messages. All messages will be sent + as a reply to the first message, i.e. cover letter. Git 1.6.6 (this + release) will issue a warning about the upcoming default change, when + it uses the traditional "deep threading" behaviour as the built-in + default. To squelch the warning but still use the "deep threading" + behaviour, give --chain-reply-to option or set sendemail.chainreplyto + to true. + + It has been possible to configure send-email to send "shallow thread" + by setting sendemail.chainreplyto configuration variable to false. + The only thing 1.7.0 release will do is to change the default when + you haven't configured that variable. + + * "git status" will not be "git commit --dry-run". This change does not + affect you if you run the command without pathspec. + + Nobody sane found the current behaviour of "git status Makefile" useful + nor meaningful, and it confused users. "git commit --dry-run" has been + provided as a way to get the current behaviour of this command since + 1.6.5. + + * "git diff" traditionally treated various "ignore whitespace" options + only as a way to filter the patch output. "git diff --exit-code -b" + exited with non-zero status even if all changes were about changing the + ammount of whitespace and nothing else. and "git diff -b" showed the + "diff --git" header line for such a change without patch text. + + In 1.7.0, the "ignore whitespaces" will affect the semantics of the + diff operation itself. A change that does not affect anything but + whitespaces will be reported with zero exit status when run with + --exit-code, and there will not be "diff --git" header for such a + change. + + +Updates since v1.6.5 +-------------------- + +(subsystems) + + * various gitk updates including use of themed widgets under Tk 8.5, + Japanese translation, a fix to a bug when running "gui blame" from + a subdirectory, etc. + + * various git-gui updates including new translations, wm states fixes, + Tk bug workaround after quitting, improved heuristics to trigger gc, + etc. + + * various git-svn updates. + + * "git fetch" over http learned a new mode that is different from the + traditional "dumb commit walker". + +(portability) + + * imap-send can be built on mingw port. + +(performance) + + * "git diff -B" has smaller memory footprint. + +(usability, bells and whistles) + + * The object replace mechanism can be bypassed with --no-replace-objects + global option given to the "git" program. + + * In configuration files, a few variables that name paths can begin with ~/ + and ~username/ and they are expanded as expected. + + * "git subcmd -h" now shows short usage help for many more subcommands. + + * "git bisect reset" can reset to an arbitrary commit. + + * "git checkout frotz" when there is no local branch "frotz" but there + is only one remote tracking branch "frotz" is taken as a request to + start the named branch at the corresponding remote tracking branch. + + * "git commit -c/-C/--amend" can be told with a new "--reset-author" option + to ignore authorship information in the commit it is taking the message + from. + + * "git describe" can be told to add "-dirty" suffix with "--dirty" option. + + * "git diff" learned --submodule option to show a list of one-line logs + instead of differences between the commit object names. + + * "git diff" learned to honor diff.color.func configuration to paint + function name hint printed on the hunk header "@@ -j,k +l,m @@" line + in the specified color. + + * "git fetch" learned --all and --multiple options, to run fetch from + many repositories, and --prune option to remove remote tracking + branches that went stale. These make "git remote update" and "git + remote prune" less necessary (there is no plan to remove "remote + update" nor "remote prune", though). + + * "git fsck" by default checks the packfiles (i.e. "--full" is the + default); you can turn it off with "git fsck --no-full". + + * "git grep" can use -F (fixed strings) and -i (ignore case) together. + + * import-tars contributed fast-import frontend learned more types of + compressed tarballs. + + * "git instaweb" knows how to talk with mod_cgid to apache2. + + * "git log --decorate" shows the location of HEAD as well. + + * "git log" and "git rev-list" learned to take revs and pathspecs from + the standard input with the new "--stdin" option. + + * "--pretty=format" option to "log" family of commands learned: + + . to wrap text with the "%w()" specifier. + . to show reflog information with "%g[sdD]" specifier. + + * "git notes" command to annotate existing commits. + + * "git merge" (and "git pull") learned --ff-only option to make it fail + if the merge does not result in a fast-forward. + + * "git mergetool" learned to use p4merge. + + * "git rebase -i" learned "reword" that acts like "edit" but immediately + starts an editor to tweak the log message without returning control to + the shell, which is done by "edit" to give an opportunity to tweak the + contents. + + * "git send-email" can be told with "--envelope-sender=auto" to use the + same address as "From:" address as the envelope sender address. + + * "git send-email" will issue a warning when it defaults to the + --chain-reply-to behaviour without being told by the user and + instructs to prepare for the change of the default in 1.7.0 release. + + * In "git submodule add <repository> <path>", <path> is now optional and + inferred from <repository> the same way "git clone <repository>" does. + + * "git svn" learned to read SVN 1.5+ and SVK merge tickets. + + * "gitweb" can optionally render its "blame" output incrementally (this + requires JavaScript on the client side). + + * Author names shown in gitweb output are links to search commits by the + author. + + +(developers) + +Fixes since v1.6.5 +------------------ + +All of the fixes in v1.6.5.X maintenance series are included in this +release, unless otherwise noted. + +--- +exec >/var/tmp/1 +echo O=$(git describe master) +O=v1.6.6-rc1-79-g529f8c6 +git shortlog --no-merges $O..master --not maint diff --git a/Documentation/config.txt b/Documentation/config.txt index 35e26972e9..a1e36d7e42 100644 --- a/Documentation/config.txt +++ b/Documentation/config.txt @@ -135,7 +135,11 @@ advice.*:: core.fileMode:: If false, the executable bit differences between the index and the working copy are ignored; useful on broken filesystems like FAT. - See linkgit:git-update-index[1]. True by default. + See linkgit:git-update-index[1]. ++ +The default is true, except linkgit:git-clone[1] or linkgit:git-init[1] +will probe and set core.fileMode false if appropriate when the +repository is created. core.ignoreCygwinFSTricks:: This option is only used by Cygwin implementation of Git. If false, @@ -148,6 +152,18 @@ core.ignoreCygwinFSTricks:: is true, in which case ignoreCygwinFSTricks is ignored as Cygwin's POSIX emulation is required to support core.filemode. +core.ignorecase:: + If true, this option enables various workarounds to enable + git to work better on filesystems that are not case sensitive, + like FAT. For example, if a directory listing finds + "makefile" when git expects "Makefile", git will assume + it is really the same file, and continue to remember it as + "Makefile". ++ +The default is false, except linkgit:git-clone[1] or linkgit:git-init[1] +will probe and set core.ignorecase true if appropriate when the repository +is created. + core.trustctime:: If false, the ctime differences between the index and the working copy are ignored; useful when the inode change time @@ -228,7 +244,11 @@ core.symlinks:: contain the link text. linkgit:git-update-index[1] and linkgit:git-add[1] will not change the recorded type to regular file. Useful on filesystems like FAT that do not support - symbolic links. True by default. + symbolic links. ++ +The default is true, except linkgit:git-clone[1] or linkgit:git-init[1] +will probe and set core.symlinks false if appropriate when the repository +is created. core.gitProxy:: A "proxy command" to execute (as 'command host port') instead @@ -393,9 +413,7 @@ core.editor:: Commands such as `commit` and `tag` that lets you edit messages by launching an editor uses the value of this variable when it is set, and the environment variable - `GIT_EDITOR` is not set. The order of preference is - `GIT_EDITOR` environment, `core.editor`, `VISUAL` and - `EDITOR` environment variables and then finally `vi`. + `GIT_EDITOR` is not set. See linkgit:git-var[1]. core.pager:: The command that git will use to paginate output. Can @@ -464,6 +482,19 @@ On some file system/operating system combinations, this is unreliable. Set this config setting to 'rename' there; However, This will remove the check that makes sure that existing object files will not get overwritten. +core.notesRef:: + When showing commit messages, also show notes which are stored in + the given ref. This ref is expected to contain files named + after the full SHA-1 of the commit they annotate. ++ +If such a file exists in the given ref, the referenced blob is read, and +appended to the commit message, separated by a "Notes:" line. If the +given ref itself does not exist, it is not an error, but means that no +notes should be printed. ++ +This setting defaults to "refs/notes/commits", and can be overridden by +the `GIT_NOTES_REF` environment variable. + add.ignore-errors:: Tells 'git-add' to continue adding files when some files cannot be added due to indexing errors. Equivalent to the '--ignore-errors' @@ -604,10 +635,10 @@ color.diff.<slot>:: Use customized color for diff colorization. `<slot>` specifies which part of the patch to use the specified color, and is one of `plain` (context text), `meta` (metainformation), `frag` - (hunk header), `old` (removed lines), `new` (added lines), - `commit` (commit headers), or `whitespace` (highlighting - whitespace errors). The values of these variables may be specified as - in color.branch.<slot>. + (hunk header), 'func' (function in hunk header), `old` (removed lines), + `new` (added lines), `commit` (commit headers), or `whitespace` + (highlighting whitespace errors). The values of these variables may be + specified as in color.branch.<slot>. color.grep:: When set to `always`, always highlight matches. When `false` (or @@ -1101,6 +1132,14 @@ http.maxRequests:: How many HTTP requests to launch in parallel. Can be overridden by the 'GIT_HTTP_MAX_REQUESTS' environment variable. Default is 5. +http.postBuffer:: + Maximum size in bytes of the buffer used by smart HTTP + transports when POSTing data to the remote system. + For requests larger than this buffer size, HTTP/1.1 and + Transfer-Encoding: chunked is used to avoid creating a + massive pack file locally. Default is 1 MiB, which is + sufficient for most requests. + http.lowSpeedLimit, http.lowSpeedTime:: If the HTTP transfer speed is less than 'http.lowSpeedLimit' for longer than 'http.lowSpeedTime' seconds, the transfer is aborted. @@ -1368,7 +1407,7 @@ receive.denyCurrentBranch:: receive.denyNonFastForwards:: If set to true, git-receive-pack will deny a ref update which is - not a fast forward. Use this to prevent such an update via a push, + not a fast-forward. Use this to prevent such an update via a push, even if that push is forced. This configuration variable is set when initializing a shared repository. @@ -1402,7 +1441,13 @@ remote.<name>.mirror:: remote.<name>.skipDefaultUpdate:: If true, this remote will be skipped by default when updating - using the update subcommand of linkgit:git-remote[1]. + using linkgit:git-fetch[1] or the `update` subcommand of + linkgit:git-remote[1]. + +remote.<name>.skipFetchAll:: + If true, this remote will be skipped by default when updating + using linkgit:git-fetch[1] or the `update` subcommand of + linkgit:git-remote[1]. remote.<name>.receivepack:: The default program to execute on the remote side when pushing. See diff --git a/Documentation/diff-options.txt b/Documentation/diff-options.txt index 9276faeb11..8707d0e740 100644 --- a/Documentation/diff-options.txt +++ b/Documentation/diff-options.txt @@ -14,7 +14,8 @@ endif::git-format-patch[] ifdef::git-format-patch[] -p:: - Generate patches without diffstat. +--no-stat:: + Generate plain patches without any diffstats. endif::git-format-patch[] ifndef::git-format-patch[] @@ -27,33 +28,40 @@ endif::git-format-patch[] -U<n>:: --unified=<n>:: Generate diffs with <n> lines of context instead of - the usual three. Implies "-p". + the usual three. +ifndef::git-format-patch[] + Implies `-p`. +endif::git-format-patch[] +ifndef::git-format-patch[] --raw:: Generate the raw format. {git-diff-core? This is the default.} +endif::git-format-patch[] +ifndef::git-format-patch[] --patch-with-raw:: - Synonym for "-p --raw". + Synonym for `-p --raw`. +endif::git-format-patch[] --patience:: Generate a diff using the "patience diff" algorithm. --stat[=width[,name-width]]:: Generate a diffstat. You can override the default - output width for 80-column terminal by "--stat=width". + output width for 80-column terminal by `--stat=width`. The width of the filename part can be controlled by giving another width to it separated by a comma. --numstat:: - Similar to \--stat, but shows number of added and + Similar to `\--stat`, but shows number of added and deleted lines in decimal notation and pathname without abbreviation, to make it more machine friendly. For binary files, outputs two `-` instead of saying `0 0`. --shortstat:: - Output only the last line of the --stat format containing total + Output only the last line of the `--stat` format containing total number of modified files, as well as number of added and deleted lines. @@ -61,24 +69,39 @@ endif::git-format-patch[] Output the distribution of relative amount of changes (number of lines added or removed) for each sub-directory. Directories with changes below a cut-off percent (3% by default) are not shown. The cut-off percent - can be set with "--dirstat=limit". Changes in a child directory is not - counted for the parent directory, unless "--cumulative" is used. + can be set with `--dirstat=limit`. Changes in a child directory is not + counted for the parent directory, unless `--cumulative` is used. --dirstat-by-file[=limit]:: - Same as --dirstat, but counts changed files instead of lines. + Same as `--dirstat`, but counts changed files instead of lines. --summary:: Output a condensed summary of extended header information such as creations, renames and mode changes. +ifndef::git-format-patch[] --patch-with-stat:: - Synonym for "-p --stat". - {git-format-patch? This is the default.} + Synonym for `-p --stat`. +endif::git-format-patch[] + +ifndef::git-format-patch[] -z:: - NUL-line termination on output. This affects the --raw - output field terminator. Also output from commands such - as "git-log" will be delimited with NUL between commits. +ifdef::git-log[] + Separate the commits with NULs instead of with new newlines. ++ +Also, when `--raw` or `--numstat` has been given, do not munge +pathnames and use NULs as output field terminators. +endif::git-log[] +ifndef::git-log[] + When `--raw` or `--numstat` has been given, do not munge + pathnames and use NULs as output field terminators. +endif::git-log[] ++ +Without this option, each pathname output will have TAB, LF, double quotes, +and backslash characters replaced with `\t`, `\n`, `\"`, and `\\`, +respectively, and the pathname will be enclosed in double quotes if +any of those replacements occurred. --name-only:: Show only names of changed files. @@ -87,6 +110,13 @@ endif::git-format-patch[] Show only names and status of changed files. See the description of the `--diff-filter` option on what the status letters mean. +--submodule[=<format>]:: + Chose the output format for submodule differences. <format> can be one of + 'short' and 'log'. 'short' just shows pairs of commit names, this format + is used when this option is not given. 'log' is the default value for this + option and lists the commits in that commit range like the 'summary' + option of linkgit:git-submodule[1] does. + --color:: Show colored diff. @@ -110,16 +140,19 @@ The regex can also be set via a diff driver or configuration option, see linkgit:gitattributes[1] or linkgit:git-config[1]. Giving it explicitly overrides any diff driver or configuration setting. Diff drivers override configuration settings. +endif::git-format-patch[] --no-renames:: Turn off rename detection, even when the configuration file gives the default to do so. +ifndef::git-format-patch[] --check:: Warn if changes introduce trailing whitespace or an indent that uses a space before a tab. Exits with non-zero status if problems are found. Not compatible with --exit-code. +endif::git-format-patch[] --full-index:: Instead of the first handful of characters, show the full @@ -127,16 +160,16 @@ override configuration settings. line when generating patch format output. --binary:: - In addition to --full-index, output "binary diff" that - can be applied with "git apply". + In addition to `--full-index`, output a binary diff that + can be applied with `git-apply`. --abbrev[=<n>]:: Instead of showing the full 40-byte hexadecimal object name in diff-raw format output and diff-tree header lines, show only a partial prefix. This is - independent of --full-index option above, which controls + independent of the `--full-index` option above, which controls the diff-patch output format. Non default number of - digits can be specified with --abbrev=<n>. + digits can be specified with `--abbrev=<n>`. -B:: Break complete rewrite changes into pairs of delete and create. @@ -147,6 +180,7 @@ override configuration settings. -C:: Detect copies as well as renames. See also `--find-copies-harder`. +ifndef::git-format-patch[] --diff-filter=[ACDMRTUXB*]:: Select only files that are Added (`A`), Copied (`C`), Deleted (`D`), Modified (`M`), Renamed (`R`), have their @@ -158,6 +192,7 @@ override configuration settings. paths are selected if there is any file that matches other criteria in the comparison; if there is no file that matches other criteria, nothing is selected. +endif::git-format-patch[] --find-copies-harder:: For performance reasons, by default, `-C` option finds copies only @@ -169,12 +204,13 @@ override configuration settings. `-C` option has the same effect. -l<num>:: - -M and -C options require O(n^2) processing time where n + The `-M` and `-C` options require O(n^2) processing time where n is the number of potential rename/copy targets. This option prevents rename/copy detection from running if the number of rename/copy targets exceeds the specified number. +ifndef::git-format-patch[] -S<string>:: Look for differences that introduce or remove an instance of <string>. Note that this is different than the string simply @@ -182,18 +218,20 @@ override configuration settings. linkgit:gitdiffcore[7] for more details. --pickaxe-all:: - When -S finds a change, show all the changes in that + When `-S` finds a change, show all the changes in that changeset, not just the files that contain the change in <string>. --pickaxe-regex:: Make the <string> not a plain string but an extended POSIX regex to match. +endif::git-format-patch[] -O<orderfile>:: Output the patch in the order specified in the <orderfile>, which has one shell glob pattern per line. +ifndef::git-format-patch[] -R:: Swap two inputs; that is, show differences from index or on-disk file to tree contents. @@ -205,6 +243,7 @@ override configuration settings. not in a subdirectory (e.g. in a bare repository), you can name which subdirectory to make the output relative to by giving a <path> as an argument. +endif::git-format-patch[] -a:: --text:: @@ -229,13 +268,15 @@ override configuration settings. Show the context between diff hunks, up to the specified number of lines, thereby fusing hunks that are close to each other. +ifndef::git-format-patch[] --exit-code:: Make the program exit with codes similar to diff(1). That is, it exits with 1 if there were differences and 0 means no differences. --quiet:: - Disable all output of the program. Implies --exit-code. + Disable all output of the program. Implies `--exit-code`. +endif::git-format-patch[] --ext-diff:: Allow an external diff helper to be executed. If you set an diff --git a/Documentation/fetch-options.txt b/Documentation/fetch-options.txt index 28868747da..ab6419fe6e 100644 --- a/Documentation/fetch-options.txt +++ b/Documentation/fetch-options.txt @@ -1,3 +1,6 @@ +--all:: + Fetch all remotes. + -a:: --append:: Append ref names and object names of fetched refs to the @@ -9,6 +12,11 @@ `git clone` with `--depth=<depth>` option (see linkgit:git-clone[1]) by the specified number of commits. +ifndef::git-pull[] +--dry-run:: + Show what would be done, without making any changes. +endif::git-pull[] + -f:: --force:: When 'git-fetch' is used with `<rbranch>:<lbranch>` @@ -21,6 +29,16 @@ --keep:: Keep downloaded pack. +ifndef::git-pull[] +--multiple:: + Allow several <repository> and <group> arguments to be + specified. No <refspec>s may be specified. + +--prune:: + After fetching, remove any remote tracking branches which + no longer exist on the remote. +endif::git-pull[] + ifdef::git-pull[] --no-tags:: endif::git-pull[] diff --git a/Documentation/git-apply.txt b/Documentation/git-apply.txt index 5ee8c91f2d..c2528a7654 100644 --- a/Documentation/git-apply.txt +++ b/Documentation/git-apply.txt @@ -3,7 +3,7 @@ git-apply(1) NAME ---- -git-apply - Apply a patch on a git index file and/or a working tree +git-apply - Apply a patch to files and/or to the index SYNOPSIS @@ -20,8 +20,11 @@ SYNOPSIS DESCRIPTION ----------- -Reads supplied 'diff' output and applies it on a git index file -and a work tree. +Reads the supplied diff output (i.e. "a patch") and applies it to files. +With the `--index` option the patch is also applied to the index, and +with the `--cache` option the patch is only applied to the index. +Without these options, the command applies the patch only to files, +and does not require them to be in a git repository. OPTIONS ------- @@ -34,7 +37,7 @@ OPTIONS input. Turns off "apply". --numstat:: - Similar to \--stat, but shows the number of added and + Similar to `--stat`, but shows the number of added and deleted lines in decimal notation and the pathname without abbreviation, to make it more machine friendly. For binary files, outputs two `-` instead of saying @@ -48,22 +51,22 @@ OPTIONS --check:: Instead of applying the patch, see if the patch is - applicable to the current work tree and/or the index + applicable to the current working tree and/or the index file and detects errors. Turns off "apply". --index:: - When --check is in effect, or when applying the patch + When `--check` is in effect, or when applying the patch (which is the default when none of the options that disables it is in effect), make sure the patch is applicable to what the current index file records. If - the file to be patched in the work tree is not + the file to be patched in the working tree is not up-to-date, it is flagged as an error. This flag also causes the index file to be updated. --cached:: Apply a patch without touching the working tree. Instead take the cached data, apply the patch, and store the result in the index - without using the working tree. This implies '--index'. + without using the working tree. This implies `--index`. --build-fake-ancestor=<file>:: Newer 'git-diff' output has embedded 'index information' @@ -87,11 +90,13 @@ the information is read from the current index instead. rejected hunks in corresponding *.rej files. -z:: - When showing the index information, do not munge paths, - but use NUL terminated machine readable format. Without - this flag, the pathnames output will have TAB, LF, and - backslash characters replaced with `\t`, `\n`, and `\\`, - respectively. + When `--numstat` has been given, do not munge pathnames, + but use a NUL-terminated machine-readable format. ++ +Without this option, each pathname output will have TAB, LF, double quotes, +and backslash characters replaced with `\t`, `\n`, `\"`, and `\\`, +respectively, and the pathname will be enclosed in double quotes if +any of those replacements occurred. -p<n>:: Remove <n> leading slashes from traditional diff paths. The @@ -107,8 +112,8 @@ the information is read from the current index instead. By default, 'git-apply' expects that the patch being applied is a unified diff with at least one line of context. This provides good safety measures, but breaks down when - applying a diff generated with --unified=0. To bypass these - checks use '--unidiff-zero'. + applying a diff generated with `--unified=0`. To bypass these + checks use `--unidiff-zero`. + Note, for the reasons stated above usage of context-free patches is discouraged. @@ -144,7 +149,7 @@ discouraged. be useful when importing patchsets, where you want to include certain files or directories. + -When --exclude and --include patterns are used, they are examined in the +When `--exclude` and `--include` patterns are used, they are examined in the order they appear on the command line, and the first match determines if a patch to each path is used. A patch to a path that does not match any include/exclude pattern is used by default if there is no include pattern @@ -227,13 +232,13 @@ Submodules If the patch contains any changes to submodules then 'git-apply' treats these changes as follows. -If --index is specified (explicitly or implicitly), then the submodule +If `--index` is specified (explicitly or implicitly), then the submodule commits must match the index exactly for the patch to apply. If any of the submodules are checked-out, then these check-outs are completely ignored, i.e., they are not required to be up-to-date or clean and they are not updated. -If --index is not specified, then the submodule commits in the patch +If `--index` is not specified, then the submodule commits in the patch are ignored and only the absence or presence of the corresponding subdirectory is checked and (if possible) updated. diff --git a/Documentation/git-bisect-lk2009.txt b/Documentation/git-bisect-lk2009.txt new file mode 100644 index 0000000000..6b7b2e5497 --- /dev/null +++ b/Documentation/git-bisect-lk2009.txt @@ -0,0 +1,1358 @@ +Fighting regressions with git bisect +==================================== +:Author: Christian Couder +:Email: chriscool@tuxfamily.org +:Date: 2009/11/08 + +Abstract +-------- + +"git bisect" enables software users and developers to easily find the +commit that introduced a regression. We show why it is important to +have good tools to fight regressions. We describe how "git bisect" +works from the outside and the algorithms it uses inside. Then we +explain how to take advantage of "git bisect" to improve current +practices. And we discuss how "git bisect" could improve in the +future. + + +Introduction to "git bisect" +---------------------------- + +Git is a Distributed Version Control system (DVCS) created by Linus +Torvalds and maintained by Junio Hamano. + +In Git like in many other Version Control Systems (VCS), the different +states of the data that is managed by the system are called +commits. And, as VCS are mostly used to manage software source code, +sometimes "interesting" changes of behavior in the software are +introduced in some commits. + +In fact people are specially interested in commits that introduce a +"bad" behavior, called a bug or a regression. They are interested in +these commits because a commit (hopefully) contains a very small set +of source code changes. And it's much easier to understand and +properly fix a problem when you only need to check a very small set of +changes, than when you don't know where look in the first place. + +So to help people find commits that introduce a "bad" behavior, the +"git bisect" set of commands was invented. And it follows of course +that in "git bisect" parlance, commits where the "interesting +behavior" is present are called "bad" commits, while other commits are +called "good" commits. And a commit that introduce the behavior we are +interested in is called a "first bad commit". Note that there could be +more than one "first bad commit" in the commit space we are searching. + +So "git bisect" is designed to help find a "first bad commit". And to +be as efficient as possible, it tries to perform a binary search. + + +Fighting regressions overview +----------------------------- + +Regressions: a big problem +~~~~~~~~~~~~~~~~~~~~~~~~~~ + +Regressions are a big problem in the software industry. But it's +difficult to put some real numbers behind that claim. + +There are some numbers about bugs in general, like a NIST study in +2002 <<1>> that said: + +_____________ +Software bugs, or errors, are so prevalent and so detrimental that +they cost the U.S. economy an estimated $59.5 billion annually, or +about 0.6 percent of the gross domestic product, according to a newly +released study commissioned by the Department of Commerce's National +Institute of Standards and Technology (NIST). At the national level, +over half of the costs are borne by software users and the remainder +by software developers/vendors. The study also found that, although +all errors cannot be removed, more than a third of these costs, or an +estimated $22.2 billion, could be eliminated by an improved testing +infrastructure that enables earlier and more effective identification +and removal of software defects. These are the savings associated with +finding an increased percentage (but not 100 percent) of errors closer +to the development stages in which they are introduced. Currently, +over half of all errors are not found until "downstream" in the +development process or during post-sale software use. +_____________ + +And then: + +_____________ +Software developers already spend approximately 80 percent of +development costs on identifying and correcting defects, and yet few +products of any type other than software are shipped with such high +levels of errors. +_____________ + +Eventually the conclusion started with: + +_____________ +The path to higher software quality is significantly improved software +testing. +_____________ + +There are other estimates saying that 80% of the cost related to +software is about maintenance <<2>>. + +Though, according to Wikipedia <<3>>: + +_____________ +A common perception of maintenance is that it is merely fixing +bugs. However, studies and surveys over the years have indicated that +the majority, over 80%, of the maintenance effort is used for +non-corrective actions (Pigosky 1997). This perception is perpetuated +by users submitting problem reports that in reality are functionality +enhancements to the system. +_____________ + +But we can guess that improving on existing software is very costly +because you have to watch out for regressions. At least this would +make the above studies consistent among themselves. + +Of course some kind of software is developed, then used during some +time without being improved on much, and then finally thrown away. In +this case, of course, regressions may not be a big problem. But on the +other hand, there is a lot of big software that is continually +developed and maintained during years or even tens of years by a lot +of people. And as there are often many people who depend (sometimes +critically) on such software, regressions are a really big problem. + +One such software is the linux kernel. And if we look at the linux +kernel, we can see that a lot of time and effort is spent to fight +regressions. The release cycle start with a 2 weeks long merge +window. Then the first release candidate (rc) version is tagged. And +after that about 7 or 8 more rc versions will appear with around one +week between each of them, before the final release. + +The time between the first rc release and the final release is +supposed to be used to test rc versions and fight bugs and especially +regressions. And this time is more than 80% of the release cycle +time. But this is not the end of the fight yet, as of course it +continues after the release. + +And then this is what Ingo Molnar (a well known linux kernel +developer) says about his use of git bisect: + +_____________ +I most actively use it during the merge window (when a lot of trees +get merged upstream and when the influx of bugs is the highest) - and +yes, there have been cases that i used it multiple times a day. My +average is roughly once a day. +_____________ + +So regressions are fought all the time by developers, and indeed it is +well known that bugs should be fixed as soon as possible, so as soon +as they are found. That's why it is interesting to have good tools for +this purpose. + +Other tools to fight regressions +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + +So what are the tools used to fight regressions? They are nearly the +same as those used to fight regular bugs. The only specific tools are +test suites and tools similar as "git bisect". + +Test suites are very nice. But when they are used alone, they are +supposed to be used so that all the tests are checked after each +commit. This means that they are not very efficient, because many +tests are run for no interesting result, and they suffer from +combinational explosion. + +In fact the problem is that big software often has many different +configuration options and that each test case should pass for each +configuration after each commit. So if you have for each release: N +configurations, M commits and T test cases, you should perform: + +------------- +N * M * T tests +------------- + +where N, M and T are all growing with the size your software. + +So very soon it will not be possible to completely test everything. + +And if some bugs slip through your test suite, then you can add a test +to your test suite. But if you want to use your new improved test +suite to find where the bug slipped in, then you will either have to +emulate a bisection process or you will perhaps bluntly test each +commit backward starting from the "bad" commit you have which may be +very wasteful. + +"git bisect" overview +--------------------- + +Starting a bisection +~~~~~~~~~~~~~~~~~~~~ + +The first "git bisect" subcommand to use is "git bisect start" to +start the search. Then bounds must be set to limit the commit +space. This is done usually by giving one "bad" and at least one +"good" commit. They can be passed in the initial call to "git bisect +start" like this: + +------------- +$ git bisect start [BAD [GOOD...]] +------------- + +or they can be set using: + +------------- +$ git bisect bad [COMMIT] +------------- + +and: + +------------- +$ git bisect good [COMMIT...] +------------- + +where BAD, GOOD and COMMIT are all names that can be resolved to a +commit. + +Then "git bisect" will checkout a commit of its choosing and ask the +user to test it, like this: + +------------- +$ git bisect start v2.6.27 v2.6.25 +Bisecting: 10928 revisions left to test after this (roughly 14 steps) +[2ec65f8b89ea003c27ff7723525a2ee335a2b393] x86: clean up using max_low_pfn on 32-bit +------------- + +Note that the example that we will use is really a toy example, we +will be looking for the first commit that has a version like +"2.6.26-something", that is the commit that has a "SUBLEVEL = 26" line +in the top level Makefile. This is a toy example because there are +better ways to find this commit with git than using "git bisect" (for +example "git blame" or "git log -S<string>"). + +Driving a bisection manually +~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + +At this point there are basically 2 ways to drive the search. It can +be driven manually by the user or it can be driven automatically by a +script or a command. + +If the user is driving it, then at each step of the search, the user +will have to test the current commit and say if it is "good" or "bad" +using the "git bisect good" or "git bisect bad" commands respectively +that have been described above. For example: + +------------- +$ git bisect bad +Bisecting: 5480 revisions left to test after this (roughly 13 steps) +[66c0b394f08fd89236515c1c84485ea712a157be] KVM: kill file->f_count abuse in kvm +------------- + +And after a few more steps like that, "git bisect" will eventually +find a first bad commit: + +------------- +$ git bisect bad +2ddcca36c8bcfa251724fe342c8327451988be0d is the first bad commit +commit 2ddcca36c8bcfa251724fe342c8327451988be0d +Author: Linus Torvalds <torvalds@linux-foundation.org> +Date: Sat May 3 11:59:44 2008 -0700 + + Linux 2.6.26-rc1 + +:100644 100644 5cf8258195331a4dbdddff08b8d68642638eea57 4492984efc09ab72ff6219a7bc21fb6a957c4cd5 M Makefile +------------- + +At this point we can see what the commit does, check it out (if it's +not already checked out) or tinker with it, for example: + +------------- +$ git show HEAD +commit 2ddcca36c8bcfa251724fe342c8327451988be0d +Author: Linus Torvalds <torvalds@linux-foundation.org> +Date: Sat May 3 11:59:44 2008 -0700 + + Linux 2.6.26-rc1 + +diff --git a/Makefile b/Makefile +index 5cf8258..4492984 100644 +--- a/Makefile ++++ b/Makefile +@@ -1,7 +1,7 @@ + VERSION = 2 + PATCHLEVEL = 6 +-SUBLEVEL = 25 +-EXTRAVERSION = ++SUBLEVEL = 26 ++EXTRAVERSION = -rc1 + NAME = Funky Weasel is Jiggy wit it + + # *DOCUMENTATION* +------------- + +And when we are finished we can use "git bisect reset" to go back to +the branch we were in before we started bisecting: + +------------- +$ git bisect reset +Checking out files: 100% (21549/21549), done. +Previous HEAD position was 2ddcca3... Linux 2.6.26-rc1 +Switched to branch 'master' +------------- + +Driving a bisection automatically +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + +The other way to drive the bisection process is to tell "git bisect" +to launch a script or command at each bisection step to know if the +current commit is "good" or "bad". To do that, we use the "git bisect +run" command. For example: + +------------- +$ git bisect start v2.6.27 v2.6.25 +Bisecting: 10928 revisions left to test after this (roughly 14 steps) +[2ec65f8b89ea003c27ff7723525a2ee335a2b393] x86: clean up using max_low_pfn on 32-bit +$ +$ git bisect run grep '^SUBLEVEL = 25' Makefile +running grep ^SUBLEVEL = 25 Makefile +Bisecting: 5480 revisions left to test after this (roughly 13 steps) +[66c0b394f08fd89236515c1c84485ea712a157be] KVM: kill file->f_count abuse in kvm +running grep ^SUBLEVEL = 25 Makefile +SUBLEVEL = 25 +Bisecting: 2740 revisions left to test after this (roughly 12 steps) +[671294719628f1671faefd4882764886f8ad08cb] V4L/DVB(7879): Adding cx18 Support for mxl5005s +... +... +running grep ^SUBLEVEL = 25 Makefile +Bisecting: 0 revisions left to test after this (roughly 0 steps) +[2ddcca36c8bcfa251724fe342c8327451988be0d] Linux 2.6.26-rc1 +running grep ^SUBLEVEL = 25 Makefile +2ddcca36c8bcfa251724fe342c8327451988be0d is the first bad commit +commit 2ddcca36c8bcfa251724fe342c8327451988be0d +Author: Linus Torvalds <torvalds@linux-foundation.org> +Date: Sat May 3 11:59:44 2008 -0700 + + Linux 2.6.26-rc1 + +:100644 100644 5cf8258195331a4dbdddff08b8d68642638eea57 4492984efc09ab72ff6219a7bc21fb6a957c4cd5 M Makefile +bisect run success +------------- + +In this example, we passed "grep '^SUBLEVEL = 25' Makefile" as +parameter to "git bisect run". This means that at each step, the grep +command we passed will be launched. And if it exits with code 0 (that +means success) then git bisect will mark the current state as +"good". If it exits with code 1 (or any code between 1 and 127 +included, except the special code 125), then the current state will be +marked as "bad". + +Exit code between 128 and 255 are special to "git bisect run". They +make it stop immediately the bisection process. This is useful for +example if the command passed takes too long to complete, because you +can kill it with a signal and it will stop the bisection process. + +It can also be useful in scripts passed to "git bisect run" to "exit +255" if some very abnormal situation is detected. + +Avoiding untestable commits +~~~~~~~~~~~~~~~~~~~~~~~~~~~ + +Sometimes it happens that the current state cannot be tested, for +example if it does not compile because there was a bug preventing it +at that time. This is what the special exit code 125 is for. It tells +"git bisect run" that the current commit should be marked as +untestable and that another one should be chosen and checked out. + +If the bisection process is driven manually, you can use "git bisect +skip" to do the same thing. (In fact the special exit code 125 makes +"git bisect run" use "git bisect skip" in the background.) + +Or if you want more control, you can inspect the current state using +for example "git bisect visualize". It will launch gitk (or "git log" +if the DISPLAY environment variable is not set) to help you find a +better bisection point. + +Either way, if you have a string of untestable commits, it might +happen that the regression you are looking for has been introduced by +one of these untestable commits. In this case it's not possible to +tell for sure which commit introduced the regression. + +So if you used "git bisect skip" (or the run script exited with +special code 125) you could get a result like this: + +------------- +There are only 'skip'ped commits left to test. +The first bad commit could be any of: +15722f2fa328eaba97022898a305ffc8172db6b1 +78e86cf3e850bd755bb71831f42e200626fbd1e0 +e15b73ad3db9b48d7d1ade32f8cd23a751fe0ace +070eab2303024706f2924822bfec8b9847e4ac1b +We cannot bisect more! +------------- + +Saving a log and replaying it +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + +If you want to show other people your bisection process, you can get a +log using for example: + +------------- +$ git bisect log > bisect_log.txt +------------- + +And it is possible to replay it using: + +------------- +$ git bisect replay bisect_log.txt +------------- + + +"git bisect" details +-------------------- + +Bisection algorithm +~~~~~~~~~~~~~~~~~~~ + +As the Git commits form a directed acyclic graph (DAG), finding the +best bisection commit to test at each step is not so simple. Anyway +Linus found and implemented a "truly stupid" algorithm, later improved +by Junio Hamano, that works quite well. + +So the algorithm used by "git bisect" to find the best bisection +commit when there are no skipped commits is the following: + +1) keep only the commits that: + +a) are ancestor of the "bad" commit (including the "bad" commit itself), +b) are not ancestor of a "good" commit (excluding the "good" commits). + +This means that we get rid of the uninteresting commits in the DAG. + +For example if we start with a graph like this: + +------------- +G-Y-G-W-W-W-X-X-X-X + \ / + W-W-B + / +Y---G-W---W + \ / \ +Y-Y X-X-X-X + +-> time goes this way -> +------------- + +where B is the "bad" commit, "G" are "good" commits and W, X, and Y +are other commits, we will get the following graph after this first +step: + +------------- +W-W-W + \ + W-W-B + / +W---W +------------- + +So only the W and B commits will be kept. Because commits X and Y will +have been removed by rules a) and b) respectively, and because commits +G are removed by rule b) too. + +Note for git users, that it is equivalent as keeping only the commit +given by: + +------------- +git rev-list BAD --not GOOD1 GOOD2... +------------- + +Also note that we don't require the commits that are kept to be +descendants of a "good" commit. So in the following example, commits W +and Z will be kept: + +------------- +G-W-W-W-B + / +Z-Z +------------- + +2) starting from the "good" ends of the graph, associate to each +commit the number of ancestors it has plus one + +For example with the following graph where H is the "bad" commit and A +and D are some parents of some "good" commits: + +------------- +A-B-C + \ + F-G-H + / +D---E +------------- + +this will give: + +------------- +1 2 3 +A-B-C + \6 7 8 + F-G-H +1 2/ +D---E +------------- + +3) associate to each commit: min(X, N - X) + +where X is the value associated to the commit in step 2) and N is the +total number of commits in the graph. + +In the above example we have N = 8, so this will give: + +------------- +1 2 3 +A-B-C + \2 1 0 + F-G-H +1 2/ +D---E +------------- + +4) the best bisection point is the commit with the highest associated +number + +So in the above example the best bisection point is commit C. + +5) note that some shortcuts are implemented to speed up the algorithm + +As we know N from the beginning, we know that min(X, N - X) can't be +greater than N/2. So during steps 2) and 3), if we would associate N/2 +to a commit, then we know this is the best bisection point. So in this +case we can just stop processing any other commit and return the +current commit. + +Bisection algorithm debugging +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + +For any commit graph, you can see the number associated with each +commit using "git rev-list --bisect-all". + +For example, for the above graph, a command like: + +------------- +$ git rev-list --bisect-all BAD --not GOOD1 GOOD2 +------------- + +would output something like: + +------------- +e15b73ad3db9b48d7d1ade32f8cd23a751fe0ace (dist=3) +15722f2fa328eaba97022898a305ffc8172db6b1 (dist=2) +78e86cf3e850bd755bb71831f42e200626fbd1e0 (dist=2) +a1939d9a142de972094af4dde9a544e577ddef0e (dist=2) +070eab2303024706f2924822bfec8b9847e4ac1b (dist=1) +a3864d4f32a3bf5ed177ddef598490a08760b70d (dist=1) +a41baa717dd74f1180abf55e9341bc7a0bb9d556 (dist=1) +9e622a6dad403b71c40979743bb9d5be17b16bd6 (dist=0) +------------- + +Bisection algorithm discussed +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + +First let's define "best bisection point". We will say that a commit X +is a best bisection point or a best bisection commit if knowing its +state ("good" or "bad") gives as much information as possible whether +the state of the commit happens to be "good" or "bad". + +This means that the best bisection commits are the commits where the +following function is maximum: + +------------- +f(X) = min(information_if_good(X), information_if_bad(X)) +------------- + +where information_if_good(X) is the information we get if X is good +and information_if_bad(X) is the information we get if X is bad. + +Now we will suppose that there is only one "first bad commit". This +means that all its descendants are "bad" and all the other commits are +"good". And we will suppose that all commits have an equal probability +of being good or bad, or of being the first bad commit, so knowing the +state of c commits gives always the same amount of information +wherever these c commits are on the graph and whatever c is. (So we +suppose that these commits being for example on a branch or near a +good or a bad commit does not give more or less information). + +Let's also suppose that we have a cleaned up graph like one after step +1) in the bisection algorithm above. This means that we can measure +the information we get in terms of number of commit we can remove from +the graph.. + +And let's take a commit X in the graph. + +If X is found to be "good", then we know that its ancestors are all +"good", so we want to say that: + +------------- +information_if_good(X) = number_of_ancestors(X) (TRUE) +------------- + +And this is true because at step 1) b) we remove the ancestors of the +"good" commits. + +If X is found to be "bad", then we know that its descendants are all +"bad", so we want to say that: + +------------- +information_if_bad(X) = number_of_descendants(X) (WRONG) +------------- + +But this is wrong because at step 1) a) we keep only the ancestors of +the bad commit. So we get more information when a commit is marked as +"bad", because we also know that the ancestors of the previous "bad" +commit that are not ancestors of the new "bad" commit are not the +first bad commit. We don't know if they are good or bad, but we know +that they are not the first bad commit because they are not ancestor +of the new "bad" commit. + +So when a commit is marked as "bad" we know we can remove all the +commits in the graph except those that are ancestors of the new "bad" +commit. This means that: + +------------- +information_if_bad(X) = N - number_of_ancestors(X) (TRUE) +------------- + +where N is the number of commits in the (cleaned up) graph. + +So in the end this means that to find the best bisection commits we +should maximize the function: + +------------- +f(X) = min(number_of_ancestors(X), N - number_of_ancestors(X)) +------------- + +And this is nice because at step 2) we compute number_of_ancestors(X) +and so at step 3) we compute f(X). + +Let's take the following graph as an example: + +------------- + G-H-I-J + / \ +A-B-C-D-E-F O + \ / + K-L-M-N +------------- + +If we compute the following non optimal function on it: + +------------- +g(X) = min(number_of_ancestors(X), number_of_descendants(X)) +------------- + +we get: + +------------- + 4 3 2 1 + G-H-I-J +1 2 3 4 5 6/ \0 +A-B-C-D-E-F O + \ / + K-L-M-N + 4 3 2 1 +------------- + +but with the algorithm used by git bisect we get: + +------------- + 7 7 6 5 + G-H-I-J +1 2 3 4 5 6/ \0 +A-B-C-D-E-F O + \ / + K-L-M-N + 7 7 6 5 +------------- + +So we chose G, H, K or L as the best bisection point, which is better +than F. Because if for example L is bad, then we will know not only +that L, M and N are bad but also that G, H, I and J are not the first +bad commit (since we suppose that there is only one first bad commit +and it must be an ancestor of L). + +So the current algorithm seems to be the best possible given what we +initially supposed. + +Skip algorithm +~~~~~~~~~~~~~~ + +When some commits have been skipped (using "git bisect skip"), then +the bisection algorithm is the same for step 1) to 3). But then we use +roughly the following steps: + +6) sort the commit by decreasing associated value + +7) if the first commit has not been skipped, we can return it and stop +here + +8) otherwise filter out all the skipped commits in the sorted list + +9) use a pseudo random number generator (PRNG) to generate a random +number between 0 and 1 + +10) multiply this random number with its square root to bias it toward +0 + +11) multiply the result by the number of commits in the filtered list +to get an index into this list + +12) return the commit at the computed index + +Skip algorithm discussed +~~~~~~~~~~~~~~~~~~~~~~~~ + +After step 7) (in the skip algorithm), we could check if the second +commit has been skipped and return it if it is not the case. And in +fact that was the algorithm we used from when "git bisect skip" was +developed in git version 1.5.4 (released on February 1st 2008) until +git version 1.6.4 (released July 29th 2009). + +But Ingo Molnar and H. Peter Anvin (another well known linux kernel +developer) both complained that sometimes the best bisection points +all happened to be in an area where all the commits are +untestable. And in this case the user was asked to test many +untestable commits, which could be very inefficient. + +Indeed untestable commits are often untestable because a breakage was +introduced at one time, and that breakage was fixed only after many +other commits were introduced. + +This breakage is of course most of the time unrelated to the breakage +we are trying to locate in the commit graph. But it prevents us to +know if the interesting "bad behavior" is present or not. + +So it is a fact that commits near an untestable commit have a high +probability of being untestable themselves. And the best bisection +commits are often found together too (due to the bisection algorithm). + +This is why it is a bad idea to just chose the next best unskipped +bisection commit when the first one has been skipped. + +We found that most commits on the graph may give quite a lot of +information when they are tested. And the commits that will not on +average give a lot of information are the one near the good and bad +commits. + +So using a PRNG with a bias to favor commits away from the good and +bad commits looked like a good choice. + +One obvious improvement to this algorithm would be to look for a +commit that has an associated value near the one of the best bisection +commit, and that is on another branch, before using the PRNG. Because +if such a commit exists, then it is not very likely to be untestable +too, so it will probably give more information than a nearly randomly +chosen one. + +Checking merge bases +~~~~~~~~~~~~~~~~~~~~ + +There is another tweak in the bisection algorithm that has not been +described in the "bisection algorithm" above. + +We supposed in the previous examples that the "good" commits were +ancestors of the "bad" commit. But this is not a requirement of "git +bisect". + +Of course the "bad" commit cannot be an ancestor of a "good" commit, +because the ancestors of the good commits are supposed to be +"good". And all the "good" commits must be related to the bad commit. +They cannot be on a branch that has no link with the branch of the +"bad" commit. But it is possible for a good commit to be related to a +bad commit and yet not be neither one of its ancestor nor one of its +descendants. + +For example, there can be a "main" branch, and a "dev" branch that was +forked of the main branch at a commit named "D" like this: + +------------- +A-B-C-D-E-F-G <--main + \ + H-I-J <--dev +------------- + +The commit "D" is called a "merge base" for branch "main" and "dev" +because it's the best common ancestor for these branches for a merge. + +Now let's suppose that commit J is bad and commit G is good and that +we apply the bisection algorithm like it has been previously +described. + +As described in step 1) b) of the bisection algorithm, we remove all +the ancestors of the good commits because they are supposed to be good +too. + +So we would be left with only: + +------------- +H-I-J +------------- + +But what happens if the first bad commit is "B" and if it has been +fixed in the "main" branch by commit "F"? + +The result of such a bisection would be that we would find that H is +the first bad commit, when in fact it's B. So that would be wrong! + +And yes it's can happen in practice that people working on one branch +are not aware that people working on another branch fixed a bug! It +could also happen that F fixed more than one bug or that it is a +revert of some big development effort that was not ready to be +released. + +In fact development teams often maintain both a development branch and +a maintenance branch, and it would be quite easy for them if "git +bisect" just worked when they want to bisect a regression on the +development branch that is not on the maintenance branch. They should +be able to start bisecting using: + +------------- +$ git bisect start dev main +------------- + +To enable that additional nice feature, when a bisection is started +and when some good commits are not ancestors of the bad commit, we +first compute the merge bases between the bad and the good commits and +we chose these merge bases as the first commits that will be checked +out and tested. + +If it happens that one merge base is bad, then the bisection process +is stopped with a message like: + +------------- +The merge base BBBBBB is bad. +This means the bug has been fixed between BBBBBB and [GGGGGG,...]. +------------- + +where BBBBBB is the sha1 hash of the bad merge base and [GGGGGG,...] +is a comma separated list of the sha1 of the good commits. + +If some of the merge bases are skipped, then the bisection process +continues, but the following message is printed for each skipped merge +base: + +------------- +Warning: the merge base between BBBBBB and [GGGGGG,...] must be skipped. +So we cannot be sure the first bad commit is between MMMMMM and BBBBBB. +We continue anyway. +------------- + +where BBBBBB is the sha1 hash of the bad commit, MMMMMM is the sha1 +hash of the merge base that is skipped and [GGGGGG,...] is a comma +separated list of the sha1 of the good commits. + +So if there is no bad merge base, the bisection process continues as +usual after this step. + +Best bisecting practices +------------------------ + +Using test suites and git bisect together +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + +If you both have a test suite and use git bisect, then it becomes less +important to check that all tests pass after each commit. Though of +course it is probably a good idea to have some checks to avoid +breaking too many things because it could make bisecting other bugs +more difficult. + +You can focus your efforts to check at a few points (for example rc +and beta releases) that all the T test cases pass for all the N +configurations. And when some tests don't pass you can use "git +bisect" (or better "git bisect run"). So you should perform roughly: + +------------- +c * N * T + b * M * log2(M) tests +------------- + +where c is the number of rounds of test (so a small constant) and b is +the ratio of bug per commit (hopefully a small constant too). + +So of course it's much better as it's O(N \* T) vs O(N \* T \* M) if +you would test everything after each commit. + +This means that test suites are good to prevent some bugs from being +committed and they are also quite good to tell you that you have some +bugs. But they are not so good to tell you where some bugs have been +introduced. To tell you that efficiently, git bisect is needed. + +The other nice thing with test suites, is that when you have one, you +already know how to test for bad behavior. So you can use this +knowledge to create a new test case for "git bisect" when it appears +that there is a regression. So it will be easier to bisect the bug and +fix it. And then you can add the test case you just created to your +test suite. + +So if you know how to create test cases and how to bisect, you will be +subject to a virtuous circle: + +more tests => easier to create tests => easier to bisect => more tests + +So test suites and "git bisect" are complementary tools that are very +powerful and efficient when used together. + +Bisecting build failures +~~~~~~~~~~~~~~~~~~~~~~~~ + +You can very easily automatically bisect broken builds using something +like: + +------------- +$ git bisect start BAD GOOD +$ git bisect run make +------------- + +Passing sh -c "some commands" to "git bisect run" +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + +For example: + +------------- +$ git bisect run sh -c "make || exit 125; ./my_app | grep 'good output'" +------------- + +On the other hand if you do this often, then it can be worth having +scripts to avoid too much typing. + +Finding performance regressions +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + +Here is an example script that comes slightly modified from a real +world script used by Junio Hamano <<4>>. + +This script can be passed to "git bisect run" to find the commit that +introduced a performance regression: + +------------- +#!/bin/sh + +# Build errors are not what I am interested in. +make my_app || exit 255 + +# We are checking if it stops in a reasonable amount of time, so +# let it run in the background... + +./my_app >log 2>&1 & + +# ... and grab its process ID. +pid=$! + +# ... and then wait for sufficiently long. +sleep $NORMAL_TIME + +# ... and then see if the process is still there. +if kill -0 $pid +then + # It is still running -- that is bad. + kill $pid; sleep 1; kill $pid; + exit 1 +else + # It has already finished (the $pid process was no more), + # and we are happy. + exit 0 +fi +------------- + +Following general best practices +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + +It is obviously a good idea not to have commits with changes that +knowingly break things, even if some other commits later fix the +breakage. + +It is also a good idea when using any VCS to have only one small +logical change in each commit. + +The smaller the changes in your commit, the most effective "git +bisect" will be. And you will probably need "git bisect" less in the +first place, as small changes are easier to review even if they are +only reviewed by the commiter. + +Another good idea is to have good commit messages. They can be very +helpful to understand why some changes were made. + +These general best practices are very helpful if you bisect often. + +Avoiding bug prone merges +~~~~~~~~~~~~~~~~~~~~~~~~~ + +First merges by themselves can introduce some regressions even when +the merge needs no source code conflict resolution. This is because a +semantic change can happen in one branch while the other branch is not +aware of it. + +For example one branch can change the semantic of a function while the +other branch add more calls to the same function. + +This is made much worse if many files have to be fixed to resolve +conflicts. That's why such merges are called "evil merges". They can +make regressions very difficult to track down. It can even be +misleading to know the first bad commit if it happens to be such a +merge, because people might think that the bug comes from bad conflict +resolution when it comes from a semantic change in one branch. + +Anyway "git rebase" can be used to linearize history. This can be used +either to avoid merging in the first place. Or it can be used to +bisect on a linear history instead of the non linear one, as this +should give more information in case of a semantic change in one +branch. + +Merges can be also made simpler by using smaller branches or by using +many topic branches instead of only long version related branches. + +And testing can be done more often in special integration branches +like linux-next for the linux kernel. + +Adapting your work-flow +~~~~~~~~~~~~~~~~~~~~~~~ + +A special work-flow to process regressions can give great results. + +Here is an example of a work-flow used by Andreas Ericsson: + +* write, in the test suite, a test script that exposes the regression +* use "git bisect run" to find the commit that introduced it +* fix the bug that is often made obvious by the previous step +* commit both the fix and the test script (and if needed more tests) + +And here is what Andreas said about this work-flow <<5>>: + +_____________ +To give some hard figures, we used to have an average report-to-fix +cycle of 142.6 hours (according to our somewhat weird bug-tracker +which just measures wall-clock time). Since we moved to git, we've +lowered that to 16.2 hours. Primarily because we can stay on top of +the bug fixing now, and because everyone's jockeying to get to fix +bugs (we're quite proud of how lazy we are to let git find the bugs +for us). Each new release results in ~40% fewer bugs (almost certainly +due to how we now feel about writing tests). +_____________ + +Clearly this work-flow uses the virtuous circle between test suites +and "git bisect". In fact it makes it the standard procedure to deal +with regression. + +In other messages Andreas says that they also use the "best practices" +described above: small logical commits, topic branches, no evil +merge,... These practices all improve the bisectability of the commit +graph, by making it easier and more useful to bisect. + +So a good work-flow should be designed around the above points. That +is making bisecting easier, more useful and standard. + +Involving QA people and if possible end users +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + +One nice about "git bisect" is that it is not only a developer +tool. It can effectively be used by QA people or even end users (if +they have access to the source code or if they can get access to all +the builds). + +There was a discussion at one point on the linux kernel mailing list +of whether it was ok to always ask end user to bisect, and very good +points were made to support the point of view that it is ok. + +For example David Miller wrote <<6>>: + +_____________ +What people don't get is that this is a situation where the "end node +principle" applies. When you have limited resources (here: developers) +you don't push the bulk of the burden upon them. Instead you push +things out to the resource you have a lot of, the end nodes (here: +users), so that the situation actually scales. +_____________ + +This means that it is often "cheaper" if QA people or end users can do +it. + +What is interesting too is that end users that are reporting bugs (or +QA people that reproduced a bug) have access to the environment where +the bug happens. So they can often more easily reproduce a +regression. And if they can bisect, then more information will be +extracted from the environment where the bug happens, which means that +it will be easier to understand and then fix the bug. + +For open source projects it can be a good way to get more useful +contributions from end users, and to introduce them to QA and +development activities. + +Using complex scripts +~~~~~~~~~~~~~~~~~~~~~ + +In some cases like for kernel development it can be worth developing +complex scripts to be able to fully automate bisecting. + +Here is what Ingo Molnar says about that <<7>>: + +_____________ +i have a fully automated bootup-hang bisection script. It is based on +"git-bisect run". I run the script, it builds and boots kernels fully +automatically, and when the bootup fails (the script notices that via +the serial log, which it continuously watches - or via a timeout, if +the system does not come up within 10 minutes it's a "bad" kernel), +the script raises my attention via a beep and i power cycle the test +box. (yeah, i should make use of a managed power outlet to 100% +automate it) +_____________ + +Combining test suites, git bisect and other systems together +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + +We have seen that test suites an git bisect are very powerful when +used together. It can be even more powerful if you can combine them +with other systems. + +For example some test suites could be run automatically at night with +some unusual (or even random) configurations. And if a regression is +found by a test suite, then "git bisect" can be automatically +launched, and its result can be emailed to the author of the first bad +commit found by "git bisect", and perhaps other people too. And a new +entry in the bug tracking system could be automatically created too. + + +The future of bisecting +----------------------- + +"git replace" +~~~~~~~~~~~~~ + +We saw earlier that "git bisect skip" is now using a PRNG to try to +avoid areas in the commit graph where commits are untestable. The +problem is that sometimes the first bad commit will be in an +untestable area. + +To simplify the discussion we will suppose that the untestable area is +a simple string of commits and that it was created by a breakage +introduced by one commit (let's call it BBC for bisect breaking +commit) and later fixed by another one (let's call it BFC for bisect +fixing commit). + +For example: + +------------- +...-Y-BBC-X1-X2-X3-X4-X5-X6-BFC-Z-... +------------- + +where we know that Y is good and BFC is bad, and where BBC and X1 to +X6 are untestable. + +In this case if you are bisecting manually, what you can do is create +a special branch that starts just before the BBC. The first commit in +this branch should be the BBC with the BFC squashed into it. And the +other commits in the branch should be the commits between BBC and BFC +rebased on the first commit of the branch and then the commit after +BFC also rebased on. + +For example: + +------------- + (BBC+BFC)-X1'-X2'-X3'-X4'-X5'-X6'-Z' + / +...-Y-BBC-X1-X2-X3-X4-X5-X6-BFC-Z-... +------------- + +where commits quoted with ' have been rebased. + +You can easily create such a branch with Git using interactive rebase. + +For example using: + +------------- +$ git rebase -i Y Z +------------- + +and then moving BFC after BBC and squashing it. + +After that you can start bisecting as usual in the new branch and you +should eventually find the first bad commit. + +For example: + +------------- +$ git bisect start Z' Y +------------- + +If you are using "git bisect run", you can use the same manual fix up +as above, and then start another "git bisect run" in the special +branch. Or as the "git bisect" man page says, the script passed to +"git bisect run" can apply a patch before it compiles and test the +software <<8>>. The patch should turn a current untestable commits +into a testable one. So the testing will result in "good" or "bad" and +"git bisect" will be able to find the first bad commit. And the script +should not forget to remove the patch once the testing is done before +exiting from the script. + +(Note that instead of a patch you can use "git cherry-pick BFC" to +apply the fix, and in this case you should use "git reset --hard +HEAD^" to revert the cherry-pick after testing and before returning +from the script.) + +But the above ways to work around untestable areas are a little bit +clunky. Using special branches is nice because these branches can be +shared by developers like usual branches, but the risk is that people +will get many such branches. And it disrupts the normal "git bisect" +work-flow. So, if you want to use "git bisect run" completely +automatically, you have to add special code in your script to restart +bisection in the special branches. + +Anyway one can notice in the above special branch example that the Z' +and Z commits should point to the same source code state (the same +"tree" in git parlance). That's because Z' result from applying the +same changes as Z just in a slightly different order. + +So if we could just "replace" Z by Z' when we bisect, then we would +not need to add anything to a script. It would just work for anyone in +the project sharing the special branches and the replacements. + +With the example above that would give: + +------------- + (BBC+BFC)-X1'-X2'-X3'-X4'-X5'-X6'-Z'-... + / +...-Y-BBC-X1-X2-X3-X4-X5-X6-BFC-Z +------------- + +That's why the "git replace" command was created. Technically it +stores replacements "refs" in the "refs/replace/" hierarchy. These +"refs" are like branches (that are stored in "refs/heads/") or tags +(that are stored in "refs/tags"), and that means that they can +automatically be shared like branches or tags among developers. + +"git replace" is a very powerful mechanism. It can be used to fix +commits in already released history, for example to change the commit +message or the author. And it can also be used instead of git "grafts" +to link a repository with another old repository. + +In fact it's this last feature that "sold" it to the git community, so +it is now in the "master" branch of git's git repository and it should +be released in git 1.6.5 in October or November 2009. + +One problem with "git replace" is that currently it stores all the +replacements refs in "refs/replace/", but it would be perhaps better +if the replacement refs that are useful only for bisecting would be in +"refs/replace/bisect/". This way the replacement refs could be used +only for bisecting, while other refs directly in "refs/replace/" would +be used nearly all the time. + +Bisecting sporadic bugs +~~~~~~~~~~~~~~~~~~~~~~~ + +Another possible improvement to "git bisect" would be to optionally +add some redundancy to the tests performed so that it would be more +reliable when tracking sporadic bugs. + +This has been requested by some kernel developers because some bugs +called sporadic bugs do not appear in all the kernel builds because +they are very dependent on the compiler output. + +The idea is that every 3 test for example, "git bisect" could ask the +user to test a commit that has already been found to be "good" or +"bad" (because one of its descendants or one of its ancestors has been +found to be "good" or "bad" respectively). If it happens that a commit +has been previously incorrectly classified then the bisection can be +aborted early, hopefully before too many mistakes have been made. Then +the user will have to look at what happened and then restart the +bisection using a fixed bisect log. + +There is already a project called BBChop created by Ealdwulf Wuffinga +on Github that does something like that using Bayesian Search Theory +<<9>>: + +_____________ +BBChop is like 'git bisect' (or equivalent), but works when your bug +is intermittent. That is, it works in the presence of false negatives +(when a version happens to work this time even though it contains the +bug). It assumes that there are no false positives (in principle, the +same approach would work, but adding it may be non-trivial). +_____________ + +But BBChop is independent of any VCS and it would be easier for Git +users to have something integrated in Git. + +Conclusion +---------- + +We have seen that regressions are an important problem, and that "git +bisect" has nice features that complement very well practices and +other tools, especially test suites, that are generally used to fight +regressions. But it might be needed to change some work-flows and +(bad) habits to get the most out of it. + +Some improvements to the algorithms inside "git bisect" are possible +and some new features could help in some cases, but overall "git +bisect" works already very well, is used a lot, and is already very +useful. To back up that last claim, let's give the final word to Ingo +Molnar when he was asked by the author how much time does he think +"git bisect" saves him when he uses it: + +_____________ +a _lot_. + +About ten years ago did i do my first 'bisection' of a Linux patch +queue. That was prior the Git (and even prior the BitKeeper) days. I +literally days spent sorting out patches, creating what in essence +were standalone commits that i guessed to be related to that bug. + +It was a tool of absolute last resort. I'd rather spend days looking +at printk output than do a manual 'patch bisection'. + +With Git bisect it's a breeze: in the best case i can get a ~15 step +kernel bisection done in 20-30 minutes, in an automated way. Even with +manual help or when bisecting multiple, overlapping bugs, it's rarely +more than an hour. + +In fact it's invaluable because there are bugs i would never even +_try_ to debug if it wasn't for git bisect. In the past there were bug +patterns that were immediately hopeless for me to debug - at best i +could send the crash/bug signature to lkml and hope that someone else +can think of something. + +And even if a bisection fails today it tells us something valuable +about the bug: that it's non-deterministic - timing or kernel image +layout dependent. + +So git bisect is unconditional goodness - and feel free to quote that +;-) +_____________ + +Acknowledgements +---------------- + +Many thanks to Junio Hamano for his help in reviewing this paper, for +reviewing the patches I sent to the git mailing list, for discussing +some ideas and helping me improve them, for improving "git bisect" a +lot and for his awesome work in maintaining and developing Git. + +Many thanks to Ingo Molnar for giving me very useful information that +appears in this paper, for commenting on this paper, for his +suggestions to improve "git bisect" and for evangelizing "git bisect" +on the linux kernel mailing lists. + +Many thanks to Linus Torvalds for inventing, developing and +evangelizing "git bisect", Git and Linux. + +Many thanks to the many other great people who helped one way or +another when I worked on git, especially to Andreas Ericsson, Johannes +Schindelin, H. Peter Anvin, Daniel Barkalow, Bill Lear, John Hawley, +Shawn O. Pierce, Jeff King, Sam Vilain, Jon Seymour. + +Many thanks to the Linux-Kongress program committee for choosing the +author to given a talk and for publishing this paper. + +References +---------- + +- [[[1]]] http://www.nist.gov/public_affairs/releases/n02-10.htm['Software Errors Cost U.S. Economy $59.5 Billion Annually'. Nist News Release.] +- [[[2]]] http://java.sun.com/docs/codeconv/html/CodeConventions.doc.html#16712['Code Conventions for the Java Programming Language'. Sun Microsystems.] +- [[[3]]] http://en.wikipedia.org/wiki/Software_maintenance['Software maintenance'. Wikipedia.] +- [[[4]]] http://article.gmane.org/gmane.comp.version-control.git/45195/[Junio C Hamano. 'Automated bisect success story'. Gmane.] +- [[[5]]] http://lwn.net/Articles/317154/[Christian Couder. 'Fully automated bisecting with "git bisect run"'. LWN.net.] +- [[[6]]] http://lwn.net/Articles/277872/[Jonathan Corbet. 'Bisection divides users and developers'. LWN.net.] +- [[[7]]] http://article.gmane.org/gmane.linux.scsi/36652/[Ingo Molnar. 'Re: BUG 2.6.23-rc3 can't see sd partitions on Alpha'. Gmane.] +- [[[8]]] http://www.kernel.org/pub/software/scm/git/docs/git-bisect.html[Junio C Hamano and the git-list. 'git-bisect(1) Manual Page'. Linux Kernel Archives.] +- [[[9]]] http://github.com/Ealdwulf/bbchop[Ealdwulf. 'bbchop'. GitHub.] diff --git a/Documentation/git-bisect.txt b/Documentation/git-bisect.txt index 63e7a42cb3..c39d957c3a 100644 --- a/Documentation/git-bisect.txt +++ b/Documentation/git-bisect.txt @@ -20,7 +20,7 @@ on the subcommand: git bisect bad [<rev>] git bisect good [<rev>...] git bisect skip [(<rev>|<range>)...] - git bisect reset [<branch>] + git bisect reset [<commit>] git bisect visualize git bisect replay <logfile> git bisect log @@ -81,16 +81,27 @@ will have been left with the first bad kernel revision in "refs/bisect/bad". Bisect reset ~~~~~~~~~~~~ -To return to the original head after a bisect session, issue the -following command: +After a bisect session, to clean up the bisection state and return to +the original HEAD, issue the following command: ------------------------------------------------ $ git bisect reset ------------------------------------------------ -This resets the tree to the original branch instead of being on the -bisection commit ("git bisect start" will also do that, as it resets -the bisection state). +By default, this will return your tree to the commit that was checked +out before `git bisect start`. (A new `git bisect start` will also do +that, as it cleans up the old bisection state.) + +With an optional argument, you can return to a different commit +instead: + +------------------------------------------------ +$ git bisect reset <commit> +------------------------------------------------ + +For example, `git bisect reset HEAD` will leave you on the current +bisection commit and avoid switching commits at all, while `git bisect +reset bisect/bad` will check out the first bad revision. Bisect visualize ~~~~~~~~~~~~~~~~ @@ -319,6 +330,11 @@ Documentation ------------- Documentation by Junio C Hamano and the git-list <git@vger.kernel.org>. +SEE ALSO +-------- +link:git-bisect-lk2009.html[Fighting regressions with git bisect], +linkgit:git-blame[1]. + GIT --- Part of the linkgit:git[1] suite diff --git a/Documentation/git-check-ref-format.txt b/Documentation/git-check-ref-format.txt index e9b3b40af4..0aeef24780 100644 --- a/Documentation/git-check-ref-format.txt +++ b/Documentation/git-check-ref-format.txt @@ -9,6 +9,7 @@ SYNOPSIS -------- [verse] 'git check-ref-format' <refname> +'git check-ref-format' --print <refname> 'git check-ref-format' --branch <branchname-shorthand> DESCRIPTION @@ -63,19 +64,31 @@ reference name expressions (see linkgit:git-rev-parse[1]): . at-open-brace `@{` is used as a notation to access a reflog entry. +With the `--print` option, if 'refname' is acceptable, it prints the +canonicalized name of a hypothetical reference with that name. That is, +it prints 'refname' with any extra `/` characters removed. + With the `--branch` option, it expands the ``previous branch syntax'' `@{-n}`. For example, `@{-1}` is a way to refer the last branch you were on. This option should be used by porcelains to accept this syntax anywhere a branch name is expected, so they can act as if you typed the branch name. -EXAMPLE -------- - -git check-ref-format --branch @{-1}:: - -Print the name of the previous branch. +EXAMPLES +-------- +* Print the name of the previous branch: ++ +------------ +$ git check-ref-format --branch @{-1} +------------ + +* Determine the reference name to use for a new branch: ++ +------------ +$ ref=$(git check-ref-format --print "refs/heads/$newbranch") || +die "we do not like '$newbranch' as a branch name." +------------ GIT --- diff --git a/Documentation/git-commit.txt b/Documentation/git-commit.txt index 0578a40d84..d227cec9ba 100644 --- a/Documentation/git-commit.txt +++ b/Documentation/git-commit.txt @@ -9,7 +9,7 @@ SYNOPSIS -------- [verse] 'git commit' [-a | --interactive] [-s] [-v] [-u<mode>] [--amend] [--dry-run] - [(-c | -C) <commit>] [-F <file> | -m <msg>] + [(-c | -C) <commit>] [-F <file> | -m <msg>] [--reset-author] [--allow-empty] [--no-verify] [-e] [--author=<author>] [--cleanup=<mode>] [--] [[-i | -o ]<file>...] @@ -69,6 +69,11 @@ OPTIONS Like '-C', but with '-c' the editor is invoked, so that the user can further edit the commit message. +--reset-author:: + When used with -C/-c/--amend options, declare that the + authorship of the resulting commit now belongs of the committer. + This also renews the author timestamp. + -F <file>:: --file=<file>:: Take the commit message from the given file. Use '-' to @@ -323,7 +328,7 @@ ENVIRONMENT AND CONFIGURATION VARIABLES The editor used to edit the commit log message will be chosen from the GIT_EDITOR environment variable, the core.editor configuration variable, the VISUAL environment variable, or the EDITOR environment variable (in that -order). +order). See linkgit:git-var[1] for details. HOOKS ----- diff --git a/Documentation/git-cvsserver.txt b/Documentation/git-cvsserver.txt index 785779e221..99a7c14700 100644 --- a/Documentation/git-cvsserver.txt +++ b/Documentation/git-cvsserver.txt @@ -182,10 +182,9 @@ Database Backend ---------------- 'git-cvsserver' uses one database per git head (i.e. CVS module) to -store information about the repository for faster access. The -database doesn't contain any persistent data and can be completely -regenerated from the git repository at any time. The database -needs to be updated (i.e. written to) after every commit. +store information about the repository to maintain consistent +CVS revision numbers. The database needs to be +updated (i.e. written to) after every commit. If the commit is done directly by using `git` (as opposed to using 'git-cvsserver') the update will need to happen on the @@ -204,6 +203,18 @@ write so it might not be enough to grant the users using 'git-cvsserver' write access to the database file without granting them write access to the directory, too. +The database can not be reliably regenerated in a +consistent form after the branch it is tracking has changed. +Example: For merged branches, 'git-cvsserver' only tracks +one branch of development, and after a 'git-merge' an +incrementally updated database may track a different branch +than a database regenerated from scratch, causing inconsistent +CVS revision numbers. `git-cvsserver` has no way of knowing which +branch it would have picked if it had been run incrementally +pre-merge. So if you have to fully or partially (from old +backup) regenerate the database, you should be suspicious +of pre-existing CVS sandboxes. + You can configure the database backend with the following configuration variables: diff --git a/Documentation/git-describe.txt b/Documentation/git-describe.txt index 2f97916781..78b9808aa3 100644 --- a/Documentation/git-describe.txt +++ b/Documentation/git-describe.txt @@ -8,7 +8,9 @@ git-describe - Show the most recent tag that is reachable from a commit SYNOPSIS -------- +[verse] 'git describe' [--all] [--tags] [--contains] [--abbrev=<n>] <committish>... +'git describe' [--all] [--tags] [--contains] [--abbrev=<n>] --dirty[=<mark>] DESCRIPTION ----------- @@ -27,6 +29,11 @@ OPTIONS <committish>...:: Committish object names to describe. +--dirty[=<mark>]:: + Describe the working tree. + It means describe HEAD and appends <mark> (`-dirty` by + default) if the working tree is dirty. + --all:: Instead of using only the annotated tags, use any ref found in `.git/refs/`. This option enables matching diff --git a/Documentation/git-difftool.txt b/Documentation/git-difftool.txt index 96a6c51a4b..8e9aed67d7 100644 --- a/Documentation/git-difftool.txt +++ b/Documentation/git-difftool.txt @@ -31,7 +31,7 @@ OPTIONS Use the diff tool specified by <tool>. Valid merge tools are: kdiff3, kompare, tkdiff, meld, xxdiff, emerge, vimdiff, gvimdiff, - ecmerge, diffuse, opendiff and araxis. + ecmerge, diffuse, opendiff, p4merge and araxis. + If a diff tool is not specified, 'git-difftool' will use the configuration variable `diff.tool`. If the diff --git a/Documentation/git-fast-import.txt b/Documentation/git-fast-import.txt index c2f483a8d2..288032c7b8 100644 --- a/Documentation/git-fast-import.txt +++ b/Documentation/git-fast-import.txt @@ -316,7 +316,7 @@ change to the project. data ('from' SP <committish> LF)? ('merge' SP <committish> LF)? - (filemodify | filedelete | filecopy | filerename | filedeleteall)* + (filemodify | filedelete | filecopy | filerename | filedeleteall | notemodify)* LF? .... @@ -339,14 +339,13 @@ commit message use a 0 length data. Commit messages are free-form and are not interpreted by Git. Currently they must be encoded in UTF-8, as fast-import does not permit other encodings to be specified. -Zero or more `filemodify`, `filedelete`, `filecopy`, `filerename` -and `filedeleteall` commands +Zero or more `filemodify`, `filedelete`, `filecopy`, `filerename`, +`filedeleteall` and `notemodify` commands may be included to update the contents of the branch prior to creating the commit. These commands may be supplied in any order. However it is recommended that a `filedeleteall` command precede -all `filemodify`, `filecopy` and `filerename` commands in the same -commit, as `filedeleteall` -wipes the branch clean (see below). +all `filemodify`, `filecopy`, `filerename` and `notemodify` commands in +the same commit, as `filedeleteall` wipes the branch clean (see below). The `LF` after the command is optional (it used to be required). @@ -595,6 +594,40 @@ more memory per active branch (less than 1 MiB for even most large projects); so frontends that can easily obtain only the affected paths for a commit are encouraged to do so. +`notemodify` +^^^^^^^^^^^^ +Included in a `commit` command to add a new note (annotating a given +commit) or change the content of an existing note. This command has +two different means of specifying the content of the note. + +External data format:: + The data content for the note was already supplied by a prior + `blob` command. The frontend just needs to connect it to the + commit that is to be annotated. ++ +.... + 'N' SP <dataref> SP <committish> LF +.... ++ +Here `<dataref>` can be either a mark reference (`:<idnum>`) +set by a prior `blob` command, or a full 40-byte SHA-1 of an +existing Git blob object. + +Inline data format:: + The data content for the note has not been supplied yet. + The frontend wants to supply it as part of this modify + command. ++ +.... + 'N' SP 'inline' SP <committish> LF + data +.... ++ +See below for a detailed description of the `data` command. + +In both formats `<committish>` is any of the commit specification +expressions also accepted by `from` (see above). + `mark` ~~~~~~ Arranges for fast-import to save a reference to the current object, allowing diff --git a/Documentation/git-fetch.txt b/Documentation/git-fetch.txt index f2483d624e..9b9e5686e4 100644 --- a/Documentation/git-fetch.txt +++ b/Documentation/git-fetch.txt @@ -10,11 +10,17 @@ SYNOPSIS -------- 'git fetch' <options> <repository> <refspec>... +'git fetch' <options> <group> + +'git fetch' --multiple <options> [<repository> | <group>]... + +'git fetch' --all <options> + DESCRIPTION ----------- -Fetches named heads or tags from another repository, along with -the objects necessary to complete them. +Fetches named heads or tags from one or more other repositories, +along with the objects necessary to complete them. The ref names and their object names of fetched refs are stored in `.git/FETCH_HEAD`. This information is left for a later merge @@ -28,6 +34,10 @@ pointed by remote tags that it does not yet have, then fetch those missing tags. If the other end has tags that point at branches you are not interested in, you will not get them. +'git fetch' can fetch from either a single named repository, or +or from several repositories at once if <group> is given and +there is a remotes.<group> entry in the configuration file. +(See linkgit:git-config[1]). OPTIONS ------- diff --git a/Documentation/git-filter-branch.txt b/Documentation/git-filter-branch.txt index 2b40babb6b..394a77a35f 100644 --- a/Documentation/git-filter-branch.txt +++ b/Documentation/git-filter-branch.txt @@ -159,7 +159,18 @@ to other tags will be rewritten to point to the underlying commit. --subdirectory-filter <directory>:: Only look at the history which touches the given subdirectory. The result will contain that directory (and only that) as its - project root. + project root. Implies --remap-to-ancestor. + +--remap-to-ancestor:: + Rewrite refs to the nearest rewritten ancestor instead of + ignoring them. ++ +Normally, positive refs on the command line are only changed if the +commit they point to was rewritten. However, you can limit the extent +of this rewriting by using linkgit:rev-list[1] arguments, e.g., path +limiters. Refs pointing to such excluded commits would then normally +be ignored. With this option, they are instead rewritten to point at +the nearest ancestor that was not excluded. --prune-empty:: Some kind of filters will generate empty commits, that left the tree diff --git a/Documentation/git-format-patch.txt b/Documentation/git-format-patch.txt index 687e667598..f1fd0df08a 100644 --- a/Documentation/git-format-patch.txt +++ b/Documentation/git-format-patch.txt @@ -43,28 +43,28 @@ There are two ways to specify which commits to operate on. The first rule takes precedence in the case of a single <commit>. To apply the second rule, i.e., format everything since the beginning of -history up until <commit>, use the '\--root' option: "git format-patch -\--root <commit>". If you want to format only <commit> itself, you -can do this with "git format-patch -1 <commit>". +history up until <commit>, use the '\--root' option: `git format-patch +\--root <commit>`. If you want to format only <commit> itself, you +can do this with `git format-patch -1 <commit>`. By default, each output file is numbered sequentially from 1, and uses the first line of the commit message (massaged for pathname safety) as -the filename. With the --numbered-files option, the output file names +the filename. With the `--numbered-files` option, the output file names will only be numbers, without the first line of the commit appended. The names of the output files are printed to standard -output, unless the --stdout option is specified. +output, unless the `--stdout` option is specified. -If -o is specified, output files are created in <dir>. Otherwise +If `-o` is specified, output files are created in <dir>. Otherwise they are created in the current working directory. By default, the subject of a single patch is "[PATCH] First Line" and the subject when multiple patches are output is "[PATCH n/m] First -Line". To force 1/1 to be added for a single patch, use -n. To omit -patch numbers from the subject, use -N +Line". To force 1/1 to be added for a single patch, use `-n`. To omit +patch numbers from the subject, use `-N`. -If given --thread, 'git-format-patch' will generate In-Reply-To and -References headers to make the second and subsequent patch mails appear -as replies to the first mail; this also generates a Message-Id header to +If given `--thread`, `git-format-patch` will generate `In-Reply-To` and +`References` headers to make the second and subsequent patch mails appear +as replies to the first mail; this also generates a `Message-Id` header to reference. OPTIONS @@ -112,7 +112,7 @@ include::diff-options.txt[] --attach[=<boundary>]:: Create multipart/mixed attachment, the first part of which is the commit message and the patch itself in the - second part, with "Content-Disposition: attachment". + second part, with `Content-Disposition: attachment`. --no-attach:: Disable the creation of an attachment, overriding the @@ -121,13 +121,13 @@ include::diff-options.txt[] --inline[=<boundary>]:: Create multipart/mixed attachment, the first part of which is the commit message and the patch itself in the - second part, with "Content-Disposition: inline". + second part, with `Content-Disposition: inline`. --thread[=<style>]:: --no-thread:: - Controls addition of In-Reply-To and References headers to + Controls addition of `In-Reply-To` and `References` headers to make the second and subsequent mails appear as replies to the - first. Also controls generation of the Message-Id header to + first. Also controls generation of the `Message-Id` header to reference. + The optional <style> argument can be either `shallow` or `deep`. @@ -136,16 +136,16 @@ series, where the head is chosen from the cover letter, the `\--in-reply-to`, and the first patch mail, in this order. 'deep' threading makes every mail a reply to the previous one. + -The default is --no-thread, unless the 'format.thread' configuration -is set. If --thread is specified without a style, it defaults to the +The default is `--no-thread`, unless the 'format.thread' configuration +is set. If `--thread` is specified without a style, it defaults to the style specified by 'format.thread' if any, or else `shallow`. + Beware that the default for 'git send-email' is to thread emails -itself. If you want 'git format-patch' to take care of hreading, you -will want to ensure that threading is disabled for 'git send-email'. +itself. If you want `git format-patch` to take care of threading, you +will want to ensure that threading is disabled for `git send-email`. --in-reply-to=Message-Id:: - Make the first mail (or all the mails with --no-thread) appear as a + Make the first mail (or all the mails with `--no-thread`) appear as a reply to the given Message-Id, which avoids breaking threads to provide a new patch series. @@ -160,16 +160,16 @@ will want to ensure that threading is disabled for 'git send-email'. Instead of the standard '[PATCH]' prefix in the subject line, instead use '[<Subject-Prefix>]'. This allows for useful naming of a patch series, and can be - combined with the --numbered option. + combined with the `--numbered` option. --cc=<email>:: - Add a "Cc:" header to the email headers. This is in addition + Add a `Cc:` header to the email headers. This is in addition to any configured headers, and may be used multiple times. --add-header=<header>:: Add an arbitrary header to the email headers. This is in addition to any configured headers, and may be used multiple times. - For example, --add-header="Organization: git-foo" + For example, `--add-header="Organization: git-foo"` --cover-letter:: In addition to the patches, generate a cover letter file diff --git a/Documentation/git-fsck.txt b/Documentation/git-fsck.txt index 287c4fc5e0..6fe9484da3 100644 --- a/Documentation/git-fsck.txt +++ b/Documentation/git-fsck.txt @@ -10,7 +10,7 @@ SYNOPSIS -------- [verse] 'git fsck' [--tags] [--root] [--unreachable] [--cache] [--no-reflogs] - [--full] [--strict] [--verbose] [--lost-found] [<object>*] + [--[no-]full] [--strict] [--verbose] [--lost-found] [<object>*] DESCRIPTION ----------- @@ -52,7 +52,8 @@ index file, all SHA1 references in .git/refs/*, and all reflogs (unless or $GIT_DIR/objects/info/alternates, and in packed git archives found in $GIT_DIR/objects/pack and corresponding pack subdirectories in alternate - object pools. + object pools. This is now default; you can turn it off + with --no-full. --strict:: Enable more strict checking, namely to catch a file mode diff --git a/Documentation/git-http-backend.txt b/Documentation/git-http-backend.txt new file mode 100644 index 0000000000..67aec067c8 --- /dev/null +++ b/Documentation/git-http-backend.txt @@ -0,0 +1,178 @@ +git-http-backend(1) +=================== + +NAME +---- +git-http-backend - Server side implementation of Git over HTTP + +SYNOPSIS +-------- +[verse] +'git-http-backend' + +DESCRIPTION +----------- +A simple CGI program to serve the contents of a Git repository to Git +clients accessing the repository over http:// and https:// protocols. +The program supports clients fetching using both the smart HTTP protcol +and the backwards-compatible dumb HTTP protocol, as well as clients +pushing using the smart HTTP protocol. + +By default, only the `upload-pack` service is enabled, which serves +'git-fetch-pack' and 'git-ls-remote' clients, which are invoked from +'git-fetch', 'git-pull', and 'git-clone'. If the client is authenticated, +the `receive-pack` service is enabled, which serves 'git-send-pack' +clients, which is invoked from 'git-push'. + +SERVICES +-------- +These services can be enabled/disabled using the per-repository +configuration file: + +http.getanyfile:: + This serves older Git clients which are unable to use the + upload pack service. When enabled, clients are able to read + any file within the repository, including objects that are + no longer reachable from a branch but are still present. + It is enabled by default, but a repository can disable it + by setting this configuration item to `false`. + +http.uploadpack:: + This serves 'git-fetch-pack' and 'git-ls-remote' clients. + It is enabled by default, but a repository can disable it + by setting this configuration item to `false`. + +http.receivepack:: + This serves 'git-send-pack' clients, allowing push. It is + disabled by default for anonymous users, and enabled by + default for users authenticated by the web server. It can be + disabled by setting this item to `false`, or enabled for all + users, including anonymous users, by setting it to `true`. + +URL TRANSLATION +--------------- +To determine the location of the repository on disk, 'git-http-backend' +concatenates the environment variables PATH_INFO, which is set +automatically by the web server, and GIT_PROJECT_ROOT, which must be set +manually in the web server configuration. If GIT_PROJECT_ROOT is not +set, 'git-http-backend' reads PATH_TRANSLATED, which is also set +automatically by the web server. + +EXAMPLES +-------- +All of the following examples map 'http://$hostname/git/foo/bar.git' +to '/var/www/git/foo/bar.git'. + +Apache 2.x:: + Ensure mod_cgi, mod_alias, and mod_env are enabled, set + GIT_PROJECT_ROOT (or DocumentRoot) appropriately, and + create a ScriptAlias to the CGI: ++ +---------------------------------------------------------------- +SetEnv GIT_PROJECT_ROOT /var/www/git +ScriptAlias /git/ /usr/libexec/git-core/git-http-backend/ +---------------------------------------------------------------- ++ +To enable anonymous read access but authenticated write access, +require authorization with a LocationMatch directive: ++ +---------------------------------------------------------------- +<LocationMatch "^/git/.*/git-receive-pack$"> + AuthType Basic + AuthName "Git Access" + Require group committers + ... +</LocationMatch> +---------------------------------------------------------------- ++ +To require authentication for both reads and writes, use a Location +directive around the repository, or one of its parent directories: ++ +---------------------------------------------------------------- +<Location /git/private> + AuthType Basic + AuthName "Private Git Access" + Require group committers + ... +</Location> +---------------------------------------------------------------- ++ +To serve gitweb at the same url, use a ScriptAliasMatch to only +those URLs that 'git-http-backend' can handle, and forward the +rest to gitweb: ++ +---------------------------------------------------------------- +ScriptAliasMatch \ + "(?x)^/git/(.*/(HEAD | \ + info/refs | \ + objects/(info/[^/]+ | \ + [0-9a-f]{2}/[0-9a-f]{38} | \ + pack/pack-[0-9a-f]{40}\.(pack|idx)) | \ + git-(upload|receive)-pack))$" \ + /usr/libexec/git-core/git-http-backend/$1 + +ScriptAlias /git/ /var/www/cgi-bin/gitweb.cgi/ +---------------------------------------------------------------- + +Accelerated static Apache 2.x:: + Similar to the above, but Apache can be used to return static + files that are stored on disk. On many systems this may + be more efficient as Apache can ask the kernel to copy the + file contents from the file system directly to the network: ++ +---------------------------------------------------------------- +SetEnv GIT_PROJECT_ROOT /var/www/git + +AliasMatch ^/git/(.*/objects/[0-9a-f]{2}/[0-9a-f]{38})$ /var/www/git/$1 +AliasMatch ^/git/(.*/objects/pack/pack-[0-9a-f]{40}.(pack|idx))$ /var/www/git/$1 +ScriptAlias /git/ /usr/libexec/git-core/git-http-backend/ +---------------------------------------------------------------- ++ +This can be combined with the gitweb configuration: ++ +---------------------------------------------------------------- +SetEnv GIT_PROJECT_ROOT /var/www/git + +AliasMatch ^/git/(.*/objects/[0-9a-f]{2}/[0-9a-f]{38})$ /var/www/git/$1 +AliasMatch ^/git/(.*/objects/pack/pack-[0-9a-f]{40}.(pack|idx))$ /var/www/git/$1 +ScriptAliasMatch \ + "(?x)^/git/(.*/(HEAD | \ + info/refs | \ + objects/info/[^/]+ | \ + git-(upload|receive)-pack))$" \ + /usr/libexec/git-core/git-http-backend/$1 +ScriptAlias /git/ /var/www/cgi-bin/gitweb.cgi/ +---------------------------------------------------------------- + + +ENVIRONMENT +----------- +'git-http-backend' relies upon the CGI environment variables set +by the invoking web server, including: + +* PATH_INFO (if GIT_PROJECT_ROOT is set, otherwise PATH_TRANSLATED) +* REMOTE_USER +* REMOTE_ADDR +* CONTENT_TYPE +* QUERY_STRING +* REQUEST_METHOD + +The backend process sets GIT_COMMITTER_NAME to '$REMOTE_USER' and +GIT_COMMITTER_EMAIL to '$\{REMOTE_USER}@http.$\{REMOTE_ADDR\}', +ensuring that any reflogs created by 'git-receive-pack' contain some +identifying information of the remote user who performed the push. + +All CGI environment variables are available to each of the hooks +invoked by the 'git-receive-pack'. + +Author +------ +Written by Shawn O. Pearce <spearce@spearce.org>. + +Documentation +-------------- +Documentation by Shawn O. Pearce <spearce@spearce.org>. + +GIT +--- +Part of the linkgit:git[1] suite diff --git a/Documentation/git-http-push.txt b/Documentation/git-http-push.txt index aef383e0b1..ddf7a18dc4 100644 --- a/Documentation/git-http-push.txt +++ b/Documentation/git-http-push.txt @@ -82,11 +82,11 @@ destination side. Without '--force', the <src> ref is stored at the remote only if <dst> does not exist, or <dst> is a proper subset (i.e. an -ancestor) of <src>. This check, known as "fast forward check", +ancestor) of <src>. This check, known as "fast-forward check", is performed in order to avoid accidentally overwriting the remote ref and lose other peoples' commits from there. -With '--force', the fast forward check is disabled for all refs. +With '--force', the fast-forward check is disabled for all refs. Optionally, a <ref> parameter can be prefixed with a plus '+' sign to disable the fast-forward check only on that ref. diff --git a/Documentation/git-mailinfo.txt b/Documentation/git-mailinfo.txt index 996c3fcc6c..b81ac98cf0 100644 --- a/Documentation/git-mailinfo.txt +++ b/Documentation/git-mailinfo.txt @@ -8,7 +8,7 @@ git-mailinfo - Extracts patch and authorship from a single e-mail message SYNOPSIS -------- -'git mailinfo' [-k] [-u | --encoding=<encoding> | -n] [--scissors] <msg> <patch> +'git mailinfo' [-k|-b] [-u | --encoding=<encoding> | -n] [--scissors] <msg> <patch> DESCRIPTION @@ -32,6 +32,11 @@ OPTIONS munging, and is most useful when used to read back 'git-format-patch -k' output. +-b:: + When -k is not in effect, all leading strings bracketed with '[' + and ']' pairs are stripped. This option limits the stripping to + only the pairs whose bracketed string contains the word "PATCH". + -u:: The commit log message, author name and author email are taken from the e-mail, and after minimally decoding MIME diff --git a/Documentation/git-mergetool.txt b/Documentation/git-mergetool.txt index 68ed6c0956..4a6f7f3a2d 100644 --- a/Documentation/git-mergetool.txt +++ b/Documentation/git-mergetool.txt @@ -27,7 +27,7 @@ OPTIONS Use the merge resolution program specified by <tool>. Valid merge tools are: kdiff3, tkdiff, meld, xxdiff, emerge, vimdiff, gvimdiff, ecmerge, - diffuse, tortoisemerge, opendiff and araxis. + diffuse, tortoisemerge, opendiff, p4merge and araxis. + If a merge resolution program is not specified, 'git-mergetool' will use the configuration variable `merge.tool`. If the diff --git a/Documentation/git-notes.txt b/Documentation/git-notes.txt new file mode 100644 index 0000000000..94cceb1319 --- /dev/null +++ b/Documentation/git-notes.txt @@ -0,0 +1,60 @@ +git-notes(1) +============ + +NAME +---- +git-notes - Add/inspect commit notes + +SYNOPSIS +-------- +[verse] +'git-notes' (edit [-F <file> | -m <msg>] | show) [commit] + +DESCRIPTION +----------- +This command allows you to add notes to commit messages, without +changing the commit. To discern these notes from the message stored +in the commit object, the notes are indented like the message, after +an unindented line saying "Notes:". + +To disable commit notes, you have to set the config variable +core.notesRef to the empty string. Alternatively, you can set it +to a different ref, something like "refs/notes/bugzilla". This setting +can be overridden by the environment variable "GIT_NOTES_REF". + + +SUBCOMMANDS +----------- + +edit:: + Edit the notes for a given commit (defaults to HEAD). + +show:: + Show the notes for a given commit (defaults to HEAD). + + +OPTIONS +------- +-m <msg>:: + Use the given note message (instead of prompting). + If multiple `-m` (or `-F`) options are given, their + values are concatenated as separate paragraphs. + +-F <file>:: + Take the note message from the given file. Use '-' to + read the note message from the standard input. + If multiple `-F` (or `-m`) options are given, their + values are concatenated as separate paragraphs. + + +Author +------ +Written by Johannes Schindelin <johannes.schindelin@gmx.de> + +Documentation +------------- +Documentation by Johannes Schindelin + +GIT +--- +Part of the linkgit:git[7] suite diff --git a/Documentation/git-push.txt b/Documentation/git-push.txt index 37c88953d1..52c0538df5 100644 --- a/Documentation/git-push.txt +++ b/Documentation/git-push.txt @@ -50,9 +50,9 @@ updated. + The object referenced by <src> is used to update the <dst> reference on the remote side, but by default this is only allowed if the -update can fast forward <dst>. By having the optional leading `{plus}`, +update can fast-forward <dst>. By having the optional leading `{plus}`, you can tell git to update the <dst> ref even when the update is not a -fast forward. This does *not* attempt to merge <src> into <dst>. See +fast-forward. This does *not* attempt to merge <src> into <dst>. See EXAMPLES below for details. + `tag <tag>` means the same as `refs/tags/<tag>:refs/tags/<tag>`. @@ -60,7 +60,7 @@ EXAMPLES below for details. Pushing an empty <src> allows you to delete the <dst> ref from the remote repository. + -The special refspec `:` (or `{plus}:` to allow non-fast forward updates) +The special refspec `:` (or `{plus}:` to allow non-fast-forward updates) directs git to push "matching" branches: for every branch that exists on the local side, the remote side is updated if a branch of the same name already exists on the remote side. This is the default operation mode @@ -176,10 +176,10 @@ summary:: For a successfully pushed ref, the summary shows the old and new values of the ref in a form suitable for using as an argument to `git log` (this is `<old>..<new>` in most cases, and - `<old>...<new>` for forced non-fast forward updates). For a + `<old>...<new>` for forced non-fast-forward updates). For a failed update, more details are given for the failure. The string `rejected` indicates that git did not try to send the - ref at all (typically because it is not a fast forward). The + ref at all (typically because it is not a fast-forward). The string `remote rejected` indicates that the remote end refused the update; this rejection is typically caused by a hook on the remote side. The string `remote failure` indicates that the @@ -347,9 +347,9 @@ git push origin :experimental:: git push origin {plus}dev:master:: Update the origin repository's master branch with the dev branch, - allowing non-fast forward updates. *This can leave unreferenced + allowing non-fast-forward updates. *This can leave unreferenced commits dangling in the origin repository.* Consider the - following situation, where a fast forward is not possible: + following situation, where a fast-forward is not possible: + ---- o---o---o---A---B origin/master diff --git a/Documentation/git-read-tree.txt b/Documentation/git-read-tree.txt index 4a932b08c6..a10ce4ba40 100644 --- a/Documentation/git-read-tree.txt +++ b/Documentation/git-read-tree.txt @@ -144,7 +144,7 @@ Two Tree Merge Typically, this is invoked as `git read-tree -m $H $M`, where $H is the head commit of the current repository, and $M is the head of a foreign tree, which is simply ahead of $H (i.e. we are in a -fast forward situation). +fast-forward situation). When two trees are specified, the user is telling 'git-read-tree' the following: diff --git a/Documentation/git-rebase.txt b/Documentation/git-rebase.txt index 0aefc34d0d..ca5e1e8653 100644 --- a/Documentation/git-rebase.txt +++ b/Documentation/git-rebase.txt @@ -228,13 +228,23 @@ OPTIONS Use merging strategies to rebase. When the recursive (default) merge strategy is used, this allows rebase to be aware of renames on the upstream side. ++ +Note that a rebase merge works by replaying each commit from the working +branch on top of the <upstream> branch. Because of this, when a merge +conflict happens, the side reported as 'ours' is the so-far rebased +series, starting with <upstream>, and 'theirs' is the working branch. In +other words, the sides are swapped. -s <strategy>:: --strategy=<strategy>:: Use the given merge strategy. - If there is no `-s` option, a built-in list of strategies - is used instead ('git-merge-recursive' when merging a single - head, 'git-merge-octopus' otherwise). This implies --merge. + If there is no `-s` option 'git-merge-recursive' is used + instead. This implies --merge. ++ +Because 'git-rebase' replays each commit from the working branch +on top of the <upstream> branch using the given strategy, using +the 'ours' strategy simply discards all patches from the <branch>, +which makes little sense. -q:: --quiet:: @@ -368,14 +378,17 @@ By replacing the command "pick" with the command "edit", you can tell the files and/or the commit message, amend the commit, and continue rebasing. +If you just want to edit the commit message for a commit, replace the +command "pick" with the command "reword". + If you want to fold two or more commits into one, replace the command "pick" with "squash" for the second and subsequent commit. If the commits had different authors, it will attribute the squashed commit to the author of the first commit. -In both cases, or when a "pick" does not succeed (because of merge -errors), the loop will stop to let you fix things, and you can continue -the loop with `git rebase --continue`. +'git-rebase' will stop when "pick" has been replaced with "edit" or +when a command fails due to merge errors. When you are done editing +and/or resolving conflicts you can continue with `git rebase --continue`. For example, if you want to reorder the last 5 commits, such that what was HEAD~4 becomes the new HEAD. To achieve that, you would call diff --git a/Documentation/git-receive-pack.txt b/Documentation/git-receive-pack.txt index 514f03c979..cb5f405280 100644 --- a/Documentation/git-receive-pack.txt +++ b/Documentation/git-receive-pack.txt @@ -20,7 +20,7 @@ The UI for the protocol is on the 'git-send-pack' side, and the program pair is meant to be used to push updates to remote repository. For pull operations, see linkgit:git-fetch-pack[1]. -The command allows for creation and fast forwarding of sha1 refs +The command allows for creation and fast-forwarding of sha1 refs (heads/tags) on the remote end (strictly speaking, it is the local end 'git-receive-pack' runs, but to the user who is sitting at the send-pack end, it is updating the remote. Confused?) diff --git a/Documentation/git-remote-helpers.txt b/Documentation/git-remote-helpers.txt index 173ee232f2..8beb42dbb9 100644 --- a/Documentation/git-remote-helpers.txt +++ b/Documentation/git-remote-helpers.txt @@ -34,15 +34,51 @@ Commands are given by the caller on the helper's standard input, one per line. value of the ref. A space-separated list of attributes follows the name; unrecognized attributes are ignored. After the complete list, outputs a blank line. ++ +If 'push' is supported this may be called as 'list for-push' +to obtain the current refs prior to sending one or more 'push' +commands to the helper. + +'option' <name> <value>:: + Set the transport helper option <name> to <value>. Outputs a + single line containing one of 'ok' (option successfully set), + 'unsupported' (option not recognized) or 'error <msg>' + (option <name> is supported but <value> is not correct + for it). Options should be set before other commands, + and may how those commands behave. ++ +Supported if the helper has the "option" capability. 'fetch' <sha1> <name>:: - Fetches the given object, writing the necessary objects to the - database. Outputs a blank line when the fetch is - complete. Only objects which were reported in the ref list - with a sha1 may be fetched this way. + Fetches the given object, writing the necessary objects + to the database. Fetch commands are sent in a batch, one + per line, and the batch is terminated with a blank line. + Outputs a single blank line when all fetch commands in the + same batch are complete. Only objects which were reported + in the ref list with a sha1 may be fetched this way. ++ +Optionally may output a 'lock <file>' line indicating a file under +GIT_DIR/objects/pack which is keeping a pack until refs can be +suitably updated. + Supported if the helper has the "fetch" capability. +'push' +<src>:<dst>:: + Pushes the given <src> commit or branch locally to the + remote branch described by <dst>. A batch sequence of + one or more push commands is terminated with a blank line. ++ +Zero or more protocol options may be entered after the last 'push' +command, before the batch's terminating blank line. ++ +When the push is complete, outputs one or more 'ok <dst>' or +'error <dst> <why>?' lines to indicate success or failure of +each pushed ref. The status report output is terminated by +a blank line. The option field <why> may be quoted in a C +style string if it contains an LF. ++ +Supported if the helper has the "push" capability. + If a fatal error occurs, the program writes the error message to stderr and exits. The caller should expect that a suitable error message has been printed if the child closes the connection without @@ -57,10 +93,49 @@ CAPABILITIES 'fetch':: This helper supports the 'fetch' command. +'option':: + This helper supports the option command. + +'push':: + This helper supports the 'push' command. + REF LIST ATTRIBUTES ------------------- -None are defined yet, but the caller must accept any which are supplied. +'for-push':: + The caller wants to use the ref list to prepare push + commands. A helper might chose to acquire the ref list by + opening a different type of connection to the destination. + +OPTIONS +------- +'option verbosity' <N>:: + Change the level of messages displayed by the helper. + When N is 0 the end-user has asked the process to be + quiet, and the helper should produce only error output. + N of 1 is the default level of verbosity, higher values + of N correspond to the number of -v flags passed on the + command line. + +'option progress' \{'true'|'false'\}:: + Enable (or disable) progress messages displayed by the + transport helper during a command. + +'option depth' <depth>:: + Deepen the history of a shallow repository. + +'option followtags' \{'true'|'false'\}:: + If enabled the helper should automatically fetch annotated + tag objects if the object the tag points at was transferred + during the fetch command. If the tag is not fetched by + the helper a second fetch command will usually be sent to + ask for the tag specifically. Some helpers may be able to + use this option to avoid a second network connection. + +'option dry-run' \{'true'|'false'\}: + If true, pretend the operation completed successfully, + but don't actually change any repository data. For most + helpers this only applies to the 'push', if supported. Documentation ------------- diff --git a/Documentation/git-replace.txt b/Documentation/git-replace.txt index 915cb77b29..65a0da508a 100644 --- a/Documentation/git-replace.txt +++ b/Documentation/git-replace.txt @@ -17,12 +17,36 @@ DESCRIPTION Adds a 'replace' reference in `.git/refs/replace/` The name of the 'replace' reference is the SHA1 of the object that is -replaced. The content of the replace reference is the SHA1 of the +replaced. The content of the 'replace' reference is the SHA1 of the replacement object. -Unless `-f` is given, the replace reference must not yet exist in +Unless `-f` is given, the 'replace' reference must not yet exist in `.git/refs/replace/` directory. +Replacement references will be used by default by all git commands +except those doing reachability traversal (prune, pack transfer and +fsck). + +It is possible to disable use of replacement references for any +command using the `--no-replace-objects` option just after 'git'. + +For example if commit 'foo' has been replaced by commit 'bar': + +------------------------------------------------ +$ git --no-replace-objects cat-file commit foo +------------------------------------------------ + +shows information about commit 'foo', while: + +------------------------------------------------ +$ git cat-file commit foo +------------------------------------------------ + +shows information about commit 'bar'. + +The 'GIT_NO_REPLACE_OBJECTS' environment variable can be set to +achieve the same effect as the `--no-replace-objects` option. + OPTIONS ------- -f:: @@ -54,6 +78,7 @@ SEE ALSO -------- linkgit:git-tag[1] linkgit:git-branch[1] +linkgit:git[1] Author ------ diff --git a/Documentation/git-reset.txt b/Documentation/git-reset.txt index 469cf6dbac..2d27e405a3 100644 --- a/Documentation/git-reset.txt +++ b/Documentation/git-reset.txt @@ -150,7 +150,7 @@ Automatic merge failed; fix conflicts and then commit the result. $ git reset --hard <2> $ git pull . topic/branch <3> Updating from 41223... to 13134... -Fast forward +Fast-forward $ git reset --hard ORIG_HEAD <4> ------------ + @@ -161,7 +161,7 @@ right now, so you decide to do that later. which is a synonym for "git reset --hard HEAD" clears the mess from the index file and the working tree. <3> Merge a topic branch into the current branch, which resulted -in a fast forward. +in a fast-forward. <4> But you decided that the topic branch is not ready for public consumption yet. "pull" or "merge" always leaves the original tip of the current branch in ORIG_HEAD, so resetting hard to it diff --git a/Documentation/git-send-email.txt b/Documentation/git-send-email.txt index 767cf4d4bd..8c482f40b9 100644 --- a/Documentation/git-send-email.txt +++ b/Documentation/git-send-email.txt @@ -60,8 +60,8 @@ The --bcc option must be repeated for each user you want on the bcc list. The --cc option must be repeated for each user you want on the cc list. --compose:: - Use $GIT_EDITOR, core.editor, $VISUAL, or $EDITOR to edit an - introductory message for the patch series. + Invoke a text editor (see GIT_EDITOR in linkgit:git-var[1]) + to edit an introductory message for the patch series. + When '--compose' is used, git send-email will use the From, Subject, and In-Reply-To headers specified in the message. If the body of the message @@ -108,9 +108,10 @@ Sending --envelope-sender=<address>:: Specify the envelope sender used to send the emails. This is useful if your default address is not the address that is - subscribed to a list. If you use the sendmail binary, you must have - suitable privileges for the -f parameter. Default is the value of - the 'sendemail.envelopesender' configuration variable; if that is + subscribed to a list. In order to use the 'From' address, set the + value to "auto". If you use the sendmail binary, you must have + suitable privileges for the -f parameter. Default is the value of the + 'sendemail.envelopesender' configuration variable; if that is unspecified, choosing the envelope sender is left to your MTA. --smtp-encryption=<encryption>:: diff --git a/Documentation/git-send-pack.txt b/Documentation/git-send-pack.txt index 399821832c..5a04c6eaf7 100644 --- a/Documentation/git-send-pack.txt +++ b/Documentation/git-send-pack.txt @@ -105,11 +105,11 @@ name. See linkgit:git-rev-parse[1]. Without '--force', the <src> ref is stored at the remote only if <dst> does not exist, or <dst> is a proper subset (i.e. an -ancestor) of <src>. This check, known as "fast forward check", +ancestor) of <src>. This check, known as "fast-forward check", is performed in order to avoid accidentally overwriting the remote ref and lose other peoples' commits from there. -With '--force', the fast forward check is disabled for all refs. +With '--force', the fast-forward check is disabled for all refs. Optionally, a <ref> parameter can be prefixed with a plus '+' sign to disable the fast-forward check only on that ref. diff --git a/Documentation/git-show-ref.txt b/Documentation/git-show-ref.txt index f4429bdc68..70f400b266 100644 --- a/Documentation/git-show-ref.txt +++ b/Documentation/git-show-ref.txt @@ -8,7 +8,7 @@ git-show-ref - List references in a local repository SYNOPSIS -------- [verse] -'git show-ref' [-q|--quiet] [--verify] [-h|--head] [-d|--dereference] +'git show-ref' [-q|--quiet] [--verify] [--head] [-d|--dereference] [-s|--hash[=<n>]] [--abbrev[=<n>]] [--tags] [--heads] [--] <pattern>... 'git show-ref' --exclude-existing[=<pattern>] < ref-list @@ -30,7 +30,6 @@ the `.git` directory. OPTIONS ------- --h:: --head:: Show the HEAD reference. diff --git a/Documentation/git-stash.txt b/Documentation/git-stash.txt index fafe728f89..3f14b727b8 100644 --- a/Documentation/git-stash.txt +++ b/Documentation/git-stash.txt @@ -78,8 +78,7 @@ stash@{1}: On master: 9cc0589... Add git-stash ---------------------------------------------------------------- + The command takes options applicable to the 'git-log' -command to control what is shown and how. If no options are set, the -default is `-n 10`. See linkgit:git-log[1]. +command to control what is shown and how. See linkgit:git-log[1]. show [<stash>]:: diff --git a/Documentation/git-submodule.txt b/Documentation/git-submodule.txt index 5ccdd18c89..4ef70c42eb 100644 --- a/Documentation/git-submodule.txt +++ b/Documentation/git-submodule.txt @@ -10,7 +10,7 @@ SYNOPSIS -------- [verse] 'git submodule' [--quiet] add [-b branch] - [--reference <repository>] [--] <repository> <path> + [--reference <repository>] [--] <repository> [<path>] 'git submodule' [--quiet] status [--cached] [--recursive] [--] [<path>...] 'git submodule' [--quiet] init [--] [<path>...] 'git submodule' [--quiet] update [--init] [-N|--no-fetch] [--rebase] @@ -69,7 +69,11 @@ add:: to the changeset to be committed next to the current project: the current project is termed the "superproject". + -This requires two arguments: <repository> and <path>. +This requires at least one argument: <repository>. The optional +argument <path> is the relative location for the cloned submodule +to exist in the superproject. If <path> is not given, the +"humanish" part of the source repository is used ("repo" for +"/path/to/repo.git" and "foo" for "host.xz:foo/.git"). + <repository> is the URL of the new submodule's origin repository. This may be either an absolute URL, or (if it begins with ./ diff --git a/Documentation/git-svn.txt b/Documentation/git-svn.txt index 1812890a7e..4cdca0d874 100644 --- a/Documentation/git-svn.txt +++ b/Documentation/git-svn.txt @@ -320,6 +320,13 @@ Any other arguments are passed directly to 'git log' directories. The output is suitable for appending to the $GIT_DIR/info/exclude file. +'mkdirs':: + Attempts to recreate empty directories that core git cannot track + based on information in $GIT_DIR/svn/<refname>/unhandled.log files. + Empty directories are automatically recreated when using + "git svn clone" and "git svn rebase", so "mkdirs" is intended + for use after commands like "git checkout" or "git reset". + 'commit-diff':: Commits the diff of two tree-ish arguments from the command-line. This command does not rely on being inside an `git svn @@ -735,6 +742,16 @@ merges you've made. Furthermore, if you merge or pull from a git branch that is a mirror of an SVN branch, 'dcommit' may commit to the wrong branch. +If you do merge, note the following rule: 'git svn dcommit' will +attempt to commit on top of the SVN commit named in +------------------------------------------------------------------------ +git log --grep=^git-svn-id: --first-parent -1 +------------------------------------------------------------------------ +You 'must' therefore ensure that the most recent commit of the branch +you want to dcommit to is the 'first' parent of the merge. Chaos will +ensue otherwise, especially if the first parent is an older commit on +the same SVN branch. + 'git clone' does not clone branches under the refs/remotes/ hierarchy or any 'git svn' metadata, or config. So repositories created and managed with using 'git svn' should use 'rsync' for cloning, if cloning is to be done diff --git a/Documentation/git-update-index.txt b/Documentation/git-update-index.txt index 25e0bbea86..6052484ab9 100644 --- a/Documentation/git-update-index.txt +++ b/Documentation/git-update-index.txt @@ -99,6 +99,10 @@ in the index e.g. when merging in a commit; thus, in case the assumed-untracked file is changed upstream, you will need to handle the situation manually. +--really-refresh:: + Like '--refresh', but checks stat information unconditionally, + without regard to the "assume unchanged" setting. + -g:: --again:: Runs 'git-update-index' itself on the paths whose index @@ -308,7 +312,7 @@ Configuration ------------- The command honors `core.filemode` configuration variable. If -your repository is on an filesystem whose executable bits are +your repository is on a filesystem whose executable bits are unreliable, this should be set to 'false' (see linkgit:git-config[1]). This causes the command to ignore differences in file modes recorded in the index and the file mode on the filesystem if they differ only on diff --git a/Documentation/git-var.txt b/Documentation/git-var.txt index e2f4c0901b..ef6aa81872 100644 --- a/Documentation/git-var.txt +++ b/Documentation/git-var.txt @@ -36,6 +36,20 @@ GIT_AUTHOR_IDENT:: GIT_COMMITTER_IDENT:: The person who put a piece of code into git. +GIT_EDITOR:: + Text editor for use by git commands. The value is meant to be + interpreted by the shell when it is used. Examples: `~/bin/vi`, + `$SOME_ENVIRONMENT_VARIABLE`, `"C:\Program Files\Vim\gvim.exe" + --nofork`. The order of preference is the `$GIT_EDITOR` + environment variable, then `core.editor` configuration, then + `$VISUAL`, then `$EDITOR`, and then finally 'vi'. + +GIT_PAGER:: + Text viewer for use by git commands (e.g., 'less'). The value + is meant to be interpreted by the shell. The order of preference + is the `$GIT_PAGER` environment variable, then `core.pager` + configuration, then `$PAGER`, and then finally 'less'. + Diagnostics ----------- You don't exist. Go away!:: diff --git a/Documentation/git.txt b/Documentation/git.txt index ff31095093..51ca39291f 100644 --- a/Documentation/git.txt +++ b/Documentation/git.txt @@ -10,7 +10,7 @@ SYNOPSIS -------- [verse] 'git' [--version] [--exec-path[=GIT_EXEC_PATH]] [--html-path] - [-p|--paginate|--no-pager] + [-p|--paginate|--no-pager] [--no-replace-objects] [--bare] [--git-dir=GIT_DIR] [--work-tree=GIT_WORK_TREE] [--help] COMMAND [ARGS] @@ -244,6 +244,10 @@ help ...`. environment is not set, it is set to the current working directory. +--no-replace-objects:: + Do not use replacement refs to replace git objects. See + linkgit:git-replace[1] for more information. + FURTHER DOCUMENTATION --------------------- diff --git a/Documentation/gitcore-tutorial.txt b/Documentation/gitcore-tutorial.txt index 0382d2c0ad..f762dca440 100644 --- a/Documentation/gitcore-tutorial.txt +++ b/Documentation/gitcore-tutorial.txt @@ -185,7 +185,7 @@ object is. git will tell you that you have a "blob" object (i.e., just a regular file), and you can see the contents with ---------------- -$ git cat-file "blob" 557db03 +$ git cat-file blob 557db03 ---------------- which will print out "Hello World". The object `557db03` is nothing @@ -993,7 +993,7 @@ would be different) ---------------- Updating from ae3a2da... to a80b4aa.... -Fast forward (no commit created; -m option ignored) +Fast-forward (no commit created; -m option ignored) example | 1 + hello | 1 + 2 files changed, 2 insertions(+), 0 deletions(-) @@ -1003,7 +1003,7 @@ Because your branch did not contain anything more than what had already been merged into the `master` branch, the merge operation did not actually do a merge. Instead, it just updated the top of the tree of your branch to that of the `master` branch. This is -often called 'fast forward' merge. +often called 'fast-forward' merge. You can run `gitk \--all` again to see how the commit ancestry looks like, or run 'show-branch', which tells you this. @@ -1186,9 +1186,9 @@ $ git show-branch * [master] Some fun. ! [mybranch] Some work. -- - + [mybranch] Some work. * [master] Some fun. -*+ [mybranch^] New day. + + [mybranch] Some work. +*+ [master^] Initial commit ------------ Now we are ready to experiment with the merge by hand. @@ -1204,11 +1204,11 @@ $ mb=$(git merge-base HEAD mybranch) The command writes the commit object name of the common ancestor to the standard output, so we captured its output to a variable, because we will be using it in the next step. By the way, the common -ancestor commit is the "New day." commit in this case. You can +ancestor commit is the "Initial commit" commit in this case. You can tell it by: ------------ -$ git name-rev $mb +$ git name-rev --name-only --tags $mb my-first-tag ------------ @@ -1237,8 +1237,8 @@ inspect the index file with this command: ------------ $ git ls-files --stage 100644 7f8b141b65fdcee47321e399a2598a235a032422 0 example -100644 263414f423d0e4d70dae8fe53fa34614ff3e2860 1 hello -100644 06fa6a24256dc7e560efa5687fa84b51f0263c3a 2 hello +100644 557db03de997c86a4a028e1ebd3a1ceb225be238 1 hello +100644 ba42a2a96e3027f3333e13ede4ccf4498c3ae942 2 hello 100644 cc44c73eb783565da5831b4d820c962954019b69 3 hello ------------ @@ -1253,8 +1253,8 @@ To look at only non-zero stages, use `\--unmerged` flag: ------------ $ git ls-files --unmerged -100644 263414f423d0e4d70dae8fe53fa34614ff3e2860 1 hello -100644 06fa6a24256dc7e560efa5687fa84b51f0263c3a 2 hello +100644 557db03de997c86a4a028e1ebd3a1ceb225be238 1 hello +100644 ba42a2a96e3027f3333e13ede4ccf4498c3ae942 2 hello 100644 cc44c73eb783565da5831b4d820c962954019b69 3 hello ------------ @@ -1283,8 +1283,8 @@ the working tree.. This can be seen if you run `ls-files ------------ $ git ls-files --stage 100644 7f8b141b65fdcee47321e399a2598a235a032422 0 example -100644 263414f423d0e4d70dae8fe53fa34614ff3e2860 1 hello -100644 06fa6a24256dc7e560efa5687fa84b51f0263c3a 2 hello +100644 557db03de997c86a4a028e1ebd3a1ceb225be238 1 hello +100644 ba42a2a96e3027f3333e13ede4ccf4498c3ae942 2 hello 100644 cc44c73eb783565da5831b4d820c962954019b69 3 hello ------------ diff --git a/Documentation/githooks.txt b/Documentation/githooks.txt index 3ab4f4d42c..29eeae77ca 100644 --- a/Documentation/githooks.txt +++ b/Documentation/githooks.txt @@ -229,7 +229,7 @@ from updating that ref. This hook can be used to prevent 'forced' update on certain refs by making sure that the object name is a commit object that is a descendant of the commit object named by the old object name. -That is, to enforce a "fast forward only" policy. +That is, to enforce a "fast-forward only" policy. It could also be used to log the old..new status. However, it does not know the entire set of branches, so it would end up diff --git a/Documentation/gitworkflows.txt b/Documentation/gitworkflows.txt index 91c0eea890..065441df64 100644 --- a/Documentation/gitworkflows.txt +++ b/Documentation/gitworkflows.txt @@ -229,7 +229,7 @@ To verify that 'master' is indeed a superset of 'maint', use git log: .Verify 'master' is a superset of 'maint' [caption="Recipe: "] ===================================== -git log master..maint +`git log master..maint` ===================================== This command should not list any commits. Otherwise, check out diff --git a/Documentation/glossary-content.txt b/Documentation/glossary-content.txt index 43d84d15e9..1f029f8aa0 100644 --- a/Documentation/glossary-content.txt +++ b/Documentation/glossary-content.txt @@ -124,7 +124,7 @@ to point at the new commit. An evil merge is a <<def_merge,merge>> that introduces changes that do not appear in any <<def_parent,parent>>. -[[def_fast_forward]]fast forward:: +[[def_fast_forward]]fast-forward:: A fast-forward is a special type of <<def_merge,merge>> where you have a <<def_revision,revision>> and you are "merging" another <<def_branch,branch>>'s changes that happen to be a descendant of what @@ -220,7 +220,7 @@ to point at the new commit. conflict, manual intervention may be required to complete the merge. + -As a noun: unless it is a <<def_fast_forward,fast forward>>, a +As a noun: unless it is a <<def_fast_forward,fast-forward>>, a successful merge results in the creation of a new <<def_commit,commit>> representing the result of the merge, and having as <<def_parent,parents>> the tips of the merged <<def_branch,branches>>. diff --git a/Documentation/howto/maintain-git.txt b/Documentation/howto/maintain-git.txt index 4357e26913..d527b30770 100644 --- a/Documentation/howto/maintain-git.txt +++ b/Documentation/howto/maintain-git.txt @@ -59,7 +59,7 @@ The policy. not yet pass the criteria set for 'next'. - The tips of 'master', 'maint' and 'next' branches will always - fast forward, to allow people to build their own + fast-forward, to allow people to build their own customization on top of them. - Usually 'master' contains all of 'maint', 'next' contains all diff --git a/Documentation/howto/revert-branch-rebase.txt b/Documentation/howto/revert-branch-rebase.txt index e70d8a31e7..8c32da6deb 100644 --- a/Documentation/howto/revert-branch-rebase.txt +++ b/Documentation/howto/revert-branch-rebase.txt @@ -85,7 +85,7 @@ Fortunately I did not have to; what I have in the current branch ------------------------------------------------ $ git checkout master -$ git merge revert-c99 ;# this should be a fast forward +$ git merge revert-c99 ;# this should be a fast-forward Updating from 10d781b9caa4f71495c7b34963bef137216f86a8 to e3a693c... cache.h | 8 ++++---- commit.c | 2 +- @@ -95,7 +95,7 @@ Updating from 10d781b9caa4f71495c7b34963bef137216f86a8 to e3a693c... 5 files changed, 8 insertions(+), 8 deletions(-) ------------------------------------------------ -There is no need to redo the test at this point. We fast forwarded +There is no need to redo the test at this point. We fast-forwarded and we know 'master' matches 'revert-c99' exactly. In fact: ------------------------------------------------ diff --git a/Documentation/howto/update-hook-example.txt b/Documentation/howto/update-hook-example.txt index 697d918885..b7f8d416d6 100644 --- a/Documentation/howto/update-hook-example.txt +++ b/Documentation/howto/update-hook-example.txt @@ -76,7 +76,7 @@ case "$1" in if expr "$2" : '0*$' >/dev/null; then info "The branch '$1' is new..." else - # updating -- make sure it is a fast forward + # updating -- make sure it is a fast-forward mb=$(git-merge-base "$2" "$3") case "$mb,$2" in "$2,$mb") info "Update is fast-forward" ;; diff --git a/Documentation/merge-config.txt b/Documentation/merge-config.txt index c0f96e7070..a403155052 100644 --- a/Documentation/merge-config.txt +++ b/Documentation/merge-config.txt @@ -23,7 +23,7 @@ merge.tool:: Controls which merge resolution program is used by linkgit:git-mergetool[1]. Valid built-in values are: "kdiff3", "tkdiff", "meld", "xxdiff", "emerge", "vimdiff", "gvimdiff", - "diffuse", "ecmerge", "tortoisemerge", "araxis", and + "diffuse", "ecmerge", "tortoisemerge", "p4merge", "araxis" and "opendiff". Any other value is treated is custom merge tool and there must be a corresponding mergetool.<tool>.cmd option. diff --git a/Documentation/merge-options.txt b/Documentation/merge-options.txt index 48d04a5d88..fec3394305 100644 --- a/Documentation/merge-options.txt +++ b/Documentation/merge-options.txt @@ -49,6 +49,11 @@ merge. With --no-squash perform the merge and commit the result. This option can be used to override --squash. +--ff-only:: + Refuse to merge and exit with a non-zero status unless the + current `HEAD` is already up-to-date or the merge can be + resolved as a fast-forward. + -s <strategy>:: --strategy=<strategy>:: Use the given merge strategy; can be supplied more than diff --git a/Documentation/merge-strategies.txt b/Documentation/merge-strategies.txt index 4365b7e842..42910a3d5e 100644 --- a/Documentation/merge-strategies.txt +++ b/Documentation/merge-strategies.txt @@ -29,8 +29,9 @@ octopus:: pulling or merging more than one branch. ours:: - This resolves any number of heads, but the result of the - merge is always the current branch head. It is meant to + This resolves any number of heads, but the resulting tree of the + merge is always that of the current branch head, effectively + ignoring all changes from all other branches. It is meant to be used to supersede old development history of side branches. diff --git a/Documentation/pretty-formats.txt b/Documentation/pretty-formats.txt index 2a845b1e57..53a9168ba7 100644 --- a/Documentation/pretty-formats.txt +++ b/Documentation/pretty-formats.txt @@ -123,6 +123,10 @@ The placeholders are: - '%s': subject - '%f': sanitized subject line, suitable for a filename - '%b': body +- '%N': commit notes +- '%gD': reflog selector, e.g., `refs/stash@\{1\}` +- '%gd': shortened reflog selector, e.g., `stash@\{1\}` +- '%gs': reflog subject - '%Cred': switch color to red - '%Cgreen': switch color to green - '%Cblue': switch color to blue @@ -131,6 +135,22 @@ The placeholders are: - '%m': left, right or boundary mark - '%n': newline - '%x00': print a byte from a hex code +- '%w([<w>[,<i1>[,<i2>]]])': switch line wrapping, like the -w option of + linkgit:git-shortlog[1]. + +NOTE: Some placeholders may depend on other options given to the +revision traversal engine. For example, the `%g*` reflog options will +insert an empty string unless we are traversing reflog entries (e.g., by +`git log -g`). The `%d` placeholder will use the "short" decoration +format if `--decorate` was not already provided on the command line. + +If you add a `{plus}` (plus sign) after '%' of a placeholder, a line-feed +is inserted immediately before the expansion if and only if the +placeholder expands to a non-empty string. + +If you add a `-` (minus sign) after '%' of a placeholder, line-feeds that +immediately precede the expansion are deleted if and only if the +placeholder expands to an empty string. * 'tformat:' + diff --git a/Documentation/pt_BR/gittutorial.txt b/Documentation/pt_BR/gittutorial.txt index 81e7ad7df4..beba065252 100644 --- a/Documentation/pt_BR/gittutorial.txt +++ b/Documentation/pt_BR/gittutorial.txt @@ -1,15 +1,15 @@ gittutorial(7) ============== -NAME +NOME ---- gittutorial - Um tutorial de introdução ao git (para versão 1.5.1 ou mais nova) -SYNOPSIS +SINOPSE -------- git * -DESCRIPTION +DESCRIÇÃO ----------- Este tutorial explica como importar um novo projeto para o git, @@ -64,11 +64,11 @@ Git irá responder Initialized empty Git repository in .git/ ------------------------------------------------ -Você agora iniciou seu diretório de trabalho--você deve ter notado um -novo diretório criado, com o nome de ".git". +Agora que você iniciou seu diretório de trabalho, você deve ter notado que um +novo diretório foi criado com o nome de ".git". A seguir, diga ao git para gravar um instantâneo do conteúdo de todos os -arquivos sob o diretório corrente (note o '.'), com 'git-add': +arquivos sob o diretório atual (note o '.'), com 'git-add': ------------------------------------------------ $ git add . @@ -126,8 +126,8 @@ mudanças com: $ git commit ------------------------------------------------ -Isto irá novamente te pedir por uma mensagem descrevendo a mudança, e, -então, gravar a nova versão do projeto. +Ao executar esse comando, ele irá te pedir uma mensagem descrevendo a mudança, +e, então, irá gravar a nova versão do projeto. Alternativamente, ao invés de executar 'git-add' antes, você pode usar @@ -143,7 +143,7 @@ idéia começar a mensagem com uma simples e curta (menos de 50 caracteres) linha sumarizando a mudança, seguida de uma linha em branco e, então, uma descrição mais detalhada. Ferramentas que transformam commits em email, por exemplo, usam a primeira linha no campo de -cabeçalho Subject: e o resto no corpo. +cabeçalho "Subject:" e o resto no corpo. Git rastreia conteúdo, não arquivos ---------------------------- @@ -155,7 +155,7 @@ usado tanto para arquivos novos e arquivos recentemente modificados, e em ambos os casos, ele tira o instantâneo dos arquivos dados e armazena o conteúdo no índice, pronto para inclusão do próximo commit. -Visualizando história do projeto +Visualizando a história do projeto ----------------------- Em qualquer ponto você pode visualizar a história das suas mudanças @@ -165,7 +165,7 @@ usando $ git log ------------------------------------------------ -Se você também quer ver a diferença completa a cada passo, use +Se você também quiser ver a diferença completa a cada passo, use ------------------------------------------------ $ git log -p diff --git a/Documentation/pull-fetch-param.txt b/Documentation/pull-fetch-param.txt index f9811f2473..0551ebdfaf 100644 --- a/Documentation/pull-fetch-param.txt +++ b/Documentation/pull-fetch-param.txt @@ -4,6 +4,13 @@ (see the section <<URLS,GIT URLS>> below) or the name of a remote (see the section <<REMOTES,REMOTES>> below). +ifndef::git-pull[] +<group>:: + A name referring to a list of repositories as the value + of remotes.<group> in the configuration file. + (See linkgit:git-config[1]). +endif::git-pull[] + <refspec>:: The format of a <refspec> parameter is an optional plus `{plus}`, followed by the source ref <src>, followed @@ -11,9 +18,9 @@ + The remote ref that matches <src> is fetched, and if <dst> is not empty string, the local -ref that matches it is fast forwarded using <src>. +ref that matches it is fast-forwarded using <src>. If the optional plus `+` is used, the local ref -is updated even if it does not result in a fast forward +is updated even if it does not result in a fast-forward update. + [NOTE] diff --git a/Documentation/rev-list-options.txt b/Documentation/rev-list-options.txt index bf66116d61..1f57aed337 100644 --- a/Documentation/rev-list-options.txt +++ b/Documentation/rev-list-options.txt @@ -243,12 +243,23 @@ endif::git-rev-list[] Pretend as if all the refs in `$GIT_DIR/refs/remotes` are listed on the command line as '<commit>'. -ifdef::git-rev-list[] +ifndef::git-rev-list[] +--bisect:: + + Pretend as if the bad bisection ref `$GIT_DIR/refs/bisect/bad` + was listed and as if it was followed by `--not` and the good + bisection refs `$GIT_DIR/refs/bisect/good-*` on the command + line. +endif::git-rev-list[] + --stdin:: In addition to the '<commit>' listed on the command - line, read them from the standard input. + line, read them from the standard input. If a '--' separator is + seen, stop reading commits and start reading paths to limit the + result. +ifdef::git-rev-list[] --quiet:: Don't print anything to standard output. This form @@ -536,7 +547,11 @@ Bisection Helpers --bisect:: Limit output to the one commit object which is roughly halfway between -the included and excluded commits. Thus, if +included and excluded commits. Note that the bad bisection ref +`$GIT_DIR/refs/bisect/bad` is added to the included commits (if it +exists) and the good bisection refs `$GIT_DIR/refs/bisect/good-*` are +added to the excluded commits (if they exist). Thus, supposing there +are no refs in `$GIT_DIR/refs/bisect/`, if ----------------------------------------------------------------------- $ git rev-list --bisect foo ^bar ^baz @@ -556,22 +571,24 @@ one. --bisect-vars:: -This calculates the same as `--bisect`, but outputs text ready -to be eval'ed by the shell. These lines will assign the name of -the midpoint revision to the variable `bisect_rev`, and the -expected number of commits to be tested after `bisect_rev` is -tested to `bisect_nr`, the expected number of commits to be -tested if `bisect_rev` turns out to be good to `bisect_good`, -the expected number of commits to be tested if `bisect_rev` -turns out to be bad to `bisect_bad`, and the number of commits -we are bisecting right now to `bisect_all`. +This calculates the same as `--bisect`, except that refs in +`$GIT_DIR/refs/bisect/` are not used, and except that this outputs +text ready to be eval'ed by the shell. These lines will assign the +name of the midpoint revision to the variable `bisect_rev`, and the +expected number of commits to be tested after `bisect_rev` is tested +to `bisect_nr`, the expected number of commits to be tested if +`bisect_rev` turns out to be good to `bisect_good`, the expected +number of commits to be tested if `bisect_rev` turns out to be bad to +`bisect_bad`, and the number of commits we are bisecting right now to +`bisect_all`. --bisect-all:: This outputs all the commit objects between the included and excluded commits, ordered by their distance to the included and excluded -commits. The farthest from them is displayed first. (This is the only -one displayed by `--bisect`.) +commits. Refs in `$GIT_DIR/refs/bisect/` are not used. The farthest +from them is displayed first. (This is the only one displayed by +`--bisect`.) + This is useful because it makes it easy to choose a good commit to test when you want to avoid to test some of them for some reason (they diff --git a/Documentation/technical/pack-protocol.txt b/Documentation/technical/pack-protocol.txt index 9cd48b4859..7950eeeda4 100644 --- a/Documentation/technical/pack-protocol.txt +++ b/Documentation/technical/pack-protocol.txt @@ -1,41 +1,494 @@ -Pack transfer protocols -======================= - -There are two Pack push-pull protocols. - -upload-pack (S) | fetch/clone-pack (C) protocol: - - # Tell the puller what commits we have and what their names are - S: SHA1 name - S: ... - S: SHA1 name - S: # flush -- it's your turn - # Tell the pusher what commits we want, and what we have - C: want name - C: .. - C: want name - C: have SHA1 - C: have SHA1 - C: ... - C: # flush -- occasionally ask "had enough?" - S: NAK - C: have SHA1 - C: ... - C: have SHA1 - S: ACK - C: done - S: XXXXXXX -- packfile contents. - -send-pack | receive-pack protocol. - - # Tell the pusher what commits we have and what their names are - C: SHA1 name - C: ... - C: SHA1 name - C: # flush -- it's your turn - # Tell the puller what the pusher has - S: old-SHA1 new-SHA1 name - S: old-SHA1 new-SHA1 name - S: ... - S: # flush -- done with the list - S: XXXXXXX --- packfile contents. +Packfile transfer protocols +=========================== + +Git supports transferring data in packfiles over the ssh://, git:// and +file:// transports. There exist two sets of protocols, one for pushing +data from a client to a server and another for fetching data from a +server to a client. All three transports (ssh, git, file) use the same +protocol to transfer data. + +The processes invoked in the canonical Git implementation are 'upload-pack' +on the server side and 'fetch-pack' on the client side for fetching data; +then 'receive-pack' on the server and 'send-pack' on the client for pushing +data. The protocol functions to have a server tell a client what is +currently on the server, then for the two to negotiate the smallest amount +of data to send in order to fully update one or the other. + +Transports +---------- +There are three transports over which the packfile protocol is +initiated. The Git transport is a simple, unauthenticated server that +takes the command (almost always 'upload-pack', though Git +servers can be configured to be globally writable, in which 'receive- +pack' initiation is also allowed) with which the client wishes to +communicate and executes it and connects it to the requesting +process. + +In the SSH transport, the client just runs the 'upload-pack' +or 'receive-pack' process on the server over the SSH protocol and then +communicates with that invoked process over the SSH connection. + +The file:// transport runs the 'upload-pack' or 'receive-pack' +process locally and communicates with it over a pipe. + +Git Transport +------------- + +The Git transport starts off by sending the command and repository +on the wire using the pkt-line format, followed by a NUL byte and a +hostname paramater, terminated by a NUL byte. + + 0032git-upload-pack /project.git\0host=myserver.com\0 + +-- + git-proto-request = request-command SP pathname NUL [ host-parameter NUL ] + request-command = "git-upload-pack" / "git-receive-pack" / + "git-upload-archive" ; case sensitive + pathname = *( %x01-ff ) ; exclude NUL + host-parameter = "host=" hostname [ ":" port ] +-- + +Only host-parameter is allowed in the git-proto-request. Clients +MUST NOT attempt to send additional parameters. It is used for the +git-daemon name based virtual hosting. See --interpolated-path +option to git daemon, with the %H/%CH format characters. + +Basically what the Git client is doing to connect to an 'upload-pack' +process on the server side over the Git protocol is this: + + $ echo -e -n \ + "0039git-upload-pack /schacon/gitbook.git\0host=example.com\0" | + nc -v example.com 9418 + + +SSH Transport +------------- + +Initiating the upload-pack or receive-pack processes over SSH is +executing the binary on the server via SSH remote execution. +It is basically equivalent to running this: + + $ ssh git.example.com "git-upload-pack '/project.git'" + +For a server to support Git pushing and pulling for a given user over +SSH, that user needs to be able to execute one or both of those +commands via the SSH shell that they are provided on login. On some +systems, that shell access is limited to only being able to run those +two commands, or even just one of them. + +In an ssh:// format URI, it's absolute in the URI, so the '/' after +the host name (or port number) is sent as an argument, which is then +read by the remote git-upload-pack exactly as is, so it's effectively +an absolute path in the remote filesystem. + + git clone ssh://user@example.com/project.git + | + v + ssh user@example.com "git-upload-pack '/project.git'" + +In a "user@host:path" format URI, its relative to the user's home +directory, because the Git client will run: + + git clone user@example.com:project.git + | + v + ssh user@example.com "git-upload-pack 'project.git'" + +The exception is if a '~' is used, in which case +we execute it without the leading '/'. + + ssh://user@example.com/~alice/project.git, + | + v + ssh user@example.com "git-upload-pack '~alice/project.git'" + +A few things to remember here: + +- The "command name" is spelled with dash (e.g. git-upload-pack), but + this can be overridden by the client; + +- The repository path is always quoted with single quotes. + +Fetching Data From a Server +=========================== + +When one Git repository wants to get data that a second repository +has, the first can 'fetch' from the second. This operation determines +what data the server has that the client does not then streams that +data down to the client in packfile format. + + +Reference Discovery +------------------- + +When the client initially connects the server will immediately respond +with a listing of each reference it has (all branches and tags) along +with the object name that each reference currently points to. + + $ echo -e -n "0039git-upload-pack /schacon/gitbook.git\0host=example.com\0" | + nc -v example.com 9418 + 00887217a7c7e582c46cec22a130adf4b9d7d950fba0 HEAD\0multi_ack thin-pack side-band side-band-64k ofs-delta shallow no-progress include-tag + 00441d3fcd5ced445d1abc402225c0b8a1299641f497 refs/heads/integration + 003f7217a7c7e582c46cec22a130adf4b9d7d950fba0 refs/heads/master + 003cb88d2441cac0977faf98efc80305012112238d9d refs/tags/v0.9 + 003c525128480b96c89e6418b1e40909bf6c5b2d580f refs/tags/v1.0 + 003fe92df48743b7bc7d26bcaabfddde0a1e20cae47c refs/tags/v1.0^{} + 0000 + +Server SHOULD terminate each non-flush line using LF ("\n") terminator; +client MUST NOT complain if there is no terminator. + +The returned response is a pkt-line stream describing each ref and +its current value. The stream MUST be sorted by name according to +the C locale ordering. + +If HEAD is a valid ref, HEAD MUST appear as the first advertised +ref. If HEAD is not a valid ref, HEAD MUST NOT appear in the +advertisement list at all, but other refs may still appear. + +The stream MUST include capability declarations behind a NUL on the +first ref. The peeled value of a ref (that is "ref^{}") MUST be +immediately after the ref itself, if presented. A conforming server +MUST peel the ref if its an annotated tag. + +---- + advertised-refs = (no-refs / list-of-refs) + flush-pkt + + no-refs = PKT-LINE(zero-id SP "capabilities^{}" + NUL capability-list LF) + + list-of-refs = first-ref *other-ref + first-ref = PKT-LINE(obj-id SP refname + NUL capability-list LF) + + other-ref = PKT-LINE(other-tip / other-peeled) + other-tip = obj-id SP refname LF + other-peeled = obj-id SP refname "^{}" LF + + capability-list = capability *(SP capability) + capability = 1*(LC_ALPHA / DIGIT / "-" / "_") + LC_ALPHA = %x61-7A +---- + +Server and client MUST use lowercase for obj-id, both MUST treat obj-id +as case-insensitive. + +See protocol-capabilities.txt for a list of allowed server capabilities +and descriptions. + +Packfile Negotiation +-------------------- +After reference and capabilities discovery, the client can decide +to terminate the connection by sending a flush-pkt, telling the +server it can now gracefully terminate (as happens with the ls-remote +command) or it can enter the negotiation phase, where the client and +server determine what the minimal packfile necessary for transport is. + +Once the client has the initial list of references that the server +has, as well as the list of capabilities, it will begin telling the +server what objects it wants and what objects it has, so the server +can make a packfile that only contains the objects that the client needs. +The client will also send a list of the capabilities it wants to be in +effect, out of what the server said it could do with the first 'want' line. + +---- + upload-request = want-list + have-list + compute-end + + want-list = first-want + *additional-want + flush-pkt + + first-want = PKT-LINE("want" SP obj-id SP capability-list LF) + additional-want = PKT-LINE("want" SP obj-id LF) + + have-list = *have-line + have-line = PKT-LINE("have" SP obj-id LF) + compute-end = flush-pkt / PKT-LINE("done") +---- + +Clients MUST send all the obj-ids it wants from the reference +discovery phase as 'want' lines. Clients MUST send at least one +'want' command in the request body. Clients MUST NOT mention an +obj-id in a 'want' command which did not appear in the response +obtained through ref discovery. + +If client is requesting a shallow clone, it will now send a 'deepen' +line with the depth it is requesting. + +Once all the "want"s (and optional 'deepen') are transferred, +clients MUST send a flush-pkt. If the client has all the references +on the server, client flushes and disconnects. + +TODO: shallow/unshallow response and document the deepen command in the ABNF. + +Now the client will send a list of the obj-ids it has using 'have' +lines. In multi_ack mode, the canonical implementation will send up +to 32 of these at a time, then will send a flush-pkt. The canonical +implementation will skip ahead and send the next 32 immediately, +so that there is always a block of 32 "in-flight on the wire" at a +time. + +If the server reads 'have' lines, it then will respond by ACKing any +of the obj-ids the client said it had that the server also has. The +server will ACK obj-ids differently depending on which ack mode is +chosen by the client. + +In multi_ack mode: + + * the server will respond with 'ACK obj-id continue' for any common + commits. + + * once the server has found an acceptable common base commit and is + ready to make a packfile, it will blindly ACK all 'have' obj-ids + back to the client. + + * the server will then send a 'NACK' and then wait for another response + from the client - either a 'done' or another list of 'have' lines. + +In multi_ack_detailed mode: + + * the server will differentiate the ACKs where it is signaling + that it is ready to send data with 'ACK obj-id ready' lines, and + signals the identified common commits with 'ACK obj-id common' lines. + +Without either multi_ack or multi_ack_detailed: + + * upload-pack sends "ACK obj-id" on the first common object it finds. + After that it says nothing until the client gives it a "done". + + * upload-pack sends "NAK" on a flush-pkt if no common object + has been found yet. If one has been found, and thus an ACK + was already sent, its silent on the flush-pkt. + +After the client has gotten enough ACK responses that it can determine +that the server has enough information to send an efficient packfile +(in the canonical implementation, this is determined when it has received +enough ACKs that it can color everything left in the --date-order queue +as common with the server, or the --date-order queue is empty), or the +client determines that it wants to give up (in the canonical implementation, +this is determined when the client sends 256 'have' lines without getting +any of them ACKed by the server - meaning there is nothing in common and +the server should just send all it's objects), then the client will send +a 'done' command. The 'done' command signals to the server that the client +is ready to receive it's packfile data. + +However, the 256 limit *only* turns on in the canonical client +implementation if we have received at least one "ACK %s continue" +during a prior round. This helps to ensure that at least one common +ancestor is found before we give up entirely. + +Once the 'done' line is read from the client, the server will either +send a final 'ACK obj-id' or it will send a 'NAK'. The server only sends +ACK after 'done' if there is at least one common base and multi_ack or +multi_ack_detailed is enabled. The server always sends NAK after 'done' +if there is no common base found. + +Then the server will start sending it's packfile data. + +---- + server-response = *ack_multi ack / nak + ack_multi = PKT-LINE("ACK" SP obj-id ack_status LF) + ack_status = "continue" / "common" / "ready" + ack = PKT-LINE("ACK SP obj-id LF) + nak = PKT-LINE("NAK" LF) +---- + +A simple clone may look like this (with no 'have' lines): + +---- + C: 0054want 74730d410fcb6603ace96f1dc55ea6196122532d\0multi_ack \ + side-band-64k ofs-delta\n + C: 0032want 7d1665144a3a975c05f1f43902ddaf084e784dbe\n + C: 0032want 5a3f6be755bbb7deae50065988cbfa1ffa9ab68a\n + C: 0032want 7e47fe2bd8d01d481f44d7af0531bd93d3b21c01\n + C: 0032want 74730d410fcb6603ace96f1dc55ea6196122532d\n + C: 0000 + C: 0009done\n + + S: 0008NAK\n + S: [PACKFILE] +---- + +An incremental update (fetch) response might look like this: + +---- + C: 0054want 74730d410fcb6603ace96f1dc55ea6196122532d\0multi_ack \ + side-band-64k ofs-delta\n + C: 0032want 7d1665144a3a975c05f1f43902ddaf084e784dbe\n + C: 0032want 5a3f6be755bbb7deae50065988cbfa1ffa9ab68a\n + C: 0000 + C: 0032have 7e47fe2bd8d01d481f44d7af0531bd93d3b21c01\n + C: [30 more have lines] + C: 0032have 74730d410fcb6603ace96f1dc55ea6196122532d\n + C: 0000 + + S: 003aACK 7e47fe2bd8d01d481f44d7af0531bd93d3b21c01 continue\n + S: 003aACK 74730d410fcb6603ace96f1dc55ea6196122532d continue\n + S: 0008NAK\n + + C: 0009done\n + + S: 003aACK 74730d410fcb6603ace96f1dc55ea6196122532d\n + S: [PACKFILE] +---- + + +Packfile Data +------------- + +Now that the client and server have finished negotiation about what +the minimal amount of data that needs to be sent to the client is, the server +will construct and send the required data in packfile format. + +See pack-format.txt for what the packfile itself actually looks like. + +If 'side-band' or 'side-band-64k' capabilities have been specified by +the client, the server will send the packfile data multiplexed. + +Each packet starting with the packet-line length of the amount of data +that follows, followed by a single byte specifying the sideband the +following data is coming in on. + +In 'side-band' mode, it will send up to 999 data bytes plus 1 control +code, for a total of up to 1000 bytes in a pkt-line. In 'side-band-64k' +mode it will send up to 65519 data bytes plus 1 control code, for a +total of up to 65520 bytes in a pkt-line. + +The sideband byte will be a '1', '2' or a '3'. Sideband '1' will contain +packfile data, sideband '2' will be used for progress information that the +client will generally print to stderr and sideband '3' is used for error +information. + +If no 'side-band' capability was specified, the server will stream the +entire packfile without multiplexing. + + +Pushing Data To a Server +======================== + +Pushing data to a server will invoke the 'receive-pack' process on the +server, which will allow the client to tell it which references it should +update and then send all the data the server will need for those new +references to be complete. Once all the data is received and validated, +the server will then update its references to what the client specified. + +Authentication +-------------- + +The protocol itself contains no authentication mechanisms. That is to be +handled by the transport, such as SSH, before the 'receive-pack' process is +invoked. If 'receive-pack' is configured over the Git transport, those +repositories will be writable by anyone who can access that port (9418) as +that transport is unauthenticated. + +Reference Discovery +------------------- + +The reference discovery phase is done nearly the same way as it is in the +fetching protocol. Each reference obj-id and name on the server is sent +in packet-line format to the client, followed by a flush-pkt. The only +real difference is that the capability listing is different - the only +possible values are 'report-status', 'delete-refs' and 'ofs-delta'. + +Reference Update Request and Packfile Transfer +---------------------------------------------- + +Once the client knows what references the server is at, it can send a +list of reference update requests. For each reference on the server +that it wants to update, it sends a line listing the obj-id currently on +the server, the obj-id the client would like to update it to and the name +of the reference. + +This list is followed by a flush-pkt and then the packfile that should +contain all the objects that the server will need to complete the new +references. + +---- + update-request = command-list [pack-file] + + command-list = PKT-LINE(command NUL capability-list LF) + *PKT-LINE(command LF) + flush-pkt + + command = create / delete / update + create = zero-id SP new-id SP name + delete = old-id SP zero-id SP name + update = old-id SP new-id SP name + + old-id = obj-id + new-id = obj-id + + pack-file = "PACK" 28*(OCTET) +---- + +If the receiving end does not support delete-refs, the sending end MUST +NOT ask for delete command. + +The pack-file MUST NOT be sent if the only command used is 'delete'. + +A pack-file MUST be sent if either create or update command is used, +even if the server already has all the necessary objects. In this +case the client MUST send an empty pack-file. The only time this +is likely to happen is if the client is creating +a new branch or a tag that points to an existing obj-id. + +The server will receive the packfile, unpack it, then validate each +reference that is being updated that it hasn't changed while the request +was being processed (the obj-id is still the same as the old-id), and +it will run any update hooks to make sure that the update is acceptable. +If all of that is fine, the server will then update the references. + +Report Status +------------- + +After receiving the pack data from the sender, the receiver sends a +report if 'report-status' capability is in effect. +It is a short listing of what happened in that update. It will first +list the status of the packfile unpacking as either 'unpack ok' or +'unpack [error]'. Then it will list the status for each of the references +that it tried to update. Each line is either 'ok [refname]' if the +update was successful, or 'ng [refname] [error]' if the update was not. + +---- + report-status = unpack-status + 1*(command-status) + flush-pkt + + unpack-status = PKT-LINE("unpack" SP unpack-result LF) + unpack-result = "ok" / error-msg + + command-status = command-ok / command-fail + command-ok = PKT-LINE("ok" SP refname LF) + command-fail = PKT-LINE("ng" SP refname SP error-msg LF) + + error-msg = 1*(OCTECT) ; where not "ok" +---- + +Updates can be unsuccessful for a number of reasons. The reference can have +changed since the reference discovery phase was originally sent, meaning +someone pushed in the meantime. The reference being pushed could be a +non-fast-forward reference and the update hooks or configuration could be +set to not allow that, etc. Also, some references can be updated while others +can be rejected. + +An example client/server communication might look like this: + +---- + S: 007c74730d410fcb6603ace96f1dc55ea6196122532d refs/heads/local\0report-status delete-refs ofs-delta\n + S: 003e7d1665144a3a975c05f1f43902ddaf084e784dbe refs/heads/debug\n + S: 003f74730d410fcb6603ace96f1dc55ea6196122532d refs/heads/master\n + S: 003f74730d410fcb6603ace96f1dc55ea6196122532d refs/heads/team\n + S: 0000 + + C: 003e7d1665144a3a975c05f1f43902ddaf084e784dbe 74730d410fcb6603ace96f1dc55ea6196122532d refs/heads/debug\n + C: 003e74730d410fcb6603ace96f1dc55ea6196122532d 5a3f6be755bbb7deae50065988cbfa1ffa9ab68a refs/heads/master\n + C: 0000 + C: [PACKDATA] + + S: 000aunpack ok\n + S: 0014ok refs/heads/debug\n + S: 0026ng refs/heads/master non-fast-forward\n +---- diff --git a/Documentation/technical/protocol-capabilities.txt b/Documentation/technical/protocol-capabilities.txt new file mode 100644 index 0000000000..1892d3eeac --- /dev/null +++ b/Documentation/technical/protocol-capabilities.txt @@ -0,0 +1,187 @@ +Git Protocol Capabilities +========================= + +Servers SHOULD support all capabilities defined in this document. + +On the very first line of the initial server response of either +receive-pack and upload-pack the first reference is followed by +a NUL byte and then a list of space delimited server capabilities. +These allow the server to declare what it can and cannot support +to the client. + +Client will then send a space separated list of capabilities it wants +to be in effect. The client MUST NOT ask for capabilities the server +did not say it supports. + +Server MUST diagnose and abort if capabilities it does not understand +was sent. Server MUST NOT ignore capabilities that client requested +and server advertised. As a consequence of these rules, server MUST +NOT advertise capabilities it does not understand. + +The 'report-status' and 'delete-refs' capabilities are sent and +recognized by the receive-pack (push to server) process. + +The 'ofs-delta' capability is sent and recognized by both upload-pack +and receive-pack protocols. + +All other capabilities are only recognized by the upload-pack (fetch +from server) process. + +multi_ack +--------- + +The 'multi_ack' capability allows the server to return "ACK obj-id +continue" as soon as it finds a commit that it can use as a common +base, between the client's wants and the client's have set. + +By sending this early, the server can potentially head off the client +from walking any further down that particular branch of the client's +repository history. The client may still need to walk down other +branches, sending have lines for those, until the server has a +complete cut across the DAG, or the client has said "done". + +Without multi_ack, a client sends have lines in --date-order until +the server has found a common base. That means the client will send +have lines that are already known by the server to be common, because +they overlap in time with another branch that the server hasn't found +a common base on yet. + +For example suppose the client has commits in caps that the server +doesn't and the server has commits in lower case that the client +doesn't, as in the following diagram: + + +---- u ---------------------- x + / +----- y + / / + a -- b -- c -- d -- E -- F + \ + +--- Q -- R -- S + +If the client wants x,y and starts out by saying have F,S, the server +doesn't know what F,S is. Eventually the client says "have d" and +the server sends "ACK d continue" to let the client know to stop +walking down that line (so don't send c-b-a), but its not done yet, +it needs a base for x. The client keeps going with S-R-Q, until a +gets reached, at which point the server has a clear base and it all +ends. + +Without multi_ack the client would have sent that c-b-a chain anyway, +interleaved with S-R-Q. + +thin-pack +--------- + +This capability means that the server can send a 'thin' pack, a pack +which does not contain base objects; if those base objects are available +on client side. Client requests 'thin-pack' capability when it +understands how to "thicken" it by adding required delta bases making +it self-contained. + +Client MUST NOT request 'thin-pack' capability if it cannot turn a thin +pack into a self-contained pack. + + +side-band, side-band-64k +------------------------ + +This capability means that server can send, and client understand multiplexed +progress reports and error info interleaved with the packfile itself. + +These two options are mutually exclusive. A modern client always +favors 'side-band-64k'. + +Either mode indicates that the packfile data will be streamed broken +up into packets of up to either 1000 bytes in the case of 'side_band', +or 65520 bytes in the case of 'side_band_64k'. Each packet is made up +of a leading 4-byte pkt-line length of how much data is in the packet, +followed by a 1-byte stream code, followed by the actual data. + +The stream code can be one of: + + 1 - pack data + 2 - progress messages + 3 - fatal error message just before stream aborts + +The "side-band-64k" capability came about as a way for newer clients +that can handle much larger packets to request packets that are +actually crammed nearly full, while maintaining backward compatibility +for the older clients. + +Further, with side-band and its up to 1000-byte messages, it's actually +999 bytes of payload and 1 byte for the stream code. With side-band-64k, +same deal, you have up to 65519 bytes of data and 1 byte for the stream +code. + +The client MUST send only maximum of one of "side-band" and "side- +band-64k". Server MUST diagnose it as an error if client requests +both. + +ofs-delta +--------- + +Server can send, and client understand PACKv2 with delta refering to +its base by position in pack rather than by an obj-id. That is, they can +send/read OBJ_OFS_DELTA (aka type 6) in a packfile. + +shallow +------- + +This capability adds "deepen", "shallow" and "unshallow" commands to +the fetch-pack/upload-pack protocol so clients can request shallow +clones. + +no-progress +----------- + +The client was started with "git clone -q" or something, and doesn't +want that side band 2. Basically the client just says "I do not +wish to receive stream 2 on sideband, so do not send it to me, and if +you did, I will drop it on the floor anyway". However, the sideband +channel 3 is still used for error responses. + +include-tag +----------- + +The 'include-tag' capability is about sending annotated tags if we are +sending objects they point to. If we pack an object to the client, and +a tag object points exactly at that object, we pack the tag object too. +In general this allows a client to get all new annotated tags when it +fetches a branch, in a single network connection. + +Clients MAY always send include-tag, hardcoding it into a request when +the server advertises this capability. The decision for a client to +request include-tag only has to do with the client's desires for tag +data, whether or not a server had advertised objects in the +refs/tags/* namespace. + +Servers MUST pack the tags if their referrant is packed and the client +has requested include-tags. + +Clients MUST be prepared for the case where a server has ignored +include-tag and has not actually sent tags in the pack. In such +cases the client SHOULD issue a subsequent fetch to acquire the tags +that include-tag would have otherwise given the client. + +The server SHOULD send include-tag, if it supports it, regardless +of whether or not there are tags available. + +report-status +------------- + +The upload-pack process can receive a 'report-status' capability, +which tells it that the client wants a report of what happened after +a packfile upload and reference update. If the pushing client requests +this capability, after unpacking and updating references the server +will respond with whether the packfile unpacked successfully and if +each reference was updated successfully. If any of those were not +successful, it will send back an error message. See pack-protocol.txt +for example messages. + +delete-refs +----------- + +If the server sends back the 'delete-refs' capability, it means that +it is capable of accepting an zero-id value as the target +value of a reference update. It is not sent back by the client, it +simply informs the client that it can be sent zero-id values +to delete references. diff --git a/Documentation/technical/protocol-common.txt b/Documentation/technical/protocol-common.txt new file mode 100644 index 0000000000..d30a1b9510 --- /dev/null +++ b/Documentation/technical/protocol-common.txt @@ -0,0 +1,96 @@ +Documentation Common to Pack and Http Protocols +=============================================== + +ABNF Notation +------------- + +ABNF notation as described by RFC 5234 is used within the protocol documents, +except the following replacement core rules are used: +---- + HEXDIG = DIGIT / "a" / "b" / "c" / "d" / "e" / "f" +---- + +We also define the following common rules: +---- + NUL = %x00 + zero-id = 40*"0" + obj-id = 40*(HEXDIGIT) + + refname = "HEAD" + refname /= "refs/" <see discussion below> +---- + +A refname is a hierarchical octet string beginning with "refs/" and +not violating the 'git-check-ref-format' command's validation rules. +More specifically, they: + +. They can include slash `/` for hierarchical (directory) + grouping, but no slash-separated component can begin with a + dot `.`. + +. They must contain at least one `/`. This enforces the presence of a + category like `heads/`, `tags/` etc. but the actual names are not + restricted. + +. They cannot have two consecutive dots `..` anywhere. + +. They cannot have ASCII control characters (i.e. bytes whose + values are lower than \040, or \177 `DEL`), space, tilde `~`, + caret `{caret}`, colon `:`, question-mark `?`, asterisk `*`, + or open bracket `[` anywhere. + +. They cannot end with a slash `/` nor a dot `.`. + +. They cannot end with the sequence `.lock`. + +. They cannot contain a sequence `@{`. + +. They cannot contain a `\\`. + + +pkt-line Format +--------------- + +Much (but not all) of the payload is described around pkt-lines. + +A pkt-line is a variable length binary string. The first four bytes +of the line, the pkt-len, indicates the total length of the line, +in hexadecimal. The pkt-len includes the 4 bytes used to contain +the length's hexadecimal representation. + +A pkt-line MAY contain binary data, so implementors MUST ensure +pkt-line parsing/formatting routines are 8-bit clean. + +A non-binary line SHOULD BE terminated by an LF, which if present +MUST be included in the total length. + +The maximum length of a pkt-line's data component is 65520 bytes. +Implementations MUST NOT send pkt-line whose length exceeds 65524 +(65520 bytes of payload + 4 bytes of length data). + +Implementations SHOULD NOT send an empty pkt-line ("0004"). + +A pkt-line with a length field of 0 ("0000"), called a flush-pkt, +is a special case and MUST be handled differently than an empty +pkt-line ("0004"). + +---- + pkt-line = data-pkt / flush-pkt + + data-pkt = pkt-len pkt-payload + pkt-len = 4*(HEXDIG) + pkt-payload = (pkt-len - 4)*(OCTET) + + flush-pkt = "0000" +---- + +Examples (as C-style strings): + +---- + pkt-line actual value + --------------------------------- + "0006a\n" "a\n" + "0005a" "a" + "000bfoobar\n" "foobar\n" + "0004" "" +---- diff --git a/Documentation/user-manual.txt b/Documentation/user-manual.txt index c32dd87c8b..b169836684 100644 --- a/Documentation/user-manual.txt +++ b/Documentation/user-manual.txt @@ -1400,7 +1400,7 @@ were merged. However, if the current branch is a descendant of the other--so every commit present in the one is already contained in the other--then git -just performs a "fast forward"; the head of the current branch is moved +just performs a "fast-forward"; the head of the current branch is moved forward to point at the head of the merged-in branch, without any new commits being created. @@ -1735,7 +1735,7 @@ producing a default commit message documenting the branch and repository that you pulled from. (But note that no such commit will be created in the case of a -<<fast-forwards,fast forward>>; instead, your branch will just be +<<fast-forwards,fast-forward>>; instead, your branch will just be updated to point to the latest commit from the upstream branch.) The `git pull` command can also be given "." as the "remote" repository, @@ -1959,7 +1959,7 @@ $ git push ssh://yourserver.com/~you/proj.git master ------------------------------------------------- As with `git fetch`, `git push` will complain if this does not result in a -<<fast-forwards,fast forward>>; see the following section for details on +<<fast-forwards,fast-forward>>; see the following section for details on handling this case. Note that the target of a "push" is normally a @@ -1992,7 +1992,7 @@ details. What to do when a push fails ~~~~~~~~~~~~~~~~~~~~~~~~~~~~ -If a push would not result in a <<fast-forwards,fast forward>> of the +If a push would not result in a <<fast-forwards,fast-forward>> of the remote branch, then it will fail with an error like: ------------------------------------------------- @@ -2131,7 +2131,7 @@ $ git checkout release && git pull Important note! If you have any local changes in these branches, then this merge will create a commit object in the history (with no local -changes git will simply do a "Fast forward" merge). Many people dislike +changes git will simply do a "fast-forward" merge). Many people dislike the "noise" that this creates in the Linux history, so you should avoid doing this capriciously in the "release" branch, as these noisy commits will become part of the permanent history when you ask Linus to pull @@ -2585,7 +2585,7 @@ them again with linkgit:git-am[1]. Other tools ----------- -There are numerous other tools, such as StGIT, which exist for the +There are numerous other tools, such as StGit, which exist for the purpose of maintaining a patch series. These are outside of the scope of this manual. @@ -2745,9 +2745,9 @@ In the previous example, when updating an existing branch, "git fetch" checks to make sure that the most recent commit on the remote branch is a descendant of the most recent commit on your copy of the branch before updating your copy of the branch to point at the new -commit. Git calls this process a <<fast-forwards,fast forward>>. +commit. Git calls this process a <<fast-forwards,fast-forward>>. -A fast forward looks something like this: +A fast-forward looks something like this: ................................................ o--o--o--o <-- old head of the branch @@ -4291,7 +4291,7 @@ You see, Git is actually the best tool to find out about the source of Git itself! [[glossary]] -GIT Glossary +Git Glossary ============ include::glossary-content.txt[] |