diff options
Diffstat (limited to 'Documentation')
50 files changed, 2026 insertions, 517 deletions
diff --git a/Documentation/.gitignore b/Documentation/.gitignore index 2c8b2d612e..c7096f11f1 100644 --- a/Documentation/.gitignore +++ b/Documentation/.gitignore @@ -11,3 +11,4 @@ doc.dep cmds-*.txt mergetools-*.txt manpage-base-url.xsl +SubmittingPatches.txt diff --git a/Documentation/Makefile b/Documentation/Makefile index 2415e0d657..2ab65561af 100644 --- a/Documentation/Makefile +++ b/Documentation/Makefile @@ -67,6 +67,8 @@ SP_ARTICLES += howto/maintain-git API_DOCS = $(patsubst %.txt,%,$(filter-out technical/api-index-skel.txt technical/api-index.txt, $(wildcard technical/api-*.txt))) SP_ARTICLES += $(API_DOCS) +TECH_DOCS += SubmittingPatches +TECH_DOCS += technical/hash-function-transition TECH_DOCS += technical/http-protocol TECH_DOCS += technical/index-format TECH_DOCS += technical/pack-format @@ -180,6 +182,7 @@ ASCIIDOC = asciidoctor ASCIIDOC_CONF = ASCIIDOC_HTML = xhtml5 ASCIIDOC_DOCBOOK = docbook45 +ASCIIDOC_EXTRA += -acompat-mode ASCIIDOC_EXTRA += -I. -rasciidoctor-extensions ASCIIDOC_EXTRA += -alitdd='&\#x2d;&\#x2d;' DBLATEX_COMMON = @@ -322,6 +325,7 @@ clean: $(RM) *.pdf $(RM) howto-index.txt howto/*.html doc.dep $(RM) technical/*.html technical/api-index.txt + $(RM) SubmittingPatches.txt $(RM) $(cmds_txt) $(mergetools_txt) *.made $(RM) manpage-base-url.xsl @@ -360,6 +364,9 @@ technical/%.html: ASCIIDOC_EXTRA += -a git-relative-html-prefix=../ $(patsubst %,%.html,$(API_DOCS) technical/api-index $(TECH_DOCS)): %.html : %.txt asciidoc.conf $(QUIET_ASCIIDOC)$(TXT_TO_HTML) $*.txt +SubmittingPatches.txt: SubmittingPatches + $(QUIET_GEN) cp $< $@ + XSLT = docbook.xsl XSLTOPTS = --xinclude --stringparam html.stylesheet docbook-xsl.css diff --git a/Documentation/RelNotes/2.15.0.txt b/Documentation/RelNotes/2.15.0.txt new file mode 100644 index 0000000000..cdd761bcc2 --- /dev/null +++ b/Documentation/RelNotes/2.15.0.txt @@ -0,0 +1,508 @@ +Git 2.15 Release Notes +====================== + +Backward compatibility notes and other notable changes. + + * Use of an empty string as a pathspec element that is used for + 'everything matches' is still warned and Git asks users to use a + more explicit '.' for that instead. The hope is that existing + users will not mind this change, and eventually the warning can be + turned into a hard error, upgrading the deprecation into removal of + this (mis)feature. That is now scheduled to happen in Git v2.16, + the next major release after this one. + + * Git now avoids blindly falling back to ".git" when the setup + sequence said we are _not_ in Git repository. A corner case that + happens to work right now may be broken by a call to BUG(). + We've tried hard to locate such cases and fixed them, but there + might still be cases that need to be addressed--bug reports are + greatly appreciated. + + * "branch --set-upstream" that has been deprecated in Git 1.8 has + finally been retired. + + +Updates since v2.14 +------------------- + +UI, Workflows & Features + + * An example that is now obsolete has been removed from a sample hook, + and an old example in it that added a sign-off manually has been + improved to use the interpret-trailers command. + + * The advice message given when "git rebase" stops for conflicting + changes has been improved. + + * The "rerere-train" script (in contrib/) learned the "--overwrite" + option to allow overwriting existing recorded resolutions. + + * "git contacts" (in contrib/) now lists the address on the + "Reported-by:" trailer to its output, in addition to those on + S-o-b: and other trailers, to make it easier to notify (and thank) + the original bug reporter. + + * "git rebase", especially when it is run by mistake and ends up + trying to replay many changes, spent long time in silence. The + command has been taught to show progress report when it spends + long time preparing these many changes to replay (which would give + the user a chance to abort with ^C). + + * "git merge" learned a "--signoff" option to add the Signed-off-by: + trailer with the committer's name. + + * "git diff" learned to optionally paint new lines that are the same + as deleted lines elsewhere differently from genuinely new lines. + + * "git interpret-trailers" learned to take the trailer specifications + from the command line that overrides the configured values. + + * "git interpret-trailers" has been taught a "--parse" and a few + other options to make it easier for scripts to grab existing + trailer lines from a commit log message. + + * The "--format=%(trailers)" option "git log" and its friends take + learned to take the 'unfold' and 'only' modifiers to normalize its + output, e.g. "git log --format=%(trailers:only,unfold)". + + * "gitweb" shows a link to visit the 'raw' contents of blobs in the + history overview page. + + * "[gc] rerereResolved = 5.days" used to be invalid, as the variable + is defined to take an integer counting the number of days. It now + is allowed. + + * The code to acquire a lock on a reference (e.g. while accepting a + push from a client) used to immediately fail when the reference is + already locked---now it waits for a very short while and retries, + which can make it succeed if the lock holder was holding it during + a read-only operation. + + * "branch --set-upstream" that has been deprecated in Git 1.8 has + finally been retired. + + * The codepath to call external process filter for smudge/clean + operation learned to show the progress meter. + + * "git rev-parse" learned "--is-shallow-repository", that is to be + used in a way similar to existing "--is-bare-repository" and + friends. + + * "git describe --match <pattern>" has been taught to play well with + the "--all" option. + + * "git branch" learned "-c/-C" to create a new branch by copying an + existing one. + + * Some commands (most notably "git status") makes an opportunistic + update when performing a read-only operation to help optimize later + operations in the same repository. The new "--no-optional-locks" + option can be passed to Git to disable them. + + * "git for-each-ref --format=..." learned a new format element, + %(trailers), to show only the commit log trailer part of the log + message. + + +Performance, Internal Implementation, Development Support etc. + + * Conversion from uchar[20] to struct object_id continues. + + * Start using selected c99 constructs in small, stable and + essential part of the system to catch people who care about + older compilers that do not grok them. + + * The filter-process interface learned to allow a process with long + latency give a "delayed" response. + + * Many uses of comparison callback function the hashmap API uses + cast the callback function type when registering it to + hashmap_init(), which defeats the compile time type checking when + the callback interface changes (e.g. gaining more parameters). + The callback implementations have been updated to take "void *" + pointers and cast them to the type they expect instead. + + * Because recent Git for Windows do come with a real msgfmt, the + build procedure for git-gui has been updated to use it instead of a + hand-rolled substitute. + + * "git grep --recurse-submodules" has been reworked to give a more + consistent output across submodule boundary (and do its thing + without having to fork a separate process). + + * A helper function to read a single whole line into strbuf + mistakenly triggered OOM error at EOF under certain conditions, + which has been fixed. + + * The "ref-store" code reorganization continues. + + * "git commit" used to discard the index and re-read from the filesystem + just in case the pre-commit hook has updated it in the middle; this + has been optimized out when we know we do not run the pre-commit hook. + (merge 680ee550d7 kw/commit-keep-index-when-pre-commit-is-not-run later to maint). + + * Updates to the HTTP layer we made recently unconditionally used + features of libCurl without checking the existence of them, causing + compilation errors, which has been fixed. Also migrate the code to + check feature macros, not version numbers, to cope better with + libCurl that vendor ships with backported features. + + * The API to start showing progress meter after a short delay has + been simplified. + (merge 8aade107dd jc/simplify-progress later to maint). + + * Code clean-up to avoid mixing values read from the .gitmodules file + and values read from the .git/config file. + + * We used to spend more than necessary cycles allocating and freeing + piece of memory while writing each index entry out. This has been + optimized. + + * Platforms that ship with a separate sha1 with collision detection + library can link to it instead of using the copy we ship as part of + our source tree. + + * Code around "notes" have been cleaned up. + (merge 3964281524 mh/notes-cleanup later to maint). + + * The long-standing rule that an in-core lockfile instance, once it + is used, must not be freed, has been lifted and the lockfile and + tempfile APIs have been updated to reduce the chance of programming + errors. + + * Our hashmap implementation in hashmap.[ch] is not thread-safe when + adding a new item needs to expand the hashtable by rehashing; add + an API to disable the automatic rehashing to work it around. + + * Many of our programs consider that it is OK to release dynamic + storage that is used throughout the life of the program by simply + exiting, but this makes it harder to leak detection tools to avoid + reporting false positives. Plug many existing leaks and introduce + a mechanism for developers to mark that the region of memory + pointed by a pointer is not lost/leaking to help these tools. + + * As "git commit" to conclude a conflicted "git merge" honors the + commit-msg hook, "git merge" that records a merge commit that + cleanly auto-merges should, but it didn't. + + * The codepath for "git merge-recursive" has been cleaned up. + + * Many leaks of strbuf have been fixed. + + * "git imap-send" has our own implementation of the protocol and also + can use more recent libCurl with the imap protocol support. Update + the latter so that it can use the credential subsystem, and then + make it the default option to use, so that we can eventually + deprecate and remove the former. + + * "make style" runs git-clang-format to help developers by pointing + out coding style issues. + + * A test to demonstrate "git mv" failing to adjust nested submodules + has been added. + (merge c514167df2 hv/mv-nested-submodules-test later to maint). + + * On Cygwin, "ulimit -s" does not report failure but it does not work + at all, which causes an unexpected success of some tests that + expect failures under a limited stack situation. This has been + fixed. + + * Many codepaths have been updated to squelch -Wimplicit-fallthrough + warnings from Gcc 7 (which is a good code hygiene). + + * Add a helper for DLL loading in anticipation for its need in a + future topic RSN. + + * "git status --ignored", when noticing that a directory without any + tracked path is ignored, still enumerated all the ignored paths in + the directory, which is unnecessary. The codepath has been + optimized to avoid this overhead. + + * The final batch to "git rebase -i" updates to move more code from + the shell script to C has been merged. + + * Operations that do not touch (majority of) packed refs have been + optimized by making accesses to packed-refs file lazy; we no longer + pre-parse everything, and an access to a single ref in the + packed-refs does not touch majority of irrelevant refs, either. + + * Add comment to clarify that the style file is meant to be used with + clang-5 and the rules are still work in progress. + + * Many variables that points at a region of memory that will live + throughout the life of the program have been marked with UNLEAK + marker to help the leak checkers concentrate on real leaks.. + + * Plans for weaning us off of SHA-1 has been documented. + + * A new "oidmap" API has been introduced and oidset API has been + rewritten to use it. + + +Also contains various documentation updates and code clean-ups. + + +Fixes since v2.14 +----------------- + + * "%C(color name)" in the pretty print format always produced ANSI + color escape codes, which was an early design mistake. They now + honor the configuration (e.g. "color.ui = never") and also tty-ness + of the output medium. + + * The http.{sslkey,sslCert} configuration variables are to be + interpreted as a pathname that honors "~[username]/" prefix, but + weren't, which has been fixed. + + * Numerous bugs in walking of reflogs via "log -g" and friends have + been fixed. + + * "git commit" when seeing an totally empty message said "you did not + edit the message", which is clearly wrong. The message has been + corrected. + + * When a directory is not readable, "gitweb" fails to build the + project list. Work this around by skipping such a directory. + + * Some versions of GnuPG fails to kill gpg-agent it auto-spawned + and such a left-over agent can interfere with a test. Work it + around by attempting to kill one before starting a new test. + + * A recently added test for the "credential-cache" helper revealed + that EOF detection done around the time the connection to the cache + daemon is torn down were flaky. This was fixed by reacting to + ECONNRESET and behaving as if we got an EOF. + + * "git log --tag=no-such-tag" showed log starting from HEAD, which + has been fixed---it now shows nothing. + + * The "tag.pager" configuration variable was useless for those who + actually create tag objects, as it interfered with the use of an + editor. A new mechanism has been introduced for commands to enable + pager depending on what operation is being carried out to fix this, + and then "git tag -l" is made to run pager by default. + + * "git push --recurse-submodules $there HEAD:$target" was not + propagated down to the submodules, but now it is. + + * Commands like "git rebase" accepted the --rerere-autoupdate option + from the command line, but did not always use it. This has been + fixed. + + * "git clone --recurse-submodules --quiet" did not pass the quiet + option down to submodules. + + * Test portability fix for OBSD. + + * Portability fix for OBSD. + + * "git am -s" has been taught that some input may end with a trailer + block that is not Signed-off-by: and it should refrain from adding + an extra blank line before adding a new sign-off in such a case. + + * "git svn" used with "--localtime" option did not compute the tz + offset for the timestamp in question and instead always used the + current time, which has been corrected. + + * Memory leak in an error codepath has been plugged. + + * "git stash -u" used the contents of the committed version of the + ".gitignore" file to decide which paths are ignored, even when the + file has local changes. The command has been taught to instead use + the locally modified contents. + + * bash 4.4 or newer gave a warning on NUL byte in command + substitution done in "git stash"; this has been squelched. + + * "git grep -L" and "git grep --quiet -L" reported different exit + codes; this has been corrected. + + * When handshake with a subprocess filter notices that the process + asked for an unknown capability, Git did not report what program + the offending subprocess was running. This has been corrected. + + * "git apply" that is used as a better "patch -p1" failed to apply a + taken from a file with CRLF line endings to a file with CRLF line + endings. The root cause was because it misused convert_to_git() + that tried to do "safe-crlf" processing by looking at the index + entry at the same path, which is a nonsense---in that mode, "apply" + is not working on the data in (or derived from) the index at all. + This has been fixed. + + * Killing "git merge --edit" before the editor returns control left + the repository in a state with MERGE_MSG but without MERGE_HEAD, + which incorrectly tells the subsequent "git commit" that there was + a squash merge in progress. This has been fixed. + + * "git archive" did not work well with pathspecs and the + export-ignore attribute. + + * In addition to "cc: <a@dd.re.ss> # cruft", "cc: a@dd.re.ss # cruft" + was taught to "git send-email" as a valid way to tell it that it + needs to also send a carbon copy to <a@dd.re.ss> in the trailer + section. + + * "git branch -M a b" while on a branch that is completely unrelated + to either branch a or branch b misbehaved when multiple worktree + was in use. This has been fixed. + (merge 31824d180d nd/worktree-kill-parse-ref later to maint). + + * "git gc" and friends when multiple worktrees are used off of a + single repository did not consider the index and per-worktree refs + of other worktrees as the root for reachability traversal, making + objects that are in use only in other worktrees to be subject to + garbage collection. + + * A regression to "gitk --bisect" by a recent update has been fixed. + + * "git -c submodule.recurse=yes pull" did not work as if the + "--recurse-submodules" option was given from the command line. + This has been corrected. + + * Unlike "git commit-tree < file", "git commit-tree -F file" did not + pass the contents of the file verbatim and instead completed an + incomplete line at the end, if exists. The latter has been updated + to match the behaviour of the former. + + * Many codepaths did not diagnose write failures correctly when disks + go full, due to their misuse of write_in_full() helper function, + which have been corrected. + (merge f48ecd38cb jk/write-in-full-fix later to maint). + + * "git help co" now says "co is aliased to ...", not "git co is". + (merge b3a8076e0d ks/help-alias-label later to maint). + + * "git archive", especially when used with pathspec, stored an empty + directory in its output, even though Git itself never does so. + This has been fixed. + + * API error-proofing which happens to also squelch warnings from GCC. + + * The explanation of the cut-line in the commit log editor has been + slightly tweaked. + (merge 8c4b1a3593 ks/commit-do-not-touch-cut-line later to maint). + + * "git gc" tries to avoid running two instances at the same time by + reading and writing pid/host from and to a lock file; it used to + use an incorrect fscanf() format when reading, which has been + corrected. + + * The scripts to drive TravisCI has been reorganized and then an + optimization to avoid spending cycles on a branch whose tip is + tagged has been implemented. + (merge 8376eb4a8f ls/travis-scriptify later to maint). + + * The test linter has been taught that we do not like "echo -e". + + * Code cmp.std.c nitpick. + + * A regression fix for 2.11 that made the code to read the list of + alternate object stores overrun the end of the string. + (merge f0f7bebef7 jk/info-alternates-fix later to maint). + + * "git describe --match" learned to take multiple patterns in v2.13 + series, but the feature ignored the patterns after the first one + and did not work at all. This has been fixed. + + * "git filter-branch" cannot reproduce a history with a tag without + the tagger field, which only ancient versions of Git allowed to be + created. This has been corrected. + (merge b2c1ca6b4b ic/fix-filter-branch-to-handle-tag-without-tagger later to maint). + + * "git cat-file --textconv" started segfaulting recently, which + has been corrected. + + * The built-in pattern to detect the "function header" for HTML did + not match <H1>..<H6> elements without any attributes, which has + been fixed. + + * "git mailinfo" was loose in decoding quoted printable and produced + garbage when the two letters after the equal sign are not + hexadecimal. This has been fixed. + + * The machinery to create xdelta used in pack files received the + sizes of the data in size_t, but lost the higher bits of them by + storing them in "unsigned int" during the computation, which is + fixed. + + * The delta format used in the packfile cannot reference data at + offset larger than what can be expressed in 4-byte, but the + generator for the data failed to make sure the offset does not + overflow. This has been corrected. + + * The documentation for '-X<option>' for merges was misleadingly + written to suggest that "-s theirs" exists, which is not the case. + + * "git fast-export" with -M/-C option issued "copy" instruction on a + path that is simultaneously modified, which was incorrect. + (merge b3e8ca89cf jt/fast-export-copy-modify-fix later to maint). + + * Many codepaths have been updated to squelch -Wsign-compare + warnings. + (merge 071bcaab64 rj/no-sign-compare later to maint). + + * Memory leaks in various codepaths have been plugged. + (merge 4d01a7fa65 ma/leakplugs later to maint). + + * Recent versions of "git rev-parse --parseopt" did not parse the + option specification that does not have the optional flags (*=?!) + correctly, which has been corrected. + (merge a6304fa4c2 bc/rev-parse-parseopt-fix later to maint). + + * The checkpoint command "git fast-import" did not flush updates to + refs and marks unless at least one object was created since the + last checkpoint, which has been corrected, as these things can + happen without any new object getting created. + (merge 30e215a65c er/fast-import-dump-refs-on-checkpoint later to maint). + + * Spell the name of our system as "Git" in the output from + request-pull script. + + * Fixes for a handful memory access issues identified by valgrind. + + * Backports a moral equivalent of 2015 fix to the poll() emulation + from the upstream gnulib to fix occasional breakages on HPE NonStop. + + * Users with "color.ui = always" in their configuration were broken + by a recent change that made plumbing commands to pay attention to + them as the patch created internally by "git add -p" were colored + (heh) and made unusable. This has been fixed by reverting the + offending change. + + * In the "--format=..." option of the "git for-each-ref" command (and + its friends, i.e. the listing mode of "git branch/tag"), "%(atom:)" + (e.g. "%(refname:)", "%(body:)" used to error out. Instead, treat + them as if the colon and an empty string that follows it were not + there. + + * An ancient bug that made Git misbehave with creation/renaming of + refs has been fixed. + + * "git fetch <there> <src>:<dst>" allows an object name on the <src> + side when the other side accepts such a request since Git v2.5, but + the documentation was left stale. + (merge 83558a412a jc/fetch-refspec-doc-update later to maint). + + * Update the documentation for "git filter-branch" so that the filter + options are listed in the same order as they are applied, as + described in an earlier part of the doc. + (merge 07c4984508 dg/filter-branch-filter-order-doc later to maint). + + * A possible oom error is now caught as a fatal error, instead of + continuing and dereferencing NULL. + (merge 55d7d15847 ao/path-use-xmalloc later to maint). + + * Other minor doc, test and build updates and code cleanups. + (merge f094b89a4d ma/parse-maybe-bool later to maint). + (merge 6cdf8a7929 ma/ts-cleanups later to maint). + (merge 7560f547e6 ma/up-to-date later to maint). + (merge 0db3dc75f3 rs/apply-epoch later to maint). + (merge 276d0e35c0 ma/split-symref-update-fix later to maint). + (merge f777623514 ks/branch-tweak-error-message-for-extra-args later to maint). + (merge 33f3c683ec ks/verify-filename-non-option-error-message-tweak later to maint). + (merge 7cbbf9d6a2 ls/filter-process-delayed later to maint). + (merge 488aa65c8f wk/merge-options-gpg-sign-doc later to maint). + (merge e61cb19a27 jc/branch-force-doc-readability-fix later to maint). + (merge 32fceba3fd np/config-path-doc later to maint). + (merge e38c681fb7 sb/rev-parse-show-superproject-root later to maint). + (merge 4f851dc883 sg/rev-list-doc-reorder-fix later to maint). diff --git a/Documentation/RelNotes/2.15.1.txt b/Documentation/RelNotes/2.15.1.txt new file mode 100644 index 0000000000..ec06704e63 --- /dev/null +++ b/Documentation/RelNotes/2.15.1.txt @@ -0,0 +1,88 @@ +Git v2.15.1 Release Notes +========================= + +Fixes since v2.15 +----------------- + + * TravisCI build updates. + + * "auto" as a value for the columnar output configuration ought to + judge "is the output consumed by humans?" with the same criteria as + "auto" for coloured output configuration, i.e. either the standard + output stream is going to tty, or a pager is in use. We forgot the + latter, which has been fixed. + + * The experimental "color moved lines differently in diff output" + feature was buggy around "ignore whitespace changes" edges, which + has been corrected. + + * Instead of using custom line comparison and hashing functions to + implement "moved lines" coloring in the diff output, use the pair + of these functions from lower-layer xdiff/ code. + + * Some codepaths did not check for errors when asking what branch the + HEAD points at, which have been fixed. + + * "git commit", after making a commit, did not check for errors when + asking on what branch it made the commit, which has been corrected. + + * "git status --ignored -u" did not stop at a working tree of a + separate project that is embedded in an ignored directory and + listed files in that other project, instead of just showing the + directory itself as ignored. + + * A broken access to object databases in recent update to "git grep + --recurse-submodules" has been fixed. + + * A recent regression in "git rebase -i" that broke execution of git + commands from subdirectories via "exec" instruction has been fixed. + + * "git check-ref-format --branch @{-1}" bit a "BUG()" when run + outside a repository for obvious reasons; clarify the documentation + and make sure we do not even try to expand the at-mark magic in + such a case, but still call the validation logic for branch names. + + * Command line completion (in contrib/) update. + + * Description of blame.{showroot,blankboundary,showemail,date} + configuration variables have been added to "git config --help". + + * After an error from lstat(), diff_populate_filespec() function + sometimes still went ahead and used invalid data in struct stat, + which has been fixed. + + * UNC paths are also relevant in Cygwin builds and they are now + tested just like Mingw builds. + + * Correct start-up sequence so that a repository could be placed + immediately under the root directory again (which was broken at + around Git 2.13). + + * The credential helper for libsecret (in contrib/) has been improved + to allow possibly prompting the end user to unlock secrets that are + currently locked (otherwise the secrets may not be loaded). + + * Updates from GfW project. + + * "git rebase -i" recently started misbehaving when a submodule that + is configured with 'submodule.<name>.ignore' is dirty; this has + been corrected. + + * Some error messages did not quote filenames shown in it, which have + been fixed. + + * Building with NO_LIBPCRE1_JIT did not disable it, which has been fixed. + + * We used to add an empty alternate object database to the system + that does not help anything; it has been corrected. + + * Error checking in "git imap-send" for empty response has been + improved. + + * An ancient bug in "git apply --ignore-space-change" codepath has + been fixed. + + * There was a recent semantic mismerge in the codepath to write out a + section of a configuration section, which has been corrected. + +Also contains various documentation updates and code clean-ups. diff --git a/Documentation/RelNotes/2.15.2.txt b/Documentation/RelNotes/2.15.2.txt new file mode 100644 index 0000000000..9f7e28f8a2 --- /dev/null +++ b/Documentation/RelNotes/2.15.2.txt @@ -0,0 +1,47 @@ +Git v2.15.2 Release Notes +========================= + +Fixes since v2.15.1 +------------------- + + * Recent update to the refs infrastructure implementation started + rewriting packed-refs file more often than before; this has been + optimized again for most trivial cases. + + * The SubmittingPatches document has been converted to produce an + HTML version via AsciiDoc/Asciidoctor. + + * Contrary to the documentation, "git pull -4/-6 other-args" did not + ask the underlying "git fetch" to go over IPv4/IPv6, which has been + corrected. + + * When "git rebase" prepared an mailbox of changes and fed it to "git + am" to replay them, it was confused when a stray "From " happened + to be in the log message of one of the replayed changes. This has + been corrected. + + * Command line completion (in contrib/) has been taught about the + "--copy" option of "git branch". + + * "git apply --inaccurate-eof" when used with "--ignore-space-change" + triggered an internal sanity check, which has been fixed. + + * The sequencer machinery (used by "git cherry-pick A..B", and "git + rebase -i", among other things) would have lost a commit if stopped + due to an unlockable index file, which has been fixed. + + * The three-way merge performed by "git cherry-pick" was confused + when a new submodule was added in the meantime, which has been + fixed (or "papered over"). + + * "git notes" sent its error message to its standard output stream, + which was corrected. + + * A few scripts (both in production and tests) incorrectly redirected + their error output. These have been corrected. + + * Clarify and enhance documentation for "merge-base --fork-point", as + it was clear what it computed but not why/what for. + + +Also contains various documentation updates and code clean-ups. diff --git a/Documentation/SubmittingPatches b/Documentation/SubmittingPatches index 558d465b65..3ef30922ec 100644 --- a/Documentation/SubmittingPatches +++ b/Documentation/SubmittingPatches @@ -1,40 +1,47 @@ +Submitting Patches +================== + +== Guidelines + Here are some guidelines for people who want to contribute their code to this software. -(0) Decide what to base your work on. +[[base-branch]] +=== Decide what to base your work on. In general, always base your work on the oldest branch that your change is relevant to. - - A bugfix should be based on 'maint' in general. If the bug is not - present in 'maint', base it on 'master'. For a bug that's not yet - in 'master', find the topic that introduces the regression, and - base your work on the tip of the topic. +* A bugfix should be based on `maint` in general. If the bug is not + present in `maint`, base it on `master`. For a bug that's not yet + in `master`, find the topic that introduces the regression, and + base your work on the tip of the topic. - - A new feature should be based on 'master' in general. If the new - feature depends on a topic that is in 'pu', but not in 'master', - base your work on the tip of that topic. +* A new feature should be based on `master` in general. If the new + feature depends on a topic that is in `pu`, but not in `master`, + base your work on the tip of that topic. - - Corrections and enhancements to a topic not yet in 'master' should - be based on the tip of that topic. If the topic has not been merged - to 'next', it's alright to add a note to squash minor corrections - into the series. +* Corrections and enhancements to a topic not yet in `master` should + be based on the tip of that topic. If the topic has not been merged + to `next`, it's alright to add a note to squash minor corrections + into the series. - - In the exceptional case that a new feature depends on several topics - not in 'master', start working on 'next' or 'pu' privately and send - out patches for discussion. Before the final merge, you may have to - wait until some of the dependent topics graduate to 'master', and - rebase your work. +* In the exceptional case that a new feature depends on several topics + not in `master`, start working on `next` or `pu` privately and send + out patches for discussion. Before the final merge, you may have to + wait until some of the dependent topics graduate to `master`, and + rebase your work. - - Some parts of the system have dedicated maintainers with their own - repositories (see the section "Subsystems" below). Changes to - these parts should be based on their trees. +* Some parts of the system have dedicated maintainers with their own + repositories (see the section "Subsystems" below). Changes to + these parts should be based on their trees. -To find the tip of a topic branch, run "git log --first-parent -master..pu" and look for the merge commit. The second parent of this +To find the tip of a topic branch, run `git log --first-parent +master..pu` and look for the merge commit. The second parent of this commit is the tip of the topic branch. -(1) Make separate commits for logically separate changes. +[[separate-commits]] +=== Make separate commits for logically separate changes. Unless your patch is really trivial, you should not be sending out a patch that was generated between your working tree and @@ -58,8 +65,9 @@ differs substantially from the prior version, are all good things to have. Make sure that you have tests for the bug you are fixing. See -t/README for guidance. +`t/README` for guidance. +[[tests]] When adding a new feature, make sure that you have new tests to show the feature triggers the new behavior when it should, and to show the feature does not trigger when it shouldn't. After any code change, make @@ -84,41 +92,45 @@ turning en_UK spelling to en_US). Obvious typographical fixes are much more welcomed ("teh -> "the"), preferably submitted as independent patches separate from other documentation changes. +[[whitespace-check]] Oh, another thing. We are picky about whitespaces. Make sure your changes do not trigger errors with the sample pre-commit hook shipped -in templates/hooks--pre-commit. To help ensure this does not happen, -run "git diff --check" on your changes before you commit. +in `templates/hooks--pre-commit`. To help ensure this does not happen, +run `git diff --check` on your changes before you commit. - -(2) Describe your changes well. +[[describe-changes]] +=== Describe your changes well. The first line of the commit message should be a short description (50 -characters is the soft limit, see DISCUSSION in git-commit(1)), and -should skip the full stop. It is also conventional in most cases to +characters is the soft limit, see DISCUSSION in linkgit:git-commit[1]), +and should skip the full stop. It is also conventional in most cases to prefix the first line with "area: " where the area is a filename or identifier for the general area of the code being modified, e.g. - . doc: clarify distinction between sign-off and pgp-signing - . githooks.txt: improve the intro section +* doc: clarify distinction between sign-off and pgp-signing +* githooks.txt: improve the intro section -If in doubt which identifier to use, run "git log --no-merges" on the +If in doubt which identifier to use, run `git log --no-merges` on the files you are modifying to see the current conventions. +[[summary-section]] It's customary to start the remainder of the first line after "area: " with a lower-case letter. E.g. "doc: clarify...", not "doc: Clarify...", or "githooks.txt: improve...", not "githooks.txt: Improve...". +[[meaningful-message]] The body should provide a meaningful commit message, which: - . explains the problem the change tries to solve, i.e. what is wrong - with the current code without the change. +. explains the problem the change tries to solve, i.e. what is wrong + with the current code without the change. - . justifies the way the change solves the problem, i.e. why the - result with the change is better. +. justifies the way the change solves the problem, i.e. why the + result with the change is better. - . alternate solutions considered but discarded, if any. +. alternate solutions considered but discarded, if any. +[[imperative-mood]] Describe your changes in imperative mood, e.g. "make xyzzy do frotz" instead of "[This patch] makes xyzzy do frotz" or "[I] changed xyzzy to do frotz", as if you are giving orders to the codebase to change @@ -126,36 +138,43 @@ its behavior. Try to make sure your explanation can be understood without external resources. Instead of giving a URL to a mailing list archive, summarize the relevant points of the discussion. +[[commit-reference]] If you want to reference a previous commit in the history of a stable branch, use the format "abbreviated sha1 (subject, date)", with the subject enclosed in a pair of double-quotes, like this: - Commit f86a374 ("pack-bitmap.c: fix a memleak", 2015-03-30) - noticed that ... +.... + Commit f86a374 ("pack-bitmap.c: fix a memleak", 2015-03-30) + noticed that ... +.... The "Copy commit summary" command of gitk can be used to obtain this -format, or this invocation of "git show": +format, or this invocation of `git show`: - git show -s --date=short --pretty='format:%h ("%s", %ad)' <commit> +.... + git show -s --date=short --pretty='format:%h ("%s", %ad)' <commit> +.... -(3) Generate your patch using Git tools out of your commits. +[[git-tools]] +=== Generate your patch using Git tools out of your commits. Git based diff tools generate unidiff which is the preferred format. -You do not have to be afraid to use -M option to "git diff" or -"git format-patch", if your patch involves file renames. The +You do not have to be afraid to use `-M` option to `git diff` or +`git format-patch`, if your patch involves file renames. The receiving end can handle them just fine. +[[review-patch]] Please make sure your patch does not add commented out debugging code, or include any extra files which do not relate to what your patch is trying to achieve. Make sure to review your patch after generating it, to ensure accuracy. Before -sending out, please make sure it cleanly applies to the "master" +sending out, please make sure it cleanly applies to the `master` branch head. If you are preparing a work based on "next" branch, that is fine, but please mark it as such. - -(4) Sending your patches. +[[send-patches]] +=== Sending your patches. Learn to use format-patch and send-email if possible. These commands are optimized for the workflow of sending patches, avoiding many ways @@ -184,14 +203,15 @@ lose tabs that way if you are not careful. It is a common convention to prefix your subject line with [PATCH]. This lets people easily distinguish patches from other -e-mail discussions. Use of additional markers after PATCH and -the closing bracket to mark the nature of the patch is also -encouraged. E.g. [PATCH/RFC] is often used when the patch is -not ready to be applied but it is for discussion, [PATCH v2], -[PATCH v3] etc. are often seen when you are sending an update to -what you have previously sent. - -"git format-patch" command follows the best current practice to +e-mail discussions. Use of markers in addition to PATCH within +the brackets to describe the nature of the patch is also +encouraged. E.g. [RFC PATCH] (where RFC stands for "request for +comments") is often used to indicate a patch needs further +discussion before being accepted, [PATCH v2], [PATCH v3] etc. +are often seen when you are sending an update to what you have +previously sent. + +The `git format-patch` command follows the best current practice to format the body of an e-mail message. At the beginning of the patch should come your commit message, ending with the Signed-off-by: lines, and a line that consists of three dashes, @@ -199,6 +219,10 @@ followed by the diffstat information and the patch itself. If you are forwarding a patch from somebody else, optionally, at the beginning of the e-mail message just before the commit message starts, you can put a "From: " line to name that person. +To change the default "[PATCH]" in the subject to "[<text>]", use +`git format-patch --subject-prefix=<text>`. As a shortcut, you +can use `--rfc` instead of `--subject-prefix="RFC PATCH"`, or +`-v <n>` instead of `--subject-prefix="PATCH v<n>"`. You often want to add additional explanation about the patch, other than the commit message itself. Place such "cover letter" @@ -208,6 +232,7 @@ an explanation of changes between each iteration can be kept in Git-notes and inserted automatically following the three-dash line via `git format-patch --notes`. +[[attachment]] Do not attach the patch as a MIME attachment, compressed or not. Do not let your e-mail client send quoted-printable. Do not let your e-mail client send format=flowed which would destroy @@ -222,6 +247,7 @@ that it will be postponed. Exception: If your mailer is mangling patches then someone may ask you to re-send them using MIME, that is OK. +[[pgp-signature]] Do not PGP sign your patch. Most likely, your maintainer or other people on the list would not have your PGP key and would not bother obtaining it anyway. Your patch is not judged by who you are; a good patch from an unknown origin @@ -230,28 +256,27 @@ origin that is done poorly or does incorrect things. If you really really really really want to do a PGP signed patch, format it as "multipart/signed", not a text/plain message -that starts with '-----BEGIN PGP SIGNED MESSAGE-----'. That is +that starts with `-----BEGIN PGP SIGNED MESSAGE-----`. That is not a text/plain, it's something else. Send your patch with "To:" set to the mailing list, with "cc:" listing people who are involved in the area you are touching (the output from -"git blame $path" and "git shortlog --no-merges $path" would help to ++git blame _$path_+ and +git shortlog {litdd}no-merges _$path_+ would help to identify them), to solicit comments and reviews. +:1: footnote:[The current maintainer: gitster@pobox.com] +:2: footnote:[The mailing list: git@vger.kernel.org] + After the list reached a consensus that it is a good idea to apply the -patch, re-send it with "To:" set to the maintainer [*1*] and "cc:" the -list [*2*] for inclusion. +patch, re-send it with "To:" set to the maintainer{1} and "cc:" the +list{2} for inclusion. -Do not forget to add trailers such as "Acked-by:", "Reviewed-by:" and -"Tested-by:" lines as necessary to credit people who helped your +Do not forget to add trailers such as `Acked-by:`, `Reviewed-by:` and +`Tested-by:` lines as necessary to credit people who helped your patch. - [Addresses] - *1* The current maintainer: gitster@pobox.com - *2* The mailing list: git@vger.kernel.org - - -(5) Certify your work by adding your "Signed-off-by: " line +[[sign-off]] +=== Certify your work by adding your "Signed-off-by: " line To improve tracking of who did what, we've borrowed the "sign-off" procedure from the Linux kernel project on patches @@ -263,35 +288,39 @@ the patch, which certifies that you wrote it or otherwise have the right to pass it on as a open-source patch. The rules are pretty simple: if you can certify the below D-C-O: - Developer's Certificate of Origin 1.1 - - By making a contribution to this project, I certify that: - - (a) The contribution was created in whole or in part by me and I - have the right to submit it under the open source license - indicated in the file; or - - (b) The contribution is based upon previous work that, to the best - of my knowledge, is covered under an appropriate open source - license and I have the right under that license to submit that - work with modifications, whether created in whole or in part - by me, under the same open source license (unless I am - permitted to submit under a different license), as indicated - in the file; or - - (c) The contribution was provided directly to me by some other - person who certified (a), (b) or (c) and I have not modified - it. - - (d) I understand and agree that this project and the contribution - are public and that a record of the contribution (including all - personal information I submit with it, including my sign-off) is - maintained indefinitely and may be redistributed consistent with - this project or the open source license(s) involved. +[[dco]] +.Developer's Certificate of Origin 1.1 +____ +By making a contribution to this project, I certify that: + +a. The contribution was created in whole or in part by me and I + have the right to submit it under the open source license + indicated in the file; or + +b. The contribution is based upon previous work that, to the best + of my knowledge, is covered under an appropriate open source + license and I have the right under that license to submit that + work with modifications, whether created in whole or in part + by me, under the same open source license (unless I am + permitted to submit under a different license), as indicated + in the file; or + +c. The contribution was provided directly to me by some other + person who certified (a), (b) or (c) and I have not modified + it. + +d. I understand and agree that this project and the contribution + are public and that a record of the contribution (including all + personal information I submit with it, including my sign-off) is + maintained indefinitely and may be redistributed consistent with + this project or the open source license(s) involved. +____ then you just add a line saying - Signed-off-by: Random J Developer <random@developer.example.org> +.... + Signed-off-by: Random J Developer <random@developer.example.org> +.... This line can be automatically added by Git if you run the git-commit command with the -s option. @@ -302,85 +331,86 @@ D-C-O. Indeed you are encouraged to do so. Do not forget to place an in-body "From: " line at the beginning to properly attribute the change to its true author (see (2) above). +[[real-name]] Also notice that a real name is used in the Signed-off-by: line. Please don't hide your real name. +[[commit-trailers]] If you like, you can put extra tags at the end: -1. "Reported-by:" is used to credit someone who found the bug that - the patch attempts to fix. -2. "Acked-by:" says that the person who is more familiar with the area - the patch attempts to modify liked the patch. -3. "Reviewed-by:", unlike the other tags, can only be offered by the - reviewer and means that she is completely satisfied that the patch - is ready for application. It is usually offered only after a - detailed review. -4. "Tested-by:" is used to indicate that the person applied the patch - and found it to have the desired effect. +. `Reported-by:` is used to credit someone who found the bug that + the patch attempts to fix. +. `Acked-by:` says that the person who is more familiar with the area + the patch attempts to modify liked the patch. +. `Reviewed-by:`, unlike the other tags, can only be offered by the + reviewer and means that she is completely satisfied that the patch + is ready for application. It is usually offered only after a + detailed review. +. `Tested-by:` is used to indicate that the person applied the patch + and found it to have the desired effect. You can also create your own tag or use one that's in common usage such as "Thanks-to:", "Based-on-patch-by:", or "Mentored-by:". ------------------------------------------------- -Subsystems with dedicated maintainers +== Subsystems with dedicated maintainers Some parts of the system have dedicated maintainers with their own repositories. - - git-gui/ comes from git-gui project, maintained by Pat Thoyts: +- 'git-gui/' comes from git-gui project, maintained by Pat Thoyts: - git://repo.or.cz/git-gui.git + git://repo.or.cz/git-gui.git - - gitk-git/ comes from Paul Mackerras's gitk project: +- 'gitk-git/' comes from Paul Mackerras's gitk project: - git://ozlabs.org/~paulus/gitk + git://ozlabs.org/~paulus/gitk - - po/ comes from the localization coordinator, Jiang Xin: +- 'po/' comes from the localization coordinator, Jiang Xin: https://github.com/git-l10n/git-po/ Patches to these parts should be based on their trees. ------------------------------------------------- -An ideal patch flow +[[patch-flow]] +== An ideal patch flow Here is an ideal patch flow for this project the current maintainer suggests to the contributors: - (0) You come up with an itch. You code it up. +. You come up with an itch. You code it up. - (1) Send it to the list and cc people who may need to know about - the change. +. Send it to the list and cc people who may need to know about + the change. ++ +The people who may need to know are the ones whose code you +are butchering. These people happen to be the ones who are +most likely to be knowledgeable enough to help you, but +they have no obligation to help you (i.e. you ask for help, +don't demand). +git log -p {litdd} _$area_you_are_modifying_+ would +help you find out who they are. - The people who may need to know are the ones whose code you - are butchering. These people happen to be the ones who are - most likely to be knowledgeable enough to help you, but - they have no obligation to help you (i.e. you ask for help, - don't demand). "git log -p -- $area_you_are_modifying" would - help you find out who they are. +. You get comments and suggestions for improvements. You may + even get them in a "on top of your change" patch form. - (2) You get comments and suggestions for improvements. You may - even get them in a "on top of your change" patch form. +. Polish, refine, and re-send to the list and the people who + spend their time to improve your patch. Go back to step (2). - (3) Polish, refine, and re-send to the list and the people who - spend their time to improve your patch. Go back to step (2). +. The list forms consensus that the last round of your patch is + good. Send it to the maintainer and cc the list. - (4) The list forms consensus that the last round of your patch is - good. Send it to the maintainer and cc the list. - - (5) A topic branch is created with the patch and is merged to 'next', - and cooked further and eventually graduates to 'master'. +. A topic branch is created with the patch and is merged to `next`, + and cooked further and eventually graduates to `master`. In any time between the (2)-(3) cycle, the maintainer may pick it up -from the list and queue it to 'pu', in order to make it easier for +from the list and queue it to `pu`, in order to make it easier for people play with it without having to pick up and apply the patch to their trees themselves. ------------------------------------------------- -Know the status of your patch after submission +[[patch-status]] +== Know the status of your patch after submission * You can use Git itself to find out when your patch is merged in - master. 'git pull --rebase' will automatically skip already-applied + master. `git pull --rebase` will automatically skip already-applied patches, and will let you know. This works only if you rebase on top of the branch in which your patch has been merged (i.e. it will not tell you if your patch is merged in pu if you rebase on top of @@ -390,8 +420,8 @@ Know the status of your patch after submission entitled "What's cooking in git.git" and "What's in git.git" giving the status of various proposed changes. --------------------------------------------------- -GitHub-Travis CI hints +[[travis]] +== GitHub-Travis CI hints With an account at GitHub (you can get one for free to work on open source projects), you can use Travis CI to test your changes on Linux, @@ -400,25 +430,25 @@ test build here: https://travis-ci.org/git/git/builds/120473209 Follow these steps for the initial setup: - (1) Fork https://github.com/git/git to your GitHub account. - You can find detailed instructions how to fork here: - https://help.github.com/articles/fork-a-repo/ +. Fork https://github.com/git/git to your GitHub account. + You can find detailed instructions how to fork here: + https://help.github.com/articles/fork-a-repo/ - (2) Open the Travis CI website: https://travis-ci.org +. Open the Travis CI website: https://travis-ci.org - (3) Press the "Sign in with GitHub" button. +. Press the "Sign in with GitHub" button. - (4) Grant Travis CI permissions to access your GitHub account. - You can find more information about the required permissions here: - https://docs.travis-ci.com/user/github-oauth-scopes +. Grant Travis CI permissions to access your GitHub account. + You can find more information about the required permissions here: + https://docs.travis-ci.com/user/github-oauth-scopes - (5) Open your Travis CI profile page: https://travis-ci.org/profile +. Open your Travis CI profile page: https://travis-ci.org/profile - (6) Enable Travis CI builds for your Git fork. +. Enable Travis CI builds for your Git fork. After the initial setup, Travis CI will run whenever you push new changes to your fork of Git on GitHub. You can monitor the test state of all your -branches here: https://travis-ci.org/<Your GitHub handle>/git/branches +branches here: https://travis-ci.org/__<Your GitHub handle>__/git/branches If a branch did not pass all test cases then it is marked with a red cross. In that case you can click on the failing Travis CI job and @@ -430,17 +460,16 @@ example: https://travis-ci.org/git/git/jobs/122676187 Fix the problem and push your fix to your Git fork. This will trigger a new Travis CI build to ensure all tests pass. - ------------------------------------------------- -MUA specific hints +[[mua]] +== MUA specific hints Some of patches I receive or pick up from the list share common patterns of breakage. Please make sure your MUA is set up properly not to corrupt whitespaces. -See the DISCUSSION section of git-format-patch(1) for hints on +See the DISCUSSION section of linkgit:git-format-patch[1] for hints on checking your patch by mailing it to yourself and applying with -git-am(1). +linkgit:git-am[1]. While you are at it, check the resulting commit log message from a trial run of applying the patch. If what is in the resulting @@ -452,23 +481,24 @@ should come after the three-dash line that signals the end of the commit message. -Pine ----- +=== Pine (Johannes Schindelin) +.... I don't know how many people still use pine, but for those poor souls it may be good to mention that the quell-flowed-text is needed for recent versions. ... the "no-strip-whitespace-before-send" option, too. AFAIK it was introduced in 4.60. +.... (Linus Torvalds) +.... And 4.58 needs at least this. ---- diff-tree 8326dd8350be64ac7fc805f6563a1d61ad10d32c (from e886a61f76edf5410573e92e38ce22974f9c40f1) Author: Linus Torvalds <torvalds@g5.osdl.org> Date: Mon Aug 15 17:23:51 2005 -0700 @@ -490,10 +520,11 @@ diff --git a/pico/pico.c b/pico/pico.c +#endif c |= COMP_EXIT; break; - +.... (Daniel Barkalow) +.... > A patch to SubmittingPatches, MUA specific help section for > users of Pine 4.63 would be very much appreciated. @@ -503,23 +534,21 @@ that or Gentoo did it.) So you need to set the "no-strip-whitespace-before-send" option, unless the option you have is "strip-whitespace-before-send", in which case you should avoid checking it. +.... +=== Thunderbird, KMail, GMail -Thunderbird, KMail, GMail -------------------------- - -See the MUA-SPECIFIC HINTS section of git-format-patch(1). +See the MUA-SPECIFIC HINTS section of linkgit:git-format-patch[1]. -Gnus ----- +=== Gnus -'|' in the *Summary* buffer can be used to pipe the current +"|" in the `*Summary*` buffer can be used to pipe the current message to an external program, and this is a handy way to drive -"git am". However, if the message is MIME encoded, what is +`git am`. However, if the message is MIME encoded, what is piped into the program is the representation you see in your -*Article* buffer after unwrapping MIME. This is often not what +`*Article*` buffer after unwrapping MIME. This is often not what you would want for two reasons. It tends to screw up non ASCII characters (most notably in people's names), and also -whitespaces (fatal in patches). Running 'C-u g' to display the -message in raw form before using '|' to run the pipe can work +whitespaces (fatal in patches). Running "C-u g" to display the +message in raw form before using "|" to run the pipe can work this problem around. diff --git a/Documentation/config.txt b/Documentation/config.txt index 2271809d90..9593bfabaa 100644 --- a/Documentation/config.txt +++ b/Documentation/config.txt @@ -776,6 +776,12 @@ core.commentChar:: If set to "auto", `git-commit` would select a character that is not the beginning character of any line in existing commit messages. +core.filesRefLockTimeout:: + The length of time, in milliseconds, to retry when trying to + lock an individual reference. Value 0 means not to retry at + all; -1 means to try indefinitely. Default is 100 (i.e., + retry for 100ms). + core.packedRefsTimeout:: The length of time, in milliseconds, to retry when trying to lock the `packed-refs` file. Value 0 means not to retry at @@ -943,6 +949,23 @@ apply.whitespace:: Tells 'git apply' how to handle whitespaces, in the same way as the `--whitespace` option. See linkgit:git-apply[1]. +blame.showRoot:: + Do not treat root commits as boundaries in linkgit:git-blame[1]. + This option defaults to false. + +blame.blankBoundary:: + Show blank commit object name for boundary commits in + linkgit:git-blame[1]. This option defaults to false. + +blame.showEmail:: + Show the author email instead of author name in linkgit:git-blame[1]. + This option defaults to false. + +blame.date:: + Specifies the format used to output dates in linkgit:git-blame[1]. + If unset the iso format is used. For supported values, + see the discussion of the `--date` option at linkgit:git-log[1]. + branch.autoSetupMerge:: Tells 'git branch' and 'git checkout' to set up new branches so that linkgit:git-pull[1] will appropriately merge from the @@ -1077,14 +1100,25 @@ This does not affect linkgit:git-format-patch[1] or the 'git-diff-{asterisk}' plumbing commands. Can be overridden on the command line with the `--color[=<when>]` option. +diff.colorMoved:: + If set to either a valid `<mode>` or a true value, moved lines + in a diff are colored differently, for details of valid modes + see '--color-moved' in linkgit:git-diff[1]. If simply set to + true the default color mode will be used. When set to false, + moved lines are not colored. + 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 `context` (context text - `plain` is a historical synonym), `meta` (metainformation), `frag` (hunk header), 'func' (function in hunk header), `old` (removed lines), - `new` (added lines), `commit` (commit headers), or `whitespace` - (highlighting whitespace errors). + `new` (added lines), `commit` (commit headers), `whitespace` + (highlighting whitespace errors), `oldMoved` (deleted lines), + `newMoved` (added lines), `oldMovedDimmed`, `oldMovedAlternative`, + `oldMovedAlternativeDimmed`, `newMovedDimmed`, `newMovedAlternative` + and `newMovedAlternativeDimmed` (See the '<mode>' + setting of '--color-moved' in linkgit:git-diff[1] for details). color.decorate.<slot>:: Use customized color for 'git log --decorate' output. `<slot>` is one @@ -1553,11 +1587,13 @@ gc.<pattern>.reflogExpireUnreachable:: gc.rerereResolved:: Records of conflicted merge you resolved earlier are kept for this many days when 'git rerere gc' is run. + You can also use more human-readable "1.month.ago", etc. The default is 60 days. See linkgit:git-rerere[1]. gc.rerereUnresolved:: Records of conflicted merge you have not resolved are kept for this many days when 'git rerere gc' is run. + You can also use more human-readable "1.month.ago", etc. The default is 15 days. See linkgit:git-rerere[1]. gitcvs.commitMsgAnnotation:: @@ -3066,10 +3102,14 @@ submodule.<name>.url:: See linkgit:git-submodule[1] and linkgit:gitmodules[5] for details. submodule.<name>.update:: - The default update procedure for a submodule. This variable - is populated by `git submodule init` from the - linkgit:gitmodules[5] file. See description of 'update' - command in linkgit:git-submodule[1]. + The method by which a submodule is updated by 'git submodule update', + which is the only affected command, others such as + 'git checkout --recurse-submodules' are unaffected. It exists for + historical reasons, when 'git submodule' was the only command to + interact with submodules; settings like `submodule.active` + and `pull.rebase` are more specific. It is populated by + `git submodule init` from the linkgit:gitmodules[5] file. + See description of 'update' command in linkgit:git-submodule[1]. submodule.<name>.branch:: The remote branch name for a submodule, used by `git submodule diff --git a/Documentation/diff-heuristic-options.txt b/Documentation/diff-heuristic-options.txt deleted file mode 100644 index d4f3d95505..0000000000 --- a/Documentation/diff-heuristic-options.txt +++ /dev/null @@ -1,5 +0,0 @@ ---indent-heuristic:: ---no-indent-heuristic:: - These are to help debugging and tuning experimental heuristics - (which are off by default) that shift diff hunk boundaries to - make patches easier to read. diff --git a/Documentation/diff-options.txt b/Documentation/diff-options.txt index 56dedafcd4..dd0dba5b1d 100644 --- a/Documentation/diff-options.txt +++ b/Documentation/diff-options.txt @@ -63,7 +63,12 @@ ifndef::git-format-patch[] Synonym for `-p --raw`. endif::git-format-patch[] -include::diff-heuristic-options.txt[] +--indent-heuristic:: + Enable the heuristic that shift diff hunk boundaries to make patches + easier to read. This is the default. + +--no-indent-heuristic:: + Disable the indent heuristic. --minimal:: Spend extra time to make sure the smallest possible @@ -231,6 +236,40 @@ ifdef::git-diff[] endif::git-diff[] It is the same as `--color=never`. +--color-moved[=<mode>]:: + Moved lines of code are colored differently. +ifdef::git-diff[] + It can be changed by the `diff.colorMoved` configuration setting. +endif::git-diff[] + The <mode> defaults to 'no' if the option is not given + and to 'zebra' if the option with no mode is given. + The mode must be one of: ++ +-- +no:: + Moved lines are not highlighted. +default:: + Is a synonym for `zebra`. This may change to a more sensible mode + in the future. +plain:: + Any line that is added in one location and was removed + in another location will be colored with 'color.diff.newMoved'. + Similarly 'color.diff.oldMoved' will be used for removed lines + that are added somewhere else in the diff. This mode picks up any + moved line, but it is not very useful in a review to determine + if a block of code was moved without permutation. +zebra:: + Blocks of moved text of at least 20 alphanumeric characters + are detected greedily. The detected blocks are + painted using either the 'color.diff.{old,new}Moved' color or + 'color.diff.{old,new}MovedAlternative'. The change between + the two colors indicates that a new block was detected. +dimmed_zebra:: + Similar to 'zebra', but additional dimming of uninteresting parts + of moved code is performed. The bordering lines of two adjacent + blocks are considered interesting, the rest is uninteresting. +-- + --word-diff[=<mode>]:: Show a word diff, using the <mode> to delimit changed words. By default, words are delimited by whitespace; see diff --git a/Documentation/git-annotate.txt b/Documentation/git-annotate.txt index 94be4b85e0..05fd482b74 100644 --- a/Documentation/git-annotate.txt +++ b/Documentation/git-annotate.txt @@ -23,7 +23,6 @@ familiar command name for people coming from other SCM systems. OPTIONS ------- include::blame-options.txt[] -include::diff-heuristic-options.txt[] SEE ALSO -------- diff --git a/Documentation/git-apply.txt b/Documentation/git-apply.txt index 631cbd840a..4ebc3d3271 100644 --- a/Documentation/git-apply.txt +++ b/Documentation/git-apply.txt @@ -66,7 +66,7 @@ OPTIONS 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 working tree is not - up-to-date, it is flagged as an error. This flag also + up to date, it is flagged as an error. This flag also causes the index file to be updated. --cached:: @@ -259,7 +259,7 @@ treats these changes as follows. 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 +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 diff --git a/Documentation/git-blame.txt b/Documentation/git-blame.txt index fdc3aea30a..16323eb80e 100644 --- a/Documentation/git-blame.txt +++ b/Documentation/git-blame.txt @@ -89,8 +89,6 @@ include::blame-options.txt[] abbreviated object name, use <n>+1 digits. Note that 1 column is used for a caret to mark the boundary commit. -include::diff-heuristic-options.txt[] - THE PORCELAIN FORMAT -------------------- diff --git a/Documentation/git-branch.txt b/Documentation/git-branch.txt index 7463dc44a7..d6587c5e96 100644 --- a/Documentation/git-branch.txt +++ b/Documentation/git-branch.txt @@ -18,6 +18,7 @@ SYNOPSIS 'git branch' (--set-upstream-to=<upstream> | -u <upstream>) [<branchname>] 'git branch' --unset-upstream [<branchname>] 'git branch' (-m | -M) [<oldbranch>] <newbranch> +'git branch' (-c | -C) [<oldbranch>] <newbranch> 'git branch' (-d | -D) [-r] <branchname>... 'git branch' --edit-description [<branchname>] @@ -64,6 +65,10 @@ If <oldbranch> had a corresponding reflog, it is renamed to match renaming. If <newbranch> exists, -M must be used to force the rename to happen. +The `-c` and `-C` options have the exact same semantics as `-m` and +`-M`, except instead of the branch being renamed it along with its +config and reflog will be copied to a new name. + With a `-d` or `-D` option, `<branchname>` will be deleted. You may specify more than one branch for deletion. If the branch currently has a reflog then the reflog will also be deleted. @@ -99,12 +104,12 @@ OPTIONS -f:: --force:: - Reset <branchname> to <startpoint> if <branchname> exists - already. Without `-f` 'git branch' refuses to change an existing branch. + Reset <branchname> to <startpoint>, even if <branchname> exists + already. Without `-f`, 'git branch' refuses to change an existing branch. In combination with `-d` (or `--delete`), allow deleting the branch irrespective of its merged status. In combination with `-m` (or `--move`), allow renaming the branch even if the new - branch name already exists. + branch name already exists, the same applies for `-c` (or `--copy`). -m:: --move:: @@ -113,6 +118,13 @@ OPTIONS -M:: Shortcut for `--move --force`. +-c:: +--copy:: + Copy a branch and the corresponding reflog. + +-C:: + Shortcut for `--copy --force`. + --color[=<when>]:: Color branches to highlight current, local, and remote-tracking branches. @@ -195,10 +207,8 @@ start-point is either a local or remote-tracking branch. branch.autoSetupMerge configuration variable is true. --set-upstream:: - If specified branch does not exist yet or if `--force` has been - given, acts exactly like `--track`. Otherwise sets up configuration - like `--track` would when creating the branch, except that where - branch points to is not changed. + As this option had confusing syntax, it is no longer supported. + Please use `--track` or `--set-upstream-to` instead. -u <upstream>:: --set-upstream-to=<upstream>:: diff --git a/Documentation/git-check-ref-format.txt b/Documentation/git-check-ref-format.txt index 92777cef25..cf0a0b7df2 100644 --- a/Documentation/git-check-ref-format.txt +++ b/Documentation/git-check-ref-format.txt @@ -77,7 +77,14 @@ reference name expressions (see linkgit:gitrevisions[7]): . at-open-brace `@{` is used as a notation to access a reflog entry. -With the `--branch` option, it expands the ``previous branch syntax'' +With the `--branch` option, the command takes a name and checks if +it can be used as a valid branch name (e.g. when creating a new +branch). The rule `git check-ref-format --branch $name` implements +may be stricter than what `git check-ref-format refs/heads/$name` +says (e.g. a dash may appear at the beginning of a ref component, +but it is explicitly forbidden at the beginning of a branch name). +When run with `--branch` option in a repository, the input is first +expanded for 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 diff --git a/Documentation/git-config.txt b/Documentation/git-config.txt index 83f86b9231..4edd09fc6b 100644 --- a/Documentation/git-config.txt +++ b/Documentation/git-config.txt @@ -174,11 +174,11 @@ See also <<FILES>>. either --bool or --int, as described above. --path:: - 'git-config' will expand leading '{tilde}' to the value of - '$HOME', and '{tilde}user' to the home directory for the + `git config` will expand a leading `~` to the value of + `$HOME`, and `~user` to the home directory for the specified user. This option has no effect when setting the - value (but you can use 'git config bla {tilde}/' from the - command line to let your shell do the expansion). + value (but you can use `git config section.variable ~/` + from the command line to let your shell do the expansion). -z:: --null:: diff --git a/Documentation/git-cvsserver.txt b/Documentation/git-cvsserver.txt index a336ae5f6f..ba90066f10 100644 --- a/Documentation/git-cvsserver.txt +++ b/Documentation/git-cvsserver.txt @@ -223,7 +223,7 @@ access method and requested operation. That means that even if you offer only read access (e.g. by using the pserver method), 'git-cvsserver' should have write access to the database to work reliably (otherwise you need to make sure -that the database is up-to-date any time 'git-cvsserver' is executed). +that the database is up to date any time 'git-cvsserver' is executed). By default it uses SQLite databases in the Git directory, named `gitcvs.<module_name>.sqlite`. Note that the SQLite backend creates diff --git a/Documentation/git-describe.txt b/Documentation/git-describe.txt index 26f19d3b07..c924c945ba 100644 --- a/Documentation/git-describe.txt +++ b/Documentation/git-describe.txt @@ -87,19 +87,23 @@ OPTIONS --match <pattern>:: Only consider tags matching the given `glob(7)` pattern, - excluding the "refs/tags/" prefix. This can be used to avoid - leaking private tags from the repository. If given multiple times, a - list of patterns will be accumulated, and tags matching any of the - patterns will be considered. Use `--no-match` to clear and reset the - list of patterns. + excluding the "refs/tags/" prefix. If used with `--all`, it also + considers local branches and remote-tracking references matching the + pattern, excluding respectively "refs/heads/" and "refs/remotes/" + prefix; references of other types are never considered. If given + multiple times, a list of patterns will be accumulated, and tags + matching any of the patterns will be considered. Use `--no-match` to + clear and reset the list of patterns. --exclude <pattern>:: Do not consider tags matching the given `glob(7)` pattern, excluding - the "refs/tags/" prefix. This can be used to narrow the tag space and - find only tags matching some meaningful criteria. If given multiple - times, a list of patterns will be accumulated and tags matching any - of the patterns will be excluded. When combined with --match a tag will - be considered when it matches at least one --match pattern and does not + the "refs/tags/" prefix. If used with `--all`, it also does not consider + local branches and remote-tracking references matching the pattern, + excluding respectively "refs/heads/" and "refs/remotes/" prefix; + references of other types are never considered. If given multiple times, + a list of patterns will be accumulated and tags matching any of the + patterns will be excluded. When combined with --match a tag will be + considered when it matches at least one --match pattern and does not match any of the --exclude patterns. Use `--no-exclude` to clear and reset the list of patterns. diff --git a/Documentation/git-diff-index.txt b/Documentation/git-diff-index.txt index a171506952..b380677718 100644 --- a/Documentation/git-diff-index.txt +++ b/Documentation/git-diff-index.txt @@ -85,7 +85,7 @@ a 'git write-tree' + 'git diff-tree'. Thus that's the default mode. The non-cached version asks the question: show me the differences between HEAD and the currently checked out - tree - index contents _and_ files that aren't up-to-date + tree - index contents _and_ files that aren't up to date which is obviously a very useful question too, since that tells you what you *could* commit. Again, the output matches the 'git diff-tree -r' @@ -100,8 +100,8 @@ have not actually done a 'git update-index' on it yet - there is no torvalds@ppc970:~/v2.6/linux> git diff-index --abbrev HEAD :100644 100664 7476bb... 000000... kernel/sched.c -i.e., it shows that the tree has changed, and that `kernel/sched.c` has is -not up-to-date and may contain new stuff. The all-zero sha1 means that to +i.e., it shows that the tree has changed, and that `kernel/sched.c` is +not up to date and may contain new stuff. The all-zero sha1 means that to get the real diff, you need to look at the object in the working directory directly rather than do an object-to-object diff. diff --git a/Documentation/git-filter-branch.txt b/Documentation/git-filter-branch.txt index 9e5169aa64..3a52e4dce3 100644 --- a/Documentation/git-filter-branch.txt +++ b/Documentation/git-filter-branch.txt @@ -8,13 +8,13 @@ git-filter-branch - Rewrite branches SYNOPSIS -------- [verse] -'git filter-branch' [--setup <command>] [--env-filter <command>] - [--tree-filter <command>] [--index-filter <command>] - [--parent-filter <command>] [--msg-filter <command>] - [--commit-filter <command>] [--tag-name-filter <command>] - [--subdirectory-filter <directory>] [--prune-empty] +'git filter-branch' [--setup <command>] [--subdirectory-filter <directory>] + [--env-filter <command>] [--tree-filter <command>] + [--index-filter <command>] [--parent-filter <command>] + [--msg-filter <command>] [--commit-filter <command>] + [--tag-name-filter <command>] [--prune-empty] [--original <namespace>] [-d <directory>] [-f | --force] - [--] [<rev-list options>...] + [--state-branch <branch>] [--] [<rev-list options>...] DESCRIPTION ----------- @@ -89,6 +89,11 @@ OPTIONS can be used or modified in the following filter steps except the commit filter, for technical reasons. +--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. Implies <<Remap_to_ancestor>>. + --env-filter <command>:: This filter may be used if you only need to modify the environment in which the commit will be performed. Specifically, you might @@ -167,11 +172,6 @@ be removed, buyer beware. There is also no support for changing the author or timestamp (or the tag message for that matter). Tags which point 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. Implies <<Remap_to_ancestor>>. - --prune-empty:: Some filters will generate empty commits that leave the tree untouched. This option instructs git-filter-branch to remove such commits if they @@ -198,6 +198,12 @@ to other tags will be rewritten to point to the underlying commit. directory or when there are already refs starting with 'refs/original/', unless forced. +--state-branch <branch>:: + This option will cause the mapping from old to new objects to + be loaded from named branch upon startup and saved as a new + commit to that branch upon exit, enabling incremental of large + trees. If '<branch>' does not exist it will be created. + <rev-list options>...:: Arguments for 'git rev-list'. All positive refs included by these options are rewritten. You may also specify options diff --git a/Documentation/git-for-each-ref.txt b/Documentation/git-for-each-ref.txt index cbd0a6212a..1d420e4cde 100644 --- a/Documentation/git-for-each-ref.txt +++ b/Documentation/git-for-each-ref.txt @@ -218,11 +218,15 @@ and `date` to extract the named component. The complete message in a commit and tag object is `contents`. Its first line is `contents:subject`, where subject is the concatenation of all lines of the commit message up to the first blank line. The next -line is 'contents:body', where body is all of the lines after the first +line is `contents:body`, where body is all of the lines after the first blank line. The optional GPG signature is `contents:signature`. The first `N` lines of the message is obtained using `contents:lines=N`. Additionally, the trailers as interpreted by linkgit:git-interpret-trailers[1] -are obtained as 'contents:trailers'. +are obtained as `trailers` (or by using the historical alias +`contents:trailers`). Non-trailer lines from the trailer block can be omitted +with `trailers:only`. Whitespace-continuations can be removed from trailers so +that each trailer appears on a line by itself with its full content with +`trailers:unfold`. Both can be used together as `trailers:unfold,only`. For sorting purposes, fields with numeric values sort in numeric order (`objectsize`, `authordate`, `committerdate`, `creatordate`, `taggerdate`). diff --git a/Documentation/git-format-patch.txt b/Documentation/git-format-patch.txt index c890328b02..6cbe462a77 100644 --- a/Documentation/git-format-patch.txt +++ b/Documentation/git-format-patch.txt @@ -23,6 +23,7 @@ SYNOPSIS [(--reroll-count|-v) <n>] [--to=<email>] [--cc=<email>] [--[no-]cover-letter] [--quiet] [--notes[=<ref>]] + [--progress] [<common diff options>] [ <since> | <revision range> ] @@ -283,6 +284,9 @@ you can use `--suffix=-patch` to get `0001-description-of-my-change-patch`. range are always formatted as creation patches, independently of this flag. +--progress:: + Show progress reports on stderr as patches are generated. + CONFIGURATION ------------- You can specify extra mail header lines to be added to each message, diff --git a/Documentation/git-grep.txt b/Documentation/git-grep.txt index 5edb1da46f..18b494731f 100644 --- a/Documentation/git-grep.txt +++ b/Documentation/git-grep.txt @@ -95,13 +95,6 @@ OPTIONS <tree> option the prefix of all submodule output will be the name of the parent project's <tree> object. ---parent-basename <basename>:: - For internal use only. In order to produce uniform output with the - --recurse-submodules option, this option can be used to provide the - basename of a parent's <tree> object to a submodule so the submodule - can prefix its output with the parent's name rather than the SHA1 of - the submodule. - -a:: --text:: Process binary files as if they were text. diff --git a/Documentation/git-interpret-trailers.txt b/Documentation/git-interpret-trailers.txt index 31cdeaecdf..9dd19a1dd9 100644 --- a/Documentation/git-interpret-trailers.txt +++ b/Documentation/git-interpret-trailers.txt @@ -3,24 +3,27 @@ git-interpret-trailers(1) NAME ---- -git-interpret-trailers - help add structured information into commit messages +git-interpret-trailers - add or parse structured information in commit messages SYNOPSIS -------- [verse] -'git interpret-trailers' [--in-place] [--trim-empty] [(--trailer <token>[(=|:)<value>])...] [<file>...] +'git interpret-trailers' [options] [(--trailer <token>[(=|:)<value>])...] [<file>...] +'git interpret-trailers' [options] [--parse] [<file>...] DESCRIPTION ----------- -Help adding 'trailers' lines, that look similar to RFC 822 e-mail +Help parsing or adding 'trailers' lines, that look similar to RFC 822 e-mail headers, at the end of the otherwise free-form part of a commit message. This command reads some patches or commit messages from either the -<file> arguments or the standard input if no <file> is specified. Then -this command applies the arguments passed using the `--trailer` -option, if any, to the commit message part of each input file. The -result is emitted on the standard output. +<file> arguments or the standard input if no <file> is specified. If +`--parse` is specified, the output consists of the parsed trailers. + +Otherwise, this command applies the arguments passed using the +`--trailer` option, if any, to the commit message part of each input +file. The result is emitted on the standard output. Some configuration variables control the way the `--trailer` arguments are applied to each commit message and the way any existing trailer in @@ -80,6 +83,45 @@ OPTIONS trailer to the input messages. See the description of this command. +--where <placement>:: +--no-where:: + Specify where all new trailers will be added. A setting + provided with '--where' overrides all configuration variables + and applies to all '--trailer' options until the next occurrence of + '--where' or '--no-where'. + +--if-exists <action>:: +--no-if-exists:: + Specify what action will be performed when there is already at + least one trailer with the same <token> in the message. A setting + provided with '--if-exists' overrides all configuration variables + and applies to all '--trailer' options until the next occurrence of + '--if-exists' or '--no-if-exists'. + +--if-missing <action>:: +--no-if-missing:: + Specify what action will be performed when there is no other + trailer with the same <token> in the message. A setting + provided with '--if-missing' overrides all configuration variables + and applies to all '--trailer' options until the next occurrence of + '--if-missing' or '--no-if-missing'. + +--only-trailers:: + Output only the trailers, not any other parts of the input. + +--only-input:: + Output only trailers that exist in the input; do not add any + from the command-line or by following configured `trailer.*` + rules. + +--unfold:: + Remove any whitespace-continuation in trailers, so that each + trailer appears on a line by itself with its full content. + +--parse:: + A convenience alias for `--only-trailers --only-input + --unfold`. + CONFIGURATION VARIABLES ----------------------- @@ -170,8 +212,8 @@ trailer.<token>.where:: configuration variable and it overrides what is specified by that option for trailers with the specified <token>. -trailer.<token>.ifexist:: - This option takes the same values as the 'trailer.ifexist' +trailer.<token>.ifexists:: + This option takes the same values as the 'trailer.ifexists' configuration variable and it overrides what is specified by that option for trailers with the specified <token>. diff --git a/Documentation/git-merge-base.txt b/Documentation/git-merge-base.txt index b968b64c38..502e00ec35 100644 --- a/Documentation/git-merge-base.txt +++ b/Documentation/git-merge-base.txt @@ -154,23 +154,71 @@ topic origin/master`, the history of remote-tracking branch `origin/master` may have been rewound and rebuilt, leading to a history of this shape: - o---B1 + o---B2 / - ---o---o---B2--o---o---o---B (origin/master) + ---o---o---B1--o---o---o---B (origin/master) \ - B3 + B0 \ - Derived (topic) + D0---D1---D (topic) -where `origin/master` used to point at commits B3, B2, B1 and now it +where `origin/master` used to point at commits B0, B1, B2 and now it points at B, and your `topic` branch was started on top of it back -when `origin/master` was at B3. This mode uses the reflog of -`origin/master` to find B3 as the fork point, so that the `topic` -can be rebased on top of the updated `origin/master` by: +when `origin/master` was at B0, and you built three commits, D0, D1, +and D, on top of it. Imagine that you now want to rebase the work +you did on the topic on top of the updated origin/master. + +In such a case, `git merge-base origin/master topic` would return the +parent of B0 in the above picture, but B0^..D is *not* the range of +commits you would want to replay on top of B (it includes B0, which +is not what you wrote; it is a commit the other side discarded when +it moved its tip from B0 to B1). + +`git merge-base --fork-point origin/master topic` is designed to +help in such a case. It takes not only B but also B0, B1, and B2 +(i.e. old tips of the remote-tracking branches your repository's +reflog knows about) into account to see on which commit your topic +branch was built and finds B0, allowing you to replay only the +commits on your topic, excluding the commits the other side later +discarded. + +Hence $ fork_point=$(git merge-base --fork-point origin/master topic) + +will find B0, and + $ git rebase --onto origin/master $fork_point topic +will replay D0, D1 and D on top of B to create a new history of this +shape: + + o---B2 + / + ---o---o---B1--o---o---o---B (origin/master) + \ \ + B0 D0'--D1'--D' (topic - updated) + \ + D0---D1---D (topic - old) + +A caveat is that older reflog entries in your repository may be +expired by `git gc`. If B0 no longer appears in the reflog of the +remote-tracking branch `origin/master`, the `--fork-point` mode +obviously cannot find it and fails, avoiding to give a random and +useless result (such as the parent of B0, like the same command +without the `--fork-point` option gives). + +Also, the remote-tracking branch you use the `--fork-point` mode +with must be the one your topic forked from its tip. If you forked +from an older commit than the tip, this mode would not find the fork +point (imagine in the above sample history B0 did not exist, +origin/master started at B1, moved to B2 and then B, and you forked +your topic at origin/master^ when origin/master was B1; the shape of +the history would be the same as above, without B0, and the parent +of B1 is what `git merge-base origin/master topic` correctly finds, +but the `--fork-point` mode will not, because it is not one of the +commits that used to be at the tip of origin/master). + See also -------- diff --git a/Documentation/git-merge.txt b/Documentation/git-merge.txt index f90faf7aaa..3c6927b1fb 100644 --- a/Documentation/git-merge.txt +++ b/Documentation/git-merge.txt @@ -64,11 +64,13 @@ OPTIONS ------- include::merge-options.txt[] --S[<keyid>]:: ---gpg-sign[=<keyid>]:: - GPG-sign the resulting merge commit. The `keyid` argument is - optional and defaults to the committer identity; if specified, - it must be stuck to the option without a space. +--signoff:: + Add Signed-off-by line by the committer at the end of the commit + log message. The meaning of a signoff depends on the project, + but it typically certifies that committer has + the rights to submit this work under the same license and + agrees to a Developer Certificate of Origin + (see http://developercertificate.org/ for more information). -m <msg>:: Set the commit message to be used for the merge commit (in @@ -133,7 +135,7 @@ exception is when the changed index entries are in the state that would result from the merge already.) If all named commits are already ancestors of `HEAD`, 'git merge' -will exit early with the message "Already up-to-date." +will exit early with the message "Already up to date." FAST-FORWARD MERGE ------------------ diff --git a/Documentation/git-push.txt b/Documentation/git-push.txt index 0a639664fd..3e76e99f38 100644 --- a/Documentation/git-push.txt +++ b/Documentation/git-push.txt @@ -12,7 +12,7 @@ SYNOPSIS 'git push' [--all | --mirror | --tags] [--follow-tags] [--atomic] [-n | --dry-run] [--receive-pack=<git-receive-pack>] [--repo=<repository>] [-f | --force] [-d | --delete] [--prune] [-v | --verbose] [-u | --set-upstream] [--push-option=<string>] - [--[no-]signed|--sign=(true|false|if-asked)] + [--[no-]signed|--signed=(true|false|if-asked)] [--force-with-lease[=<refname>[:<expect>]]] [--no-verify] [<repository> [<refspec>...]] @@ -141,7 +141,7 @@ already exists on the remote side. information, see `push.followTags` in linkgit:git-config[1]. --[no-]signed:: ---sign=(true|false|if-asked):: +--signed=(true|false|if-asked):: GPG-sign the push request to update refs on the receiving side, to allow it to be checked by the hooks and/or be logged. If `false` or `--no-signed`, no signing will be diff --git a/Documentation/git-rebase.txt b/Documentation/git-rebase.txt index 4f6bed61a9..3cedfb0fd2 100644 --- a/Documentation/git-rebase.txt +++ b/Documentation/git-rebase.txt @@ -334,7 +334,7 @@ which makes little sense. -f:: --force-rebase:: - Force a rebase even if the current branch is up-to-date and + Force a rebase even if the current branch is up to date and the command without `--force` would return without doing anything. + You may find this (or --no-ff with an interactive rebase) helpful after @@ -430,13 +430,15 @@ without an explicit `--interactive`. --autosquash:: --no-autosquash:: When the commit log message begins with "squash! ..." (or - "fixup! ..."), and there is a commit whose title begins with - the same ..., automatically modify the todo list of rebase -i - so that the commit marked for squashing comes right after the - commit to be modified, and change the action of the moved - commit from `pick` to `squash` (or `fixup`). Ignores subsequent - "fixup! " or "squash! " after the first, in case you referred to an - earlier fixup/squash with `git commit --fixup/--squash`. + "fixup! ..."), and there is already a commit in the todo list that + matches the same `...`, automatically modify the todo list of rebase + -i so that the commit marked for squashing comes right after the + commit to be modified, and change the action of the moved commit + from `pick` to `squash` (or `fixup`). A commit matches the `...` if + the commit subject matches, or if the `...` refers to the commit's + hash. As a fall-back, partial matches of the commit subject work, + too. The recommended way to create fixup/squash commits is by using + the `--fixup`/`--squash` options of linkgit:git-commit[1]. + This option is only valid when the `--interactive` option is used. + diff --git a/Documentation/git-rerere.txt b/Documentation/git-rerere.txt index 9ee083c415..031f31fa47 100644 --- a/Documentation/git-rerere.txt +++ b/Documentation/git-rerere.txt @@ -205,7 +205,7 @@ development on the topic branch: ------------ you could run `git rebase master topic`, to bring yourself -up-to-date before your topic is ready to be sent upstream. +up to date before your topic is ready to be sent upstream. This would result in falling back to a three-way merge, and it would conflict the same way as the test merge you resolved earlier. 'git rerere' will be run by 'git rebase' to help you resolve this diff --git a/Documentation/git-rev-parse.txt b/Documentation/git-rev-parse.txt index b1293f24bb..95326b85ff 100644 --- a/Documentation/git-rev-parse.txt +++ b/Documentation/git-rev-parse.txt @@ -235,6 +235,9 @@ print a message to stderr and exit with nonzero status. --is-bare-repository:: When the repository is bare print "true", otherwise "false". +--is-shallow-repository:: + When the repository is shallow print "true", otherwise "false". + --resolve-git-dir <path>:: Check if <path> is a valid repository or a gitfile that points at a valid repository, and print the location of the @@ -261,7 +264,7 @@ print a message to stderr and exit with nonzero status. --show-toplevel:: Show the absolute path of the top-level directory. ---show-superproject-working-tree +--show-superproject-working-tree:: Show the absolute path of the root of the superproject's working tree (if exists) that uses the current repository as its submodule. Outputs nothing if the current repository is diff --git a/Documentation/git-rm.txt b/Documentation/git-rm.txt index 683e591330..b5c46223c4 100644 --- a/Documentation/git-rm.txt +++ b/Documentation/git-rm.txt @@ -146,7 +146,7 @@ the submodule's history. If it exists the submodule.<name> section in the linkgit:gitmodules[5] file will also be removed and that file will be staged (unless --cached or -n are used). -A submodule is considered up-to-date when the HEAD is the same as +A submodule is considered up to date when the HEAD is the same as recorded in the index, no tracked files are modified and no untracked files that aren't ignored are present in the submodules work tree. Ignored files are deemed expendable and won't stop a submodule's work diff --git a/Documentation/git-send-pack.txt b/Documentation/git-send-pack.txt index 966abb0df8..f51c64939b 100644 --- a/Documentation/git-send-pack.txt +++ b/Documentation/git-send-pack.txt @@ -11,7 +11,7 @@ SYNOPSIS [verse] 'git send-pack' [--all] [--dry-run] [--force] [--receive-pack=<git-receive-pack>] [--verbose] [--thin] [--atomic] - [--[no-]signed|--sign=(true|false|if-asked)] + [--[no-]signed|--signed=(true|false|if-asked)] [<host>:]<directory> [<ref>...] DESCRIPTION @@ -71,7 +71,7 @@ be in a separate packet, and the list must end with a flush packet. refs. --[no-]signed:: ---sign=(true|false|if-asked):: +--signed=(true|false|if-asked):: GPG-sign the push request to update refs on the receiving side, to allow it to be checked by the hooks and/or be logged. If `false` or `--no-signed`, no signing will be diff --git a/Documentation/git-svn.txt b/Documentation/git-svn.txt index aa2aeabb60..636e09048e 100644 --- a/Documentation/git-svn.txt +++ b/Documentation/git-svn.txt @@ -424,7 +424,7 @@ Any other arguments are passed directly to 'git log' 'set-tree':: You should consider using 'dcommit' instead of this command. Commit specified commit or tree objects to SVN. This relies on - your imported fetch data being up-to-date. This makes + your imported fetch data being up to date. This makes absolutely no attempts to do patching when committing to SVN, it simply overwrites files with those specified in the tree or commit. All merging is assumed to have taken place diff --git a/Documentation/git-update-index.txt b/Documentation/git-update-index.txt index a14e6aebd9..75c7dd9dea 100644 --- a/Documentation/git-update-index.txt +++ b/Documentation/git-update-index.txt @@ -214,7 +214,7 @@ will remove the intended effect of the option. Using --refresh --------------- `--refresh` does not calculate a new sha1 file or bring the index -up-to-date for mode/content changes. But what it *does* do is to +up to date for mode/content changes. But what it *does* do is to "re-match" the stat information of a file with the index, so that you can refresh the index for a file that hasn't been changed but where the stat entry is out of date. diff --git a/Documentation/git.txt b/Documentation/git.txt index 98b9b46b9e..463b0eb0f5 100644 --- a/Documentation/git.txt +++ b/Documentation/git.txt @@ -159,6 +159,10 @@ foo.bar= ...`) sets `foo.bar` to the empty string which `git config Add "icase" magic to all pathspec. This is equivalent to setting the `GIT_ICASE_PATHSPECS` environment variable to `1`. +--no-optional-locks:: + Do not perform optional operations that require locks. This is + equivalent to setting the `GIT_OPTIONAL_LOCKS` to `0`. + GIT COMMANDS ------------ @@ -697,6 +701,32 @@ of clones and fetches. which feed potentially-untrusted URLS to git commands. See linkgit:git-config[1] for more details. +`GIT_OPTIONAL_LOCKS`:: + If set to `0`, Git will complete any requested operation without + performing any optional sub-operations that require taking a lock. + For example, this will prevent `git status` from refreshing the + index as a side effect. This is useful for processes running in + the background which do not want to cause lock contention with + other operations on the repository. Defaults to `1`. + +`GIT_REDIRECT_STDIN`:: +`GIT_REDIRECT_STDOUT`:: +`GIT_REDIRECT_STDERR`:: + Windows-only: allow redirecting the standard input/output/error + handles to paths specified by the environment variables. This is + particularly useful in multi-threaded applications where the + canonical way to pass standard handles via `CreateProcess()` is + not an option because it would require the handles to be marked + inheritable (and consequently *every* spawned process would + inherit them, possibly blocking regular Git operations). The + primary intended use case is to use named pipes for communication + (e.g. `\\.\pipe\my-git-stdin-123`). ++ +Two special values are supported: `off` will simply close the +corresponding standard handle, and if `GIT_REDIRECT_STDERR` is +`2>&1`, standard error will be redirected to the same handle as +standard output. + Discussion[[Discussion]] ------------------------ diff --git a/Documentation/gitcore-tutorial.txt b/Documentation/gitcore-tutorial.txt index 7577f27ec2..e29a9effcc 100644 --- a/Documentation/gitcore-tutorial.txt +++ b/Documentation/gitcore-tutorial.txt @@ -631,7 +631,7 @@ So after you do a `cp -a` to create a new copy, you'll want to do $ git update-index --refresh ---------------- + -in the new repository to make sure that the index file is up-to-date. +in the new repository to make sure that the index file is up to date. Note that the second point is true even across machines. You can duplicate a remote Git repository with *any* regular copy mechanism, be it @@ -701,7 +701,7 @@ $ git checkout-index -u -a ---------------- where the `-u` flag means that you want the checkout to keep the index -up-to-date (so that you don't have to refresh it afterward), and the +up to date (so that you don't have to refresh it afterward), and the `-a` flag means "check out all files" (if you have a stale copy or an older version of a checked out tree you may also need to add the `-f` flag first, to tell 'git checkout-index' to *force* overwriting of any old @@ -1283,7 +1283,7 @@ run a single command, 'git-receive-pack'. First, you need to create an empty repository on the remote machine that will house your public repository. This empty -repository will be populated and be kept up-to-date by pushing +repository will be populated and be kept up to date by pushing into it later. Obviously, this repository creation needs to be done only once. @@ -1450,7 +1450,7 @@ transport protocols (HTTP), you need to keep this repository would contain a call to 'git update-server-info' but you need to manually enable the hook with `mv post-update.sample post-update`. This makes sure -'git update-server-info' keeps the necessary files up-to-date. +'git update-server-info' keeps the necessary files up to date. 3. Push into the public repository from your primary repository. diff --git a/Documentation/githooks.txt b/Documentation/githooks.txt index b2514f4d44..5d3f45560e 100644 --- a/Documentation/githooks.txt +++ b/Documentation/githooks.txt @@ -121,17 +121,16 @@ it is not suppressed by the `--no-verify` option. A non-zero exit means a failure of the hook and aborts the commit. It should not be used as replacement for pre-commit hook. -The sample `prepare-commit-msg` hook that comes with Git comments -out the `Conflicts:` part of a merge's commit message. +The sample `prepare-commit-msg` hook that comes with Git removes the +help message found in the commented portion of the commit template. commit-msg ~~~~~~~~~~ -This hook is invoked by 'git commit', and can be bypassed -with the `--no-verify` option. It takes a single parameter, the -name of the file that holds the proposed commit log message. -Exiting with a non-zero status causes the 'git commit' to -abort. +This hook is invoked by 'git commit' and 'git merge', and can be +bypassed with the `--no-verify` option. It takes a single parameter, +the name of the file that holds the proposed commit log message. +Exiting with a non-zero status causes the command to abort. The hook is allowed to edit the message file in place, and can be used to normalize the message into some project standard format. It @@ -369,7 +368,7 @@ them. When enabled, the default 'post-update' hook runs 'git update-server-info' to keep the information used by dumb -transports (e.g., HTTP) up-to-date. If you are publishing +transports (e.g., HTTP) up to date. If you are publishing a Git repository that is accessible via HTTP, you should probably enable this hook. diff --git a/Documentation/gitrepository-layout.txt b/Documentation/gitrepository-layout.txt index f51ed4e37c..adf9554ad2 100644 --- a/Documentation/gitrepository-layout.txt +++ b/Documentation/gitrepository-layout.txt @@ -71,7 +71,7 @@ objects/info/packs:: This file is to help dumb transports discover what packs are available in this object store. Whenever a pack is added or removed, `git update-server-info` should be run - to keep this file up-to-date if the repository is + to keep this file up to date if the repository is published for dumb transports. 'git repack' does this by default. diff --git a/Documentation/gittutorial.txt b/Documentation/gittutorial.txt index 794b83393e..242de31cb6 100644 --- a/Documentation/gittutorial.txt +++ b/Documentation/gittutorial.txt @@ -109,7 +109,7 @@ summary of the situation with 'git status': $ git status On branch master Changes to be committed: -Your branch is up-to-date with 'origin/master'. +Your branch is up to date with 'origin/master'. (use "git reset HEAD <file>..." to unstage) modified: file1 diff --git a/Documentation/merge-options.txt b/Documentation/merge-options.txt index 5b4a62e936..2552ab8e8d 100644 --- a/Documentation/merge-options.txt +++ b/Documentation/merge-options.txt @@ -39,9 +39,15 @@ set to `no` at the beginning of them. --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 + current `HEAD` is already up to date or the merge can be resolved as a fast-forward. +-S[<keyid>]:: +--gpg-sign[=<keyid>]:: + GPG-sign the resulting merge commit. The `keyid` argument is + optional and defaults to the committer identity; if specified, + it must be stuck to the option without a space. + --log[=<n>]:: --no-log:: In addition to branch names, populate the log message with diff --git a/Documentation/pretty-formats.txt b/Documentation/pretty-formats.txt index 973d19606b..d433d50f81 100644 --- a/Documentation/pretty-formats.txt +++ b/Documentation/pretty-formats.txt @@ -205,7 +205,10 @@ endif::git-rev-list[] - '%><(<N>)', '%><|(<N>)': similar to '% <(<N>)', '%<|(<N>)' respectively, but padding both sides (i.e. the text is centered) - %(trailers): display the trailers of the body as interpreted by - linkgit:git-interpret-trailers[1] + linkgit:git-interpret-trailers[1]. If the `:only` option is given, + omit non-trailer lines from the trailer block. If the `:unfold` + option is given, behave as if interpret-trailer's `--unfold` option + was given. E.g., `%(trailers:only:unfold)` to do both. NOTE: Some placeholders may depend on other options given to the revision traversal engine. For example, the `%g*` reflog options will diff --git a/Documentation/rev-list-options.txt b/Documentation/rev-list-options.txt index a6cf9eb380..13501e1556 100644 --- a/Documentation/rev-list-options.txt +++ b/Documentation/rev-list-options.txt @@ -184,6 +184,14 @@ explicitly. Pretend as if all objects mentioned by reflogs are listed on the command line as `<commit>`. +--single-worktree:: + By default, all working trees will be examined by the + following options when there are more than one (see + linkgit:git-worktree[1]): `--all`, `--reflog` and + `--indexed-objects`. + This option forces them to examine the current working tree + only. + --ignore-missing:: Upon seeing an invalid object name in the input, pretend as if the bad input was not given. @@ -791,11 +799,11 @@ endif::git-rev-list[] --parents:: Print also the parents of the commit (in the form "commit parent..."). - Also enables parent rewriting, see 'History Simplification' below. + Also enables parent rewriting, see 'History Simplification' above. --children:: Print also the children of the commit (in the form "commit child..."). - Also enables parent rewriting, see 'History Simplification' below. + Also enables parent rewriting, see 'History Simplification' above. ifdef::git-rev-list[] --timestamp:: @@ -838,7 +846,7 @@ you would get an output like this: to be drawn properly. Cannot be combined with `--no-walk`. + -This enables parent rewriting, see 'History Simplification' below. +This enables parent rewriting, see 'History Simplification' above. + This implies the `--topo-order` option by default, but the `--date-order` option may also be specified. diff --git a/Documentation/technical/api-argv-array.txt b/Documentation/technical/api-argv-array.txt index cfc063018c..870c8edbfb 100644 --- a/Documentation/technical/api-argv-array.txt +++ b/Documentation/technical/api-argv-array.txt @@ -8,7 +8,7 @@ always NULL-terminated at the element pointed to by `argv[argc]`. This makes the result suitable for passing to functions expecting to receive argv from main(), or the link:api-run-command.html[run-command API]. -The link:api-string-list.html[string-list API] is similar, but cannot be +The string-list API (documented in string-list.h) is similar, but cannot be used for these purposes; instead of storing a straight string pointer, it contains an item structure with a `util` field that is not compatible with the traditional argv interface. diff --git a/Documentation/technical/api-config.txt b/Documentation/technical/api-config.txt index 20741f345e..9a778b0cad 100644 --- a/Documentation/technical/api-config.txt +++ b/Documentation/technical/api-config.txt @@ -186,7 +186,7 @@ parsing is successful, the return value is the result. Same as `git_config_bool`, except that integers are returned as-is, and an `is_bool` flag is unset. -`git_config_maybe_bool`:: +`git_parse_maybe_bool`:: Same as `git_config_bool`, except that it returns -1 on error rather than dying. diff --git a/Documentation/technical/api-ref-iteration.txt b/Documentation/technical/api-ref-iteration.txt index 37379d8337..46c3d5c355 100644 --- a/Documentation/technical/api-ref-iteration.txt +++ b/Documentation/technical/api-ref-iteration.txt @@ -32,11 +32,8 @@ Iteration functions * `for_each_glob_ref_in()` the previous and `for_each_ref_in()` combined. -* `head_ref_submodule()`, `for_each_ref_submodule()`, - `for_each_ref_in_submodule()`, `for_each_tag_ref_submodule()`, - `for_each_branch_ref_submodule()`, `for_each_remote_ref_submodule()` - do the same as the functions described above but for a specified - submodule. +* Use `refs_` API for accessing submodules. The submodule ref store could + be obtained with `get_submodule_ref_store()`. * `for_each_rawref()` can be used to learn about broken ref and symref. diff --git a/Documentation/technical/api-string-list.txt b/Documentation/technical/api-string-list.txt deleted file mode 100644 index c08402b12e..0000000000 --- a/Documentation/technical/api-string-list.txt +++ /dev/null @@ -1,209 +0,0 @@ -string-list API -=============== - -The string_list API offers a data structure and functions to handle -sorted and unsorted string lists. A "sorted" list is one whose -entries are sorted by string value in `strcmp()` order. - -The 'string_list' struct used to be called 'path_list', but was renamed -because it is not specific to paths. - -The caller: - -. Allocates and clears a `struct string_list` variable. - -. Initializes the members. You might want to set the flag `strdup_strings` - if the strings should be strdup()ed. For example, this is necessary - when you add something like git_path("..."), since that function returns - a static buffer that will change with the next call to git_path(). -+ -If you need something advanced, you can manually malloc() the `items` -member (you need this if you add things later) and you should set the -`nr` and `alloc` members in that case, too. - -. Adds new items to the list, using `string_list_append`, - `string_list_append_nodup`, `string_list_insert`, - `string_list_split`, and/or `string_list_split_in_place`. - -. Can check if a string is in the list using `string_list_has_string` or - `unsorted_string_list_has_string` and get it from the list using - `string_list_lookup` for sorted lists. - -. Can sort an unsorted list using `string_list_sort`. - -. Can remove duplicate items from a sorted list using - `string_list_remove_duplicates`. - -. Can remove individual items of an unsorted list using - `unsorted_string_list_delete_item`. - -. Can remove items not matching a criterion from a sorted or unsorted - list using `filter_string_list`, or remove empty strings using - `string_list_remove_empty_items`. - -. Finally it should free the list using `string_list_clear`. - -Example: - ----- -struct string_list list = STRING_LIST_INIT_NODUP; -int i; - -string_list_append(&list, "foo"); -string_list_append(&list, "bar"); -for (i = 0; i < list.nr; i++) - printf("%s\n", list.items[i].string) ----- - -NOTE: It is more efficient to build an unsorted list and sort it -afterwards, instead of building a sorted list (`O(n log n)` instead of -`O(n^2)`). -+ -However, if you use the list to check if a certain string was added -already, you should not do that (using unsorted_string_list_has_string()), -because the complexity would be quadratic again (but with a worse factor). - -Functions ---------- - -* General ones (works with sorted and unsorted lists as well) - -`string_list_init`:: - - Initialize the members of the string_list, set `strdup_strings` - member according to the value of the second parameter. - -`filter_string_list`:: - - Apply a function to each item in a list, retaining only the - items for which the function returns true. If free_util is - true, call free() on the util members of any items that have - to be deleted. Preserve the order of the items that are - retained. - -`string_list_remove_empty_items`:: - - Remove any empty strings from the list. If free_util is true, - call free() on the util members of any items that have to be - deleted. Preserve the order of the items that are retained. - -`print_string_list`:: - - Dump a string_list to stdout, useful mainly for debugging purposes. It - can take an optional header argument and it writes out the - string-pointer pairs of the string_list, each one in its own line. - -`string_list_clear`:: - - Free a string_list. The `string` pointer of the items will be freed in - case the `strdup_strings` member of the string_list is set. The second - parameter controls if the `util` pointer of the items should be freed - or not. - -* Functions for sorted lists only - -`string_list_has_string`:: - - Determine if the string_list has a given string or not. - -`string_list_insert`:: - - Insert a new element to the string_list. The returned pointer can be - handy if you want to write something to the `util` pointer of the - string_list_item containing the just added string. If the given - string already exists the insertion will be skipped and the - pointer to the existing item returned. -+ -Since this function uses xrealloc() (which die()s if it fails) if the -list needs to grow, it is safe not to check the pointer. I.e. you may -write `string_list_insert(...)->util = ...;`. - -`string_list_lookup`:: - - Look up a given string in the string_list, returning the containing - string_list_item. If the string is not found, NULL is returned. - -`string_list_remove_duplicates`:: - - Remove all but the first of consecutive entries that have the - same string value. If free_util is true, call free() on the - util members of any items that have to be deleted. - -* Functions for unsorted lists only - -`string_list_append`:: - - Append a new string to the end of the string_list. If - `strdup_string` is set, then the string argument is copied; - otherwise the new `string_list_entry` refers to the input - string. - -`string_list_append_nodup`:: - - Append a new string to the end of the string_list. The new - `string_list_entry` always refers to the input string, even if - `strdup_string` is set. This function can be used to hand - ownership of a malloc()ed string to a `string_list` that has - `strdup_string` set. - -`string_list_sort`:: - - Sort the list's entries by string value in `strcmp()` order. - -`unsorted_string_list_has_string`:: - - It's like `string_list_has_string()` but for unsorted lists. - -`unsorted_string_list_lookup`:: - - It's like `string_list_lookup()` but for unsorted lists. -+ -The above two functions need to look through all items, as opposed to their -counterpart for sorted lists, which performs a binary search. - -`unsorted_string_list_delete_item`:: - - Remove an item from a string_list. The `string` pointer of the items - will be freed in case the `strdup_strings` member of the string_list - is set. The third parameter controls if the `util` pointer of the - items should be freed or not. - -`string_list_split`:: -`string_list_split_in_place`:: - - Split a string into substrings on a delimiter character and - append the substrings to a `string_list`. If `maxsplit` is - non-negative, then split at most `maxsplit` times. Return the - number of substrings appended to the list. -+ -`string_list_split` requires a `string_list` that has `strdup_strings` -set to true; it leaves the input string untouched and makes copies of -the substrings in newly-allocated memory. -`string_list_split_in_place` requires a `string_list` that has -`strdup_strings` set to false; it splits the input string in place, -overwriting the delimiter characters with NULs and creating new -string_list_items that point into the original string (the original -string must therefore not be modified or freed while the `string_list` -is in use). - - -Data structures ---------------- - -* `struct string_list_item` - -Represents an item of the list. The `string` member is a pointer to the -string, and you may use the `util` member for any purpose, if you want. - -* `struct string_list` - -Represents the list itself. - -. The array of items are available via the `items` member. -. The `nr` member contains the number of items stored in the list. -. The `alloc` member is used to avoid reallocating at every insertion. - You should not tamper with it. -. Setting the `strdup_strings` member to 1 will strdup() the strings - before adding them, see above. -. The `compare_strings_fn` member is used to specify a custom compare - function, otherwise `strcmp()` is used as the default function. diff --git a/Documentation/technical/api-tree-walking.txt b/Documentation/technical/api-tree-walking.txt index 14af37c3f1..bde18622a8 100644 --- a/Documentation/technical/api-tree-walking.txt +++ b/Documentation/technical/api-tree-walking.txt @@ -55,9 +55,9 @@ Initializing `fill_tree_descriptor`:: - Initialize a `tree_desc` and decode its first entry given the sha1 of - a tree. Returns the `buffer` member if the sha1 is a valid tree - identifier and NULL otherwise. + Initialize a `tree_desc` and decode its first entry given the + object ID of a tree. Returns the `buffer` member if the latter + is a valid tree identifier and NULL otherwise. `setup_traverse_info`:: diff --git a/Documentation/technical/hash-function-transition.txt b/Documentation/technical/hash-function-transition.txt new file mode 100644 index 0000000000..417ba491d0 --- /dev/null +++ b/Documentation/technical/hash-function-transition.txt @@ -0,0 +1,797 @@ +Git hash function transition +============================ + +Objective +--------- +Migrate Git from SHA-1 to a stronger hash function. + +Background +---------- +At its core, the Git version control system is a content addressable +filesystem. It uses the SHA-1 hash function to name content. For +example, files, directories, and revisions are referred to by hash +values unlike in other traditional version control systems where files +or versions are referred to via sequential numbers. The use of a hash +function to address its content delivers a few advantages: + +* Integrity checking is easy. Bit flips, for example, are easily + detected, as the hash of corrupted content does not match its name. +* Lookup of objects is fast. + +Using a cryptographically secure hash function brings additional +advantages: + +* Object names can be signed and third parties can trust the hash to + address the signed object and all objects it references. +* Communication using Git protocol and out of band communication + methods have a short reliable string that can be used to reliably + address stored content. + +Over time some flaws in SHA-1 have been discovered by security +researchers. https://shattered.io demonstrated a practical SHA-1 hash +collision. As a result, SHA-1 cannot be considered cryptographically +secure any more. This impacts the communication of hash values because +we cannot trust that a given hash value represents the known good +version of content that the speaker intended. + +SHA-1 still possesses the other properties such as fast object lookup +and safe error checking, but other hash functions are equally suitable +that are believed to be cryptographically secure. + +Goals +----- +Where NewHash is a strong 256-bit hash function to replace SHA-1 (see +"Selection of a New Hash", below): + +1. The transition to NewHash can be done one local repository at a time. + a. Requiring no action by any other party. + b. A NewHash repository can communicate with SHA-1 Git servers + (push/fetch). + c. Users can use SHA-1 and NewHash identifiers for objects + interchangeably (see "Object names on the command line", below). + d. New signed objects make use of a stronger hash function than + SHA-1 for their security guarantees. +2. Allow a complete transition away from SHA-1. + a. Local metadata for SHA-1 compatibility can be removed from a + repository if compatibility with SHA-1 is no longer needed. +3. Maintainability throughout the process. + a. The object format is kept simple and consistent. + b. Creation of a generalized repository conversion tool. + +Non-Goals +--------- +1. Add NewHash support to Git protocol. This is valuable and the + logical next step but it is out of scope for this initial design. +2. Transparently improving the security of existing SHA-1 signed + objects. +3. Intermixing objects using multiple hash functions in a single + repository. +4. Taking the opportunity to fix other bugs in Git's formats and + protocols. +5. Shallow clones and fetches into a NewHash repository. (This will + change when we add NewHash support to Git protocol.) +6. Skip fetching some submodules of a project into a NewHash + repository. (This also depends on NewHash support in Git + protocol.) + +Overview +-------- +We introduce a new repository format extension. Repositories with this +extension enabled use NewHash instead of SHA-1 to name their objects. +This affects both object names and object content --- both the names +of objects and all references to other objects within an object are +switched to the new hash function. + +NewHash repositories cannot be read by older versions of Git. + +Alongside the packfile, a NewHash repository stores a bidirectional +mapping between NewHash and SHA-1 object names. The mapping is generated +locally and can be verified using "git fsck". Object lookups use this +mapping to allow naming objects using either their SHA-1 and NewHash names +interchangeably. + +"git cat-file" and "git hash-object" gain options to display an object +in its sha1 form and write an object given its sha1 form. This +requires all objects referenced by that object to be present in the +object database so that they can be named using the appropriate name +(using the bidirectional hash mapping). + +Fetches from a SHA-1 based server convert the fetched objects into +NewHash form and record the mapping in the bidirectional mapping table +(see below for details). Pushes to a SHA-1 based server convert the +objects being pushed into sha1 form so the server does not have to be +aware of the hash function the client is using. + +Detailed Design +--------------- +Repository format extension +~~~~~~~~~~~~~~~~~~~~~~~~~~~ +A NewHash repository uses repository format version `1` (see +Documentation/technical/repository-version.txt) with extensions +`objectFormat` and `compatObjectFormat`: + + [core] + repositoryFormatVersion = 1 + [extensions] + objectFormat = newhash + compatObjectFormat = sha1 + +Specifying a repository format extension ensures that versions of Git +not aware of NewHash do not try to operate on these repositories, +instead producing an error message: + + $ git status + fatal: unknown repository extensions found: + objectformat + compatobjectformat + +See the "Transition plan" section below for more details on these +repository extensions. + +Object names +~~~~~~~~~~~~ +Objects can be named by their 40 hexadecimal digit sha1-name or 64 +hexadecimal digit newhash-name, plus names derived from those (see +gitrevisions(7)). + +The sha1-name of an object is the SHA-1 of the concatenation of its +type, length, a nul byte, and the object's sha1-content. This is the +traditional <sha1> used in Git to name objects. + +The newhash-name of an object is the NewHash of the concatenation of its +type, length, a nul byte, and the object's newhash-content. + +Object format +~~~~~~~~~~~~~ +The content as a byte sequence of a tag, commit, or tree object named +by sha1 and newhash differ because an object named by newhash-name refers to +other objects by their newhash-names and an object named by sha1-name +refers to other objects by their sha1-names. + +The newhash-content of an object is the same as its sha1-content, except +that objects referenced by the object are named using their newhash-names +instead of sha1-names. Because a blob object does not refer to any +other object, its sha1-content and newhash-content are the same. + +The format allows round-trip conversion between newhash-content and +sha1-content. + +Object storage +~~~~~~~~~~~~~~ +Loose objects use zlib compression and packed objects use the packed +format described in Documentation/technical/pack-format.txt, just like +today. The content that is compressed and stored uses newhash-content +instead of sha1-content. + +Pack index +~~~~~~~~~~ +Pack index (.idx) files use a new v3 format that supports multiple +hash functions. They have the following format (all integers are in +network byte order): + +- A header appears at the beginning and consists of the following: + - The 4-byte pack index signature: '\377t0c' + - 4-byte version number: 3 + - 4-byte length of the header section, including the signature and + version number + - 4-byte number of objects contained in the pack + - 4-byte number of object formats in this pack index: 2 + - For each object format: + - 4-byte format identifier (e.g., 'sha1' for SHA-1) + - 4-byte length in bytes of shortened object names. This is the + shortest possible length needed to make names in the shortened + object name table unambiguous. + - 4-byte integer, recording where tables relating to this format + are stored in this index file, as an offset from the beginning. + - 4-byte offset to the trailer from the beginning of this file. + - Zero or more additional key/value pairs (4-byte key, 4-byte + value). Only one key is supported: 'PSRC'. See the "Loose objects + and unreachable objects" section for supported values and how this + is used. All other keys are reserved. Readers must ignore + unrecognized keys. +- Zero or more NUL bytes. This can optionally be used to improve the + alignment of the full object name table below. +- Tables for the first object format: + - A sorted table of shortened object names. These are prefixes of + the names of all objects in this pack file, packed together + without offset values to reduce the cache footprint of the binary + search for a specific object name. + + - A table of full object names in pack order. This allows resolving + a reference to "the nth object in the pack file" (from a + reachability bitmap or from the next table of another object + format) to its object name. + + - A table of 4-byte values mapping object name order to pack order. + For an object in the table of sorted shortened object names, the + value at the corresponding index in this table is the index in the + previous table for that same object. + + This can be used to look up the object in reachability bitmaps or + to look up its name in another object format. + + - A table of 4-byte CRC32 values of the packed object data, in the + order that the objects appear in the pack file. This is to allow + compressed data to be copied directly from pack to pack during + repacking without undetected data corruption. + + - A table of 4-byte offset values. For an object in the table of + sorted shortened object names, the value at the corresponding + index in this table indicates where that object can be found in + the pack file. These are usually 31-bit pack file offsets, but + large offsets are encoded as an index into the next table with the + most significant bit set. + + - A table of 8-byte offset entries (empty for pack files less than + 2 GiB). Pack files are organized with heavily used objects toward + the front, so most object references should not need to refer to + this table. +- Zero or more NUL bytes. +- Tables for the second object format, with the same layout as above, + up to and not including the table of CRC32 values. +- Zero or more NUL bytes. +- The trailer consists of the following: + - A copy of the 20-byte NewHash checksum at the end of the + corresponding packfile. + + - 20-byte NewHash checksum of all of the above. + +Loose object index +~~~~~~~~~~~~~~~~~~ +A new file $GIT_OBJECT_DIR/loose-object-idx contains information about +all loose objects. Its format is + + # loose-object-idx + (newhash-name SP sha1-name LF)* + +where the object names are in hexadecimal format. The file is not +sorted. + +The loose object index is protected against concurrent writes by a +lock file $GIT_OBJECT_DIR/loose-object-idx.lock. To add a new loose +object: + +1. Write the loose object to a temporary file, like today. +2. Open loose-object-idx.lock with O_CREAT | O_EXCL to acquire the lock. +3. Rename the loose object into place. +4. Open loose-object-idx with O_APPEND and write the new object +5. Unlink loose-object-idx.lock to release the lock. + +To remove entries (e.g. in "git pack-refs" or "git-prune"): + +1. Open loose-object-idx.lock with O_CREAT | O_EXCL to acquire the + lock. +2. Write the new content to loose-object-idx.lock. +3. Unlink any loose objects being removed. +4. Rename to replace loose-object-idx, releasing the lock. + +Translation table +~~~~~~~~~~~~~~~~~ +The index files support a bidirectional mapping between sha1-names +and newhash-names. The lookup proceeds similarly to ordinary object +lookups. For example, to convert a sha1-name to a newhash-name: + + 1. Look for the object in idx files. If a match is present in the + idx's sorted list of truncated sha1-names, then: + a. Read the corresponding entry in the sha1-name order to pack + name order mapping. + b. Read the corresponding entry in the full sha1-name table to + verify we found the right object. If it is, then + c. Read the corresponding entry in the full newhash-name table. + That is the object's newhash-name. + 2. Check for a loose object. Read lines from loose-object-idx until + we find a match. + +Step (1) takes the same amount of time as an ordinary object lookup: +O(number of packs * log(objects per pack)). Step (2) takes O(number of +loose objects) time. To maintain good performance it will be necessary +to keep the number of loose objects low. See the "Loose objects and +unreachable objects" section below for more details. + +Since all operations that make new objects (e.g., "git commit") add +the new objects to the corresponding index, this mapping is possible +for all objects in the object store. + +Reading an object's sha1-content +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ +The sha1-content of an object can be read by converting all newhash-names +its newhash-content references to sha1-names using the translation table. + +Fetch +~~~~~ +Fetching from a SHA-1 based server requires translating between SHA-1 +and NewHash based representations on the fly. + +SHA-1s named in the ref advertisement that are present on the client +can be translated to NewHash and looked up as local objects using the +translation table. + +Negotiation proceeds as today. Any "have"s generated locally are +converted to SHA-1 before being sent to the server, and SHA-1s +mentioned by the server are converted to NewHash when looking them up +locally. + +After negotiation, the server sends a packfile containing the +requested objects. We convert the packfile to NewHash format using +the following steps: + +1. index-pack: inflate each object in the packfile and compute its + SHA-1. Objects can contain deltas in OBJ_REF_DELTA format against + objects the client has locally. These objects can be looked up + using the translation table and their sha1-content read as + described above to resolve the deltas. +2. topological sort: starting at the "want"s from the negotiation + phase, walk through objects in the pack and emit a list of them, + excluding blobs, in reverse topologically sorted order, with each + object coming later in the list than all objects it references. + (This list only contains objects reachable from the "wants". If the + pack from the server contained additional extraneous objects, then + they will be discarded.) +3. convert to newhash: open a new (newhash) packfile. Read the topologically + sorted list just generated. For each object, inflate its + sha1-content, convert to newhash-content, and write it to the newhash + pack. Record the new sha1<->newhash mapping entry for use in the idx. +4. sort: reorder entries in the new pack to match the order of objects + in the pack the server generated and include blobs. Write a newhash idx + file +5. clean up: remove the SHA-1 based pack file, index, and + topologically sorted list obtained from the server in steps 1 + and 2. + +Step 3 requires every object referenced by the new object to be in the +translation table. This is why the topological sort step is necessary. + +As an optimization, step 1 could write a file describing what non-blob +objects each object it has inflated from the packfile references. This +makes the topological sort in step 2 possible without inflating the +objects in the packfile for a second time. The objects need to be +inflated again in step 3, for a total of two inflations. + +Step 4 is probably necessary for good read-time performance. "git +pack-objects" on the server optimizes the pack file for good data +locality (see Documentation/technical/pack-heuristics.txt). + +Details of this process are likely to change. It will take some +experimenting to get this to perform well. + +Push +~~~~ +Push is simpler than fetch because the objects referenced by the +pushed objects are already in the translation table. The sha1-content +of each object being pushed can be read as described in the "Reading +an object's sha1-content" section to generate the pack written by git +send-pack. + +Signed Commits +~~~~~~~~~~~~~~ +We add a new field "gpgsig-newhash" to the commit object format to allow +signing commits without relying on SHA-1. It is similar to the +existing "gpgsig" field. Its signed payload is the newhash-content of the +commit object with any "gpgsig" and "gpgsig-newhash" fields removed. + +This means commits can be signed +1. using SHA-1 only, as in existing signed commit objects +2. using both SHA-1 and NewHash, by using both gpgsig-newhash and gpgsig + fields. +3. using only NewHash, by only using the gpgsig-newhash field. + +Old versions of "git verify-commit" can verify the gpgsig signature in +cases (1) and (2) without modifications and view case (3) as an +ordinary unsigned commit. + +Signed Tags +~~~~~~~~~~~ +We add a new field "gpgsig-newhash" to the tag object format to allow +signing tags without relying on SHA-1. Its signed payload is the +newhash-content of the tag with its gpgsig-newhash field and "-----BEGIN PGP +SIGNATURE-----" delimited in-body signature removed. + +This means tags can be signed +1. using SHA-1 only, as in existing signed tag objects +2. using both SHA-1 and NewHash, by using gpgsig-newhash and an in-body + signature. +3. using only NewHash, by only using the gpgsig-newhash field. + +Mergetag embedding +~~~~~~~~~~~~~~~~~~ +The mergetag field in the sha1-content of a commit contains the +sha1-content of a tag that was merged by that commit. + +The mergetag field in the newhash-content of the same commit contains the +newhash-content of the same tag. + +Submodules +~~~~~~~~~~ +To convert recorded submodule pointers, you need to have the converted +submodule repository in place. The translation table of the submodule +can be used to look up the new hash. + +Loose objects and unreachable objects +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ +Fast lookups in the loose-object-idx require that the number of loose +objects not grow too high. + +"git gc --auto" currently waits for there to be 6700 loose objects +present before consolidating them into a packfile. We will need to +measure to find a more appropriate threshold for it to use. + +"git gc --auto" currently waits for there to be 50 packs present +before combining packfiles. Packing loose objects more aggressively +may cause the number of pack files to grow too quickly. This can be +mitigated by using a strategy similar to Martin Fick's exponential +rolling garbage collection script: +https://gerrit-review.googlesource.com/c/gerrit/+/35215 + +"git gc" currently expels any unreachable objects it encounters in +pack files to loose objects in an attempt to prevent a race when +pruning them (in case another process is simultaneously writing a new +object that refers to the about-to-be-deleted object). This leads to +an explosion in the number of loose objects present and disk space +usage due to the objects in delta form being replaced with independent +loose objects. Worse, the race is still present for loose objects. + +Instead, "git gc" will need to move unreachable objects to a new +packfile marked as UNREACHABLE_GARBAGE (using the PSRC field; see +below). To avoid the race when writing new objects referring to an +about-to-be-deleted object, code paths that write new objects will +need to copy any objects from UNREACHABLE_GARBAGE packs that they +refer to to new, non-UNREACHABLE_GARBAGE packs (or loose objects). +UNREACHABLE_GARBAGE are then safe to delete if their creation time (as +indicated by the file's mtime) is long enough ago. + +To avoid a proliferation of UNREACHABLE_GARBAGE packs, they can be +combined under certain circumstances. If "gc.garbageTtl" is set to +greater than one day, then packs created within a single calendar day, +UTC, can be coalesced together. The resulting packfile would have an +mtime before midnight on that day, so this makes the effective maximum +ttl the garbageTtl + 1 day. If "gc.garbageTtl" is less than one day, +then we divide the calendar day into intervals one-third of that ttl +in duration. Packs created within the same interval can be coalesced +together. The resulting packfile would have an mtime before the end of +the interval, so this makes the effective maximum ttl equal to the +garbageTtl * 4/3. + +This rule comes from Thirumala Reddy Mutchukota's JGit change +https://git.eclipse.org/r/90465. + +The UNREACHABLE_GARBAGE setting goes in the PSRC field of the pack +index. More generally, that field indicates where a pack came from: + + - 1 (PACK_SOURCE_RECEIVE) for a pack received over the network + - 2 (PACK_SOURCE_AUTO) for a pack created by a lightweight + "gc --auto" operation + - 3 (PACK_SOURCE_GC) for a pack created by a full gc + - 4 (PACK_SOURCE_UNREACHABLE_GARBAGE) for potential garbage + discovered by gc + - 5 (PACK_SOURCE_INSERT) for locally created objects that were + written directly to a pack file, e.g. from "git add ." + +This information can be useful for debugging and for "gc --auto" to +make appropriate choices about which packs to coalesce. + +Caveats +------- +Invalid objects +~~~~~~~~~~~~~~~ +The conversion from sha1-content to newhash-content retains any +brokenness in the original object (e.g., tree entry modes encoded with +leading 0, tree objects whose paths are not sorted correctly, and +commit objects without an author or committer). This is a deliberate +feature of the design to allow the conversion to round-trip. + +More profoundly broken objects (e.g., a commit with a truncated "tree" +header line) cannot be converted but were not usable by current Git +anyway. + +Shallow clone and submodules +~~~~~~~~~~~~~~~~~~~~~~~~~~~~ +Because it requires all referenced objects to be available in the +locally generated translation table, this design does not support +shallow clone or unfetched submodules. Protocol improvements might +allow lifting this restriction. + +Alternates +~~~~~~~~~~ +For the same reason, a newhash repository cannot borrow objects from a +sha1 repository using objects/info/alternates or +$GIT_ALTERNATE_OBJECT_REPOSITORIES. + +git notes +~~~~~~~~~ +The "git notes" tool annotates objects using their sha1-name as key. +This design does not describe a way to migrate notes trees to use +newhash-names. That migration is expected to happen separately (for +example using a file at the root of the notes tree to describe which +hash it uses). + +Server-side cost +~~~~~~~~~~~~~~~~ +Until Git protocol gains NewHash support, using NewHash based storage +on public-facing Git servers is strongly discouraged. Once Git +protocol gains NewHash support, NewHash based servers are likely not +to support SHA-1 compatibility, to avoid what may be a very expensive +hash reencode during clone and to encourage peers to modernize. + +The design described here allows fetches by SHA-1 clients of a +personal NewHash repository because it's not much more difficult than +allowing pushes from that repository. This support needs to be guarded +by a configuration option --- servers like git.kernel.org that serve a +large number of clients would not be expected to bear that cost. + +Meaning of signatures +~~~~~~~~~~~~~~~~~~~~~ +The signed payload for signed commits and tags does not explicitly +name the hash used to identify objects. If some day Git adopts a new +hash function with the same length as the current SHA-1 (40 +hexadecimal digit) or NewHash (64 hexadecimal digit) objects then the +intent behind the PGP signed payload in an object signature is +unclear: + + object e7e07d5a4fcc2a203d9873968ad3e6bd4d7419d7 + type commit + tag v2.12.0 + tagger Junio C Hamano <gitster@pobox.com> 1487962205 -0800 + + Git 2.12 + +Does this mean Git v2.12.0 is the commit with sha1-name +e7e07d5a4fcc2a203d9873968ad3e6bd4d7419d7 or the commit with +new-40-digit-hash-name e7e07d5a4fcc2a203d9873968ad3e6bd4d7419d7? + +Fortunately NewHash and SHA-1 have different lengths. If Git starts +using another hash with the same length to name objects, then it will +need to change the format of signed payloads using that hash to +address this issue. + +Object names on the command line +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ +To support the transition (see Transition plan below), this design +supports four different modes of operation: + + 1. ("dark launch") Treat object names input by the user as SHA-1 and + convert any object names written to output to SHA-1, but store + objects using NewHash. This allows users to test the code with no + visible behavior change except for performance. This allows + allows running even tests that assume the SHA-1 hash function, to + sanity-check the behavior of the new mode. + + 2. ("early transition") Allow both SHA-1 and NewHash object names in + input. Any object names written to output use SHA-1. This allows + users to continue to make use of SHA-1 to communicate with peers + (e.g. by email) that have not migrated yet and prepares for mode 3. + + 3. ("late transition") Allow both SHA-1 and NewHash object names in + input. Any object names written to output use NewHash. In this + mode, users are using a more secure object naming method by + default. The disruption is minimal as long as most of their peers + are in mode 2 or mode 3. + + 4. ("post-transition") Treat object names input by the user as + NewHash and write output using NewHash. This is safer than mode 3 + because there is less risk that input is incorrectly interpreted + using the wrong hash function. + +The mode is specified in configuration. + +The user can also explicitly specify which format to use for a +particular revision specifier and for output, overriding the mode. For +example: + +git --output-format=sha1 log abac87a^{sha1}..f787cac^{newhash} + +Selection of a New Hash +----------------------- +In early 2005, around the time that Git was written, Xiaoyun Wang, +Yiqun Lisa Yin, and Hongbo Yu announced an attack finding SHA-1 +collisions in 2^69 operations. In August they published details. +Luckily, no practical demonstrations of a collision in full SHA-1 were +published until 10 years later, in 2017. + +The hash function NewHash to replace SHA-1 should be stronger than +SHA-1 was: we would like it to be trustworthy and useful in practice +for at least 10 years. + +Some other relevant properties: + +1. A 256-bit hash (long enough to match common security practice; not + excessively long to hurt performance and disk usage). + +2. High quality implementations should be widely available (e.g. in + OpenSSL). + +3. The hash function's properties should match Git's needs (e.g. Git + requires collision and 2nd preimage resistance and does not require + length extension resistance). + +4. As a tiebreaker, the hash should be fast to compute (fortunately + many contenders are faster than SHA-1). + +Some hashes under consideration are SHA-256, SHA-512/256, SHA-256x16, +K12, and BLAKE2bp-256. + +Transition plan +--------------- +Some initial steps can be implemented independently of one another: +- adding a hash function API (vtable) +- teaching fsck to tolerate the gpgsig-newhash field +- excluding gpgsig-* from the fields copied by "git commit --amend" +- annotating tests that depend on SHA-1 values with a SHA1 test + prerequisite +- using "struct object_id", GIT_MAX_RAWSZ, and GIT_MAX_HEXSZ + consistently instead of "unsigned char *" and the hardcoded + constants 20 and 40. +- introducing index v3 +- adding support for the PSRC field and safer object pruning + + +The first user-visible change is the introduction of the objectFormat +extension (without compatObjectFormat). This requires: +- implementing the loose-object-idx +- teaching fsck about this mode of operation +- using the hash function API (vtable) when computing object names +- signing objects and verifying signatures +- rejecting attempts to fetch from or push to an incompatible + repository + +Next comes introduction of compatObjectFormat: +- translating object names between object formats +- translating object content between object formats +- generating and verifying signatures in the compat format +- adding appropriate index entries when adding a new object to the + object store +- --output-format option +- ^{sha1} and ^{newhash} revision notation +- configuration to specify default input and output format (see + "Object names on the command line" above) + +The next step is supporting fetches and pushes to SHA-1 repositories: +- allow pushes to a repository using the compat format +- generate a topologically sorted list of the SHA-1 names of fetched + objects +- convert the fetched packfile to newhash format and generate an idx + file +- re-sort to match the order of objects in the fetched packfile + +The infrastructure supporting fetch also allows converting an existing +repository. In converted repositories and new clones, end users can +gain support for the new hash function without any visible change in +behavior (see "dark launch" in the "Object names on the command line" +section). In particular this allows users to verify NewHash signatures +on objects in the repository, and it should ensure the transition code +is stable in production in preparation for using it more widely. + +Over time projects would encourage their users to adopt the "early +transition" and then "late transition" modes to take advantage of the +new, more futureproof NewHash object names. + +When objectFormat and compatObjectFormat are both set, commands +generating signatures would generate both SHA-1 and NewHash signatures +by default to support both new and old users. + +In projects using NewHash heavily, users could be encouraged to adopt +the "post-transition" mode to avoid accidentally making implicit use +of SHA-1 object names. + +Once a critical mass of users have upgraded to a version of Git that +can verify NewHash signatures and have converted their existing +repositories to support verifying them, we can add support for a +setting to generate only NewHash signatures. This is expected to be at +least a year later. + +That is also a good moment to advertise the ability to convert +repositories to use NewHash only, stripping out all SHA-1 related +metadata. This improves performance by eliminating translation +overhead and security by avoiding the possibility of accidentally +relying on the safety of SHA-1. + +Updating Git's protocols to allow a server to specify which hash +functions it supports is also an important part of this transition. It +is not discussed in detail in this document but this transition plan +assumes it happens. :) + +Alternatives considered +----------------------- +Upgrading everyone working on a particular project on a flag day +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ +Projects like the Linux kernel are large and complex enough that +flipping the switch for all projects based on the repository at once +is infeasible. + +Not only would all developers and server operators supporting +developers have to switch on the same flag day, but supporting tooling +(continuous integration, code review, bug trackers, etc) would have to +be adapted as well. This also makes it difficult to get early feedback +from some project participants testing before it is time for mass +adoption. + +Using hash functions in parallel +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ +(e.g. https://public-inbox.org/git/22708.8913.864049.452252@chiark.greenend.org.uk/ ) +Objects newly created would be addressed by the new hash, but inside +such an object (e.g. commit) it is still possible to address objects +using the old hash function. +* You cannot trust its history (needed for bisectability) in the + future without further work +* Maintenance burden as the number of supported hash functions grows + (they will never go away, so they accumulate). In this proposal, by + comparison, converted objects lose all references to SHA-1. + +Signed objects with multiple hashes +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ +Instead of introducing the gpgsig-newhash field in commit and tag objects +for newhash-content based signatures, an earlier version of this design +added "hash newhash <newhash-name>" fields to strengthen the existing +sha1-content based signatures. + +In other words, a single signature was used to attest to the object +content using both hash functions. This had some advantages: +* Using one signature instead of two speeds up the signing process. +* Having one signed payload with both hashes allows the signer to + attest to the sha1-name and newhash-name referring to the same object. +* All users consume the same signature. Broken signatures are likely + to be detected quickly using current versions of git. + +However, it also came with disadvantages: +* Verifying a signed object requires access to the sha1-names of all + objects it references, even after the transition is complete and + translation table is no longer needed for anything else. To support + this, the design added fields such as "hash sha1 tree <sha1-name>" + and "hash sha1 parent <sha1-name>" to the newhash-content of a signed + commit, complicating the conversion process. +* Allowing signed objects without a sha1 (for after the transition is + complete) complicated the design further, requiring a "nohash sha1" + field to suppress including "hash sha1" fields in the newhash-content + and signed payload. + +Lazily populated translation table +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ +Some of the work of building the translation table could be deferred to +push time, but that would significantly complicate and slow down pushes. +Calculating the sha1-name at object creation time at the same time it is +being streamed to disk and having its newhash-name calculated should be +an acceptable cost. + +Document History +---------------- + +2017-03-03 +bmwill@google.com, jonathantanmy@google.com, jrnieder@gmail.com, +sbeller@google.com + +Initial version sent to +http://public-inbox.org/git/20170304011251.GA26789@aiede.mtv.corp.google.com + +2017-03-03 jrnieder@gmail.com +Incorporated suggestions from jonathantanmy and sbeller: +* describe purpose of signed objects with each hash type +* redefine signed object verification using object content under the + first hash function + +2017-03-06 jrnieder@gmail.com +* Use SHA3-256 instead of SHA2 (thanks, Linus and brian m. carlson).[1][2] +* Make sha3-based signatures a separate field, avoiding the need for + "hash" and "nohash" fields (thanks to peff[3]). +* Add a sorting phase to fetch (thanks to Junio for noticing the need + for this). +* Omit blobs from the topological sort during fetch (thanks to peff). +* Discuss alternates, git notes, and git servers in the caveats + section (thanks to Junio Hamano, brian m. carlson[4], and Shawn + Pearce). +* Clarify language throughout (thanks to various commenters, + especially Junio). + +2017-09-27 jrnieder@gmail.com, sbeller@google.com +* use placeholder NewHash instead of SHA3-256 +* describe criteria for picking a hash function. +* include a transition plan (thanks especially to Brandon Williams + for fleshing these ideas out) +* define the translation table (thanks, Shawn Pearce[5], Jonathan + Tan, and Masaya Suzuki) +* avoid loose object overhead by packing more aggressively in + "git gc --auto" + +[1] http://public-inbox.org/git/CA+55aFzJtejiCjV0e43+9oR3QuJK2PiFiLQemytoLpyJWe6P9w@mail.gmail.com/ +[2] http://public-inbox.org/git/CA+55aFz+gkAsDZ24zmePQuEs1XPS9BP_s8O7Q4wQ7LV7X5-oDA@mail.gmail.com/ +[3] http://public-inbox.org/git/20170306084353.nrns455dvkdsfgo5@sigill.intra.peff.net/ +[4] http://public-inbox.org/git/20170304224936.rqqtkdvfjgyezsht@genre.crustytoothpaste.net +[5] https://public-inbox.org/git/CAJo=hJtoX9=AyLHHpUJS7fueV9ciZ_MNpnEPHUz8Whui6g9F0A@mail.gmail.com/ diff --git a/Documentation/technical/pack-protocol.txt b/Documentation/technical/pack-protocol.txt index a34917153f..ed1eae8b83 100644 --- a/Documentation/technical/pack-protocol.txt +++ b/Documentation/technical/pack-protocol.txt @@ -199,7 +199,7 @@ 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, and disconnect, when it does not need any pack data. This can happen with the ls-remote command, and also can happen when -the client already is up-to-date. +the client already is up to date. Otherwise, it enters the negotiation phase, where the client and server determine what the minimal packfile necessary for transport is, diff --git a/Documentation/technical/trivial-merge.txt b/Documentation/technical/trivial-merge.txt index c79d4a7c47..1f1c33d0da 100644 --- a/Documentation/technical/trivial-merge.txt +++ b/Documentation/technical/trivial-merge.txt @@ -32,7 +32,7 @@ or the result. If multiple cases apply, the one used is listed first. A result which changes the index is an error if the index is not empty -and not up-to-date. +and not up to date. Entries marked '+' have stat information. Spaces marked '*' don't affect the result. @@ -65,7 +65,7 @@ empty, no entry is left for that stage). Otherwise, the given entry is left in stage 0, and there are no other entries. A result of "no merge" is an error if the index is not empty and not -up-to-date. +up to date. *empty* means that the tree must not have a directory-file conflict with the entry. diff --git a/Documentation/user-manual.txt b/Documentation/user-manual.txt index bc29298678..b4d88af133 100644 --- a/Documentation/user-manual.txt +++ b/Documentation/user-manual.txt @@ -2044,10 +2044,12 @@ If a push would not result in a <<fast-forwards,fast-forward>> of the remote branch, then it will fail with an error like: ------------------------------------------------- -error: remote 'refs/heads/master' is not an ancestor of - local 'refs/heads/master'. - Maybe you are not up-to-date and need to pull first? -error: failed to push to 'ssh://yourserver.com/~you/proj.git' + ! [rejected] master -> master (non-fast-forward) +error: failed to push some refs to '...' +hint: Updates were rejected because the tip of your current branch is behind +hint: its remote counterpart. Integrate the remote changes (e.g. +hint: 'git pull ...') before pushing again. +hint: See the 'Note about fast-forwards' in 'git push --help' for details. ------------------------------------------------- This can happen, for example, if you: @@ -2193,7 +2195,7 @@ $ cd work Linus's tree will be stored in the remote-tracking branch named origin/master, and can be updated using linkgit:git-fetch[1]; you can track other public trees using linkgit:git-remote[1] to set up a "remote" and -linkgit:git-fetch[1] to keep them up-to-date; see +linkgit:git-fetch[1] to keep them up to date; see <<repositories-and-branches>>. Now create the branches in which you are going to work; these start out |