diff options
Diffstat (limited to 'Documentation')
26 files changed, 1823 insertions, 158 deletions
diff --git a/Documentation/RelNotes/2.22.0.txt b/Documentation/RelNotes/2.22.0.txt new file mode 100644 index 0000000000..ca774e8388 --- /dev/null +++ b/Documentation/RelNotes/2.22.0.txt @@ -0,0 +1,150 @@ +Git 2.22 Release Notes +====================== + +Updates since v2.21 +------------------- + +UI, Workflows & Features + + * "git checkout --no-overlay" can be used to trigger a new mode of + checking out paths out of the tree-ish, that allows paths that + match the pathspec that are in the current index and working tree + and are not in the tree-ish. + + * The %(trailers) formatter in "git log --format=..." now allows to + optionally pick trailers selectively by keyword, show only values, + etc. + + * Four new configuration variables {author,committer}.{name,email} + have been introduced to override user.{name,email} in more specific + cases. + + * Command-line completion (in contrib/) learned to tab-complete the + "git submodule absorbgitdirs" subcommand. + + * "git branch" learned a new subcommand "--show-current". + + * Output from "diff --cc" did not show the original paths when the + merge involved renames. A new option adds the paths in the + original trees to the output. + + * The command line completion (in contrib/) has been taught to + complete more subcommand parameters. + + * The final report from "git bisect" used to show the suspected + culprit using a raw "diff-tree", with which there is no output for + a merge commit. This has been updated to use a more modern and + human readable output that still is concise enough. + + +Performance, Internal Implementation, Development Support etc. + + * The diff machinery, one of the oldest parts of the system, which + long predates the parse-options API, uses fairly long and complex + handcrafted option parser. This is being rewritten to use the + parse-options API. + + * The implementation of pack-redundant has been updated for + performance in a repository with many packfiles. + + * A more structured way to obtain execution trace has been added. + + * "git prune" has been taught to take advantage of reachability + bitmap when able. + + * The command line parser of "git commit-tree" has been rewritten to + use the parse-options API. + + +Fixes since v2.21 +----------------- + + * "git prune-packed" did not notice and complain against excess + arguments given from the command line, which now it does. + (merge 9b0bd87ed2 rj/prune-packed-excess-args later to maint). + + * Split-index fix. + (merge 6e37c8ed3c nd/split-index-null-base-fix later to maint). + + * "git diff --no-index" may still want to access Git goodies like + --ext-diff and --textconv, but so far these have been ignored, + which has been corrected. + (merge 287ab28bfa jk/diff-no-index-initialize later to maint). + + * Unify RPC code for smart http in protocol v0/v1 and v2, which fixes + a bug in the latter (lack of authentication retry) and generally + improves the code base. + (merge a97d00799a jt/http-auth-proto-v2-fix later to maint). + + * The include file compat/bswap.h has been updated so that it is safe + to (accidentally) include it more than once. + (merge 33aa579a55 jk/guard-bswap-header later to maint). + + * The set of header files used by "make hdr-check" unconditionally + included sha256/gcrypt.h, even when it is not used, causing the + make target to fail. We now skip it when GCRYPT_SHA256 is not in + use. + (merge f23aa18e7f rj/hdr-check-gcrypt-fix later to maint). + + * The Makefile uses 'find' utility to enumerate all the *.h header + files, which is expensive on platforms with slow filesystems; it + now optionally uses "ls-files" if working within a repository, + which is a trick similar to how all sources are enumerated to run + ETAGS on. + (merge 92b88eba9f js/find-lib-h-with-ls-files-when-possible later to maint). + + * "git rebase" that was reimplemented in C did not set ORIG_HEAD + correctly, which has been corrected. + (merge cbd29ead92 js/rebase-orig-head-fix later to maint). + + * Dev support. + (merge f545737144 js/stress-test-ui-tweak later to maint). + + * CFLAGS now can be tweaked when invoking Make while using + DEVELOPER=YesPlease; this did not work well before. + (merge 6d5d4b4e93 ab/makefile-help-devs-more later to maint). + + * "git fsck --connectivity-only" omits computation necessary to sift + the objects that are not reachable from any of the refs into + unreachable and dangling. This is now enabled when dangling + objects are requested (which is done by default, but can be + overridden with the "--no-dangling" option). + (merge 8d8c2a5aef jk/fsck-doc later to maint). + + * On platforms where "git fetch" is killed with SIGPIPE (e.g. OSX), + the upload-pack that runs on the other end that hangs up after + detecting an error could cause "git fetch" to die with a signal, + which led to a flakey test. "git fetch" now ignores SIGPIPE during + the network portion of its operation (this is not a problem as we + check the return status from our write(2)s). + (merge 143588949c jk/no-sigpipe-during-network-transport later to maint). + + * A recent update broke "is this object available to us?" check for + well-known objects like an empty tree (which should yield "yes", + even when there is no on-disk object for an empty tree), which has + been corrected. + (merge f06ab027ef jk/virtual-objects-do-exist later to maint). + + * The setup code has been cleaned up to avoid leaks around the + repository_format structure. + (merge e8805af1c3 ma/clear-repository-format later to maint). + + * "git config --type=color ..." is meant to replace "git config --get-color" + but there is a slight difference that wasn't documented, which is + now fixed. + (merge cd8e7593b9 jk/config-type-color-ends-with-lf later to maint). + + * Code cleanup, docfix, build fix, etc. + (merge 11f470aee7 jc/test-yes-doc later to maint). + (merge 90503a240b js/doc-symref-in-proto-v1 later to maint). + (merge 5c326d1252 jk/unused-params later to maint). + (merge 68cabbfda3 dl/doc-submodule-wo-subcommand later to maint). + (merge 9903623761 ab/receive-pack-use-after-free-fix later to maint). + (merge 1ede45e44b en/merge-options-doc later to maint). + (merge 3e14dd2c8e rd/doc-hook-used-in-sample later to maint). + (merge c271dc28fd nd/no-more-check-racy later to maint). + (merge e6e15194a8 yb/utf-16le-bom-spellfix later to maint). + (merge bb101aaf0c rd/attr.c-comment-typofix later to maint). + (merge 716a5af812 rd/gc-prune-doc-fix later to maint). + (merge 50b206371d js/untravis-windows later to maint). + (merge dbf47215e3 js/rebase-recreate-merge later to maint). diff --git a/Documentation/config/user.txt b/Documentation/config/user.txt index b5b2ba1199..0557cbbceb 100644 --- a/Documentation/config/user.txt +++ b/Documentation/config/user.txt @@ -1,12 +1,19 @@ -user.email:: - Your email address to be recorded in any newly created commits. - Can be overridden by the `GIT_AUTHOR_EMAIL`, `GIT_COMMITTER_EMAIL`, and - `EMAIL` environment variables. See linkgit:git-commit-tree[1]. - user.name:: - Your full name to be recorded in any newly created commits. - Can be overridden by the `GIT_AUTHOR_NAME` and `GIT_COMMITTER_NAME` - environment variables. See linkgit:git-commit-tree[1]. +user.email:: +author.name:: +author.email:: +committer.name:: +committer.email:: + The `user.name` and `user.email` variables determine what ends + up in the `author` and `committer` field of commit + objects. + If you need the `author` or `committer` to be different, the + `author.name`, `author.email`, `committer.name` or + `committer.email` variables can be set. + Also, all of these can be overridden by the `GIT_AUTHOR_NAME`, + `GIT_AUTHOR_EMAIL`, `GIT_COMMITTER_NAME`, + `GIT_COMMITTER_EMAIL` and `EMAIL` environment variables. + See linkgit:git-commit-tree[1] for more information. user.useConfigOnly:: Instruct Git to avoid trying to guess defaults for `user.email` diff --git a/Documentation/diff-format.txt b/Documentation/diff-format.txt index cdcc17f0ad..4d846d7346 100644 --- a/Documentation/diff-format.txt +++ b/Documentation/diff-format.txt @@ -95,12 +95,26 @@ from the format described above in the following way: . there are more "src" modes and "src" sha1 . status is concatenated status characters for each parent . no optional "score" number -. single path, only for "dst" +. tab-separated pathname(s) of the file -Example: +For `-c` and `--cc`, only the destination or final path is shown even +if the file was renamed on any side of history. With +`--combined-all-paths`, the name of the path in each parent is shown +followed by the name of the path in the merge commit. + +Examples for `-c` and `--cc` without `--combined-all-paths`: +------------------------------------------------ +::100644 100644 100644 fabadb8 cc95eb0 4866510 MM desc.c +::100755 100755 100755 52b7a2d 6d1ac04 d2ac7d7 RM bar.sh +::100644 100644 100644 e07d6c5 9042e82 ee91881 RR phooey.c +------------------------------------------------ + +Examples when `--combined-all-paths` added to either `-c` or `--cc`: ------------------------------------------------ -::100644 100644 100644 fabadb8 cc95eb0 4866510 MM describe.c +::100644 100644 100644 fabadb8 cc95eb0 4866510 MM desc.c desc.c desc.c +::100755 100755 100755 52b7a2d 6d1ac04 d2ac7d7 RM foo.sh bar.sh bar.sh +::100644 100644 100644 e07d6c5 9042e82 ee91881 RR fooey.c fuey.c phooey.c ------------------------------------------------ Note that 'combined diff' lists only files which were modified from diff --git a/Documentation/diff-generate-patch.txt b/Documentation/diff-generate-patch.txt index 231105cff4..f10ca410ad 100644 --- a/Documentation/diff-generate-patch.txt +++ b/Documentation/diff-generate-patch.txt @@ -143,6 +143,19 @@ copying detection) are designed to work with diff of two Similar to two-line header for traditional 'unified' diff format, `/dev/null` is used to signal created or deleted files. ++ +However, if the --combined-all-paths option is provided, instead of a +two-line from-file/to-file you get a N+1 line from-file/to-file header, +where N is the number of parents in the merge commit + + --- a/file + --- a/file + --- a/file + +++ b/file ++ +This extended format can be useful if rename or copy detection is +active, to allow you to see the original name of the file in different +parents. 4. Chunk header format is modified to prevent people from accidentally feeding it to `patch -p1`. Combined diff format diff --git a/Documentation/diff-options.txt b/Documentation/diff-options.txt index 554a34080d..5ebc56867b 100644 --- a/Documentation/diff-options.txt +++ b/Documentation/diff-options.txt @@ -36,11 +36,21 @@ endif::git-format-patch[] -U<n>:: --unified=<n>:: Generate diffs with <n> lines of context instead of - the usual three. + the usual three. Implies `--patch`. ifndef::git-format-patch[] Implies `-p`. endif::git-format-patch[] +--output=<file>:: + Output to a specific file instead of stdout. + +--output-indicator-new=<char>:: +--output-indicator-old=<char>:: +--output-indicator-context=<char>:: + Specify the character used to indicate new, old or context + lines in the generated patch. Normally they are '+', '-' and + ' ' respectively. + ifndef::git-format-patch[] --raw:: ifndef::git-log[] @@ -148,6 +158,7 @@ These parameters can also be set individually with `--stat-width=<width>`, number of modified files, as well as number of added and deleted lines. +-X[<param1,param2,...>]:: --dirstat[=<param1,param2,...>]:: Output the distribution of relative amount of changes for each sub-directory. The behavior of `--dirstat` can be customized by @@ -192,6 +203,12 @@ directories with less than 10% of the total amount of changed files, and accumulating child directory counts in the parent directories: `--dirstat=files,10,cumulative`. +--cumulative:: + Synonym for --dirstat=cumulative + +--dirstat-by-file[=<param1,param2>...]:: + Synonym for --dirstat=files,param1,param2... + --summary:: Output a condensed summary of extended header information such as creations, renames and mode changes. @@ -386,6 +403,9 @@ endif::git-format-patch[] Turn off rename detection, even when the configuration file gives the default to do so. +--[no-]rename-empty:: + Whether to use empty blobs as rename source. + ifndef::git-format-patch[] --check:: Warn if changes introduce conflict markers or whitespace errors. diff --git a/Documentation/git-add.txt b/Documentation/git-add.txt index 37bcab94d5..8b0e4c7fa8 100644 --- a/Documentation/git-add.txt +++ b/Documentation/git-add.txt @@ -193,15 +193,6 @@ for "git add --no-all <pathspec>...", i.e. ignored removed files. for command-line options). -CONFIGURATION -------------- - -The optional configuration variable `core.excludesFile` indicates a path to a -file containing patterns of file names to exclude from git-add, similar to -$GIT_DIR/info/exclude. Patterns in the exclude file are used in addition to -those in info/exclude. See linkgit:gitignore[5]. - - EXAMPLES -------- diff --git a/Documentation/git-branch.txt b/Documentation/git-branch.txt index 3bd83a7cbd..0cd87ddeff 100644 --- a/Documentation/git-branch.txt +++ b/Documentation/git-branch.txt @@ -9,7 +9,7 @@ SYNOPSIS -------- [verse] 'git branch' [--color[=<when>] | --no-color] [-r | -a] - [--list] [-v [--abbrev=<length> | --no-abbrev]] + [--list] [--show-current] [-v [--abbrev=<length> | --no-abbrev]] [--column[=<options>] | --no-column] [--sort=<key>] [(--merged | --no-merged) [<commit>]] [--contains [<commit]] [--no-contains [<commit>]] @@ -160,6 +160,10 @@ This option is only applicable in non-verbose mode. branch --list 'maint-*'`, list only the branches that match the pattern(s). +--show-current:: + Print the name of the current branch. In detached HEAD state, + nothing is printed. + -v:: -vv:: --verbose:: diff --git a/Documentation/git-checkout.txt b/Documentation/git-checkout.txt index 8c3d4128c2..f179b43732 100644 --- a/Documentation/git-checkout.txt +++ b/Documentation/git-checkout.txt @@ -260,6 +260,9 @@ the conflicted merge in the specified paths. This means that you can use `git checkout -p` to selectively discard edits from your current working tree. See the ``Interactive Mode'' section of linkgit:git-add[1] to learn how to operate the `--patch` mode. ++ +Note that this option uses the no overlay mode by default (see also +`--[no-]overlay`), and currently doesn't support overlay mode. --ignore-other-worktrees:: `git checkout` refuses when the wanted ref is already checked @@ -280,6 +283,13 @@ section of linkgit:git-add[1] to learn how to operate the `--patch` mode. Do not attempt to create a branch if a remote tracking branch of the same name exists. +--[no-]overlay:: + In the default overlay mode, `git checkout` never + removes files from the index or the working tree. When + specifying `--no-overlay`, files that appear in the index and + working tree, but not in <tree-ish> are removed, to make them + match <tree-ish> exactly. + <branch>:: Branch to checkout; if it refers to a branch (i.e., a name that, when prepended with "refs/heads/", is a valid ref), then that diff --git a/Documentation/git-clean.txt b/Documentation/git-clean.txt index 03056dad0d..db876f7dde 100644 --- a/Documentation/git-clean.txt +++ b/Documentation/git-clean.txt @@ -55,14 +55,13 @@ OPTIONS -e <pattern>:: --exclude=<pattern>:: - In addition to those found in .gitignore (per directory) and - $GIT_DIR/info/exclude, also consider these patterns to be in the - set of the ignore rules in effect. + Use the given exclude pattern in addition to the standard ignore rules + (see linkgit:gitignore[5]). -x:: - Don't use the standard ignore rules read from .gitignore (per - directory) and $GIT_DIR/info/exclude, but do still use the ignore - rules given with `-e` options. This allows removing all untracked + Don't use the standard ignore rules (see linkgit:gitignore[5]), but + still use the ignore rules given with `-e` options from the command + line. This allows removing all untracked files, including build products. This can be used (possibly in conjunction with 'git reset') to create a pristine working directory to test a clean build. diff --git a/Documentation/git-commit-tree.txt b/Documentation/git-commit-tree.txt index 002dae625e..4b90b9c12a 100644 --- a/Documentation/git-commit-tree.txt +++ b/Documentation/git-commit-tree.txt @@ -23,6 +23,10 @@ Creates a new commit object based on the provided tree object and emits the new commit object id on stdout. The log message is read from the standard input, unless `-m` or `-F` options are given. +The `-m` and `-F` options can be given any number of times, in any +order. The commit log message will be composed in the order in which +the options are given. + A commit object may have any number of parents. With exactly one parent, it is an ordinary commit. Having more than one parent makes the commit a merge between several lines of history. Initial (root) @@ -41,7 +45,7 @@ state was. OPTIONS ------- <tree>:: - An existing tree object + An existing tree object. -p <parent>:: Each `-p` indicates the id of a parent commit object. @@ -52,7 +56,8 @@ OPTIONS -F <file>:: Read the commit log message from the given file. Use `-` to read - from the standard input. + from the standard input. This can be given more than once and the + content of each file becomes its own paragraph. -S[<keyid>]:: --gpg-sign[=<keyid>]:: diff --git a/Documentation/git-config.txt b/Documentation/git-config.txt index 1bfe9f56a7..d0b9c50d20 100644 --- a/Documentation/git-config.txt +++ b/Documentation/git-config.txt @@ -240,7 +240,9 @@ Valid `<type>`'s include: output. The optional `default` parameter is used instead, if there is no color configured for `name`. + -`--type=color [--default=<default>]` is preferred over `--get-color`. +`--type=color [--default=<default>]` is preferred over `--get-color` +(but note that `--get-color` will omit the trailing newline printed by +`--type=color`). -e:: --edit:: diff --git a/Documentation/git-diff-tree.txt b/Documentation/git-diff-tree.txt index 43daa7c046..24f32e8c54 100644 --- a/Documentation/git-diff-tree.txt +++ b/Documentation/git-diff-tree.txt @@ -10,8 +10,8 @@ SYNOPSIS -------- [verse] 'git diff-tree' [--stdin] [-m] [-s] [-v] [--no-commit-id] [--pretty] - [-t] [-r] [-c | --cc] [--root] [<common diff options>] - <tree-ish> [<tree-ish>] [<path>...] + [-t] [-r] [-c | --cc] [--combined-all-paths] [--root] + [<common diff options>] <tree-ish> [<tree-ish>] [<path>...] DESCRIPTION ----------- @@ -105,6 +105,13 @@ include::pretty-options.txt[] itself and the commit log message is not shown, just like in any other "empty diff" case. +--combined-all-paths:: + This flag causes combined diffs (used for merge commits) to + list the name of the file from all parents. It thus only has + effect when -c or --cc are specified, and is likely only + useful if filename changes are detected (i.e. when either + rename or copy detection have been requested). + --always:: Show the commit itself and the commit log message even if the diff itself is empty. diff --git a/Documentation/git-fsck.txt b/Documentation/git-fsck.txt index 55950d9eea..e0eae642c1 100644 --- a/Documentation/git-fsck.txt +++ b/Documentation/git-fsck.txt @@ -62,9 +62,17 @@ index file, all SHA-1 references in `refs` namespace, and all reflogs with --no-full. --connectivity-only:: - Check only the connectivity of tags, commits and tree objects. By - avoiding to unpack blobs, this speeds up the operation, at the - expense of missing corrupt objects or other problematic issues. + Check only the connectivity of reachable objects, making sure + that any objects referenced by a reachable tag, commit, or tree + is present. This speeds up the operation by avoiding reading + blobs entirely (though it does still check that referenced blobs + exist). This will detect corruption in commits and trees, but + not do any semantic checks (e.g., for format errors). Corruption + in blob objects will not be detected at all. ++ +Unreachable tags, commits, and trees will also be accessed to find the +tips of dangling segments of history. Use `--no-dangling` if you don't +care about this output and want to speed it up further. --strict:: Enable more strict checking, namely to catch a file mode diff --git a/Documentation/git-gc.txt b/Documentation/git-gc.txt index a7442499f6..a7c1b0f60e 100644 --- a/Documentation/git-gc.txt +++ b/Documentation/git-gc.txt @@ -76,7 +76,7 @@ be performed as well. --prune=<date>:: Prune loose objects older than date (default is 2 weeks ago, overridable by the config variable `gc.pruneExpire`). - --prune=all prunes loose objects regardless of their age and + --prune=now prunes loose objects regardless of their age and increases the risk of corruption if another process is writing to the repository concurrently; see "NOTES" below. --prune is on by default. diff --git a/Documentation/git-rebase.txt b/Documentation/git-rebase.txt index 5629ba4c5d..6363d674b7 100644 --- a/Documentation/git-rebase.txt +++ b/Documentation/git-rebase.txt @@ -410,7 +410,7 @@ See also INCOMPATIBLE OPTIONS below. + By default, or when `no-rebase-cousins` was specified, commits which do not have `<upstream>` as direct ancestor will keep their original branch point, -i.e. commits that would be excluded by gitlink:git-log[1]'s +i.e. commits that would be excluded by linkgit:git-log[1]'s `--ancestry-path` option will keep their original ancestry by default. If the `rebase-cousins` mode is turned on, such commits are instead rebased onto `<upstream>` (or `<onto>`, if specified). diff --git a/Documentation/git-reset.txt b/Documentation/git-reset.txt index 132f8e55f6..26e746c53f 100644 --- a/Documentation/git-reset.txt +++ b/Documentation/git-reset.txt @@ -428,8 +428,8 @@ working index HEAD target working index HEAD `reset --merge` is meant to be used when resetting out of a conflicted merge. Any mergy operation guarantees that the working tree file that is -involved in the merge does not have local change wrt the index before -it starts, and that it writes the result out to the working tree. So if +involved in the merge does not have a local change with respect to the index +before it starts, and that it writes the result out to the working tree. So if we see some difference between the index and the target and also between the index and the working tree, then it means that we are not resetting out from a state that a mergy operation left after failing diff --git a/Documentation/git-submodule.txt b/Documentation/git-submodule.txt index ba3c4df550..2794e29780 100644 --- a/Documentation/git-submodule.txt +++ b/Documentation/git-submodule.txt @@ -9,6 +9,7 @@ git-submodule - Initialize, update or inspect submodules SYNOPSIS -------- [verse] +'git submodule' [--quiet] [--cached] 'git submodule' [--quiet] add [<options>] [--] <repository> [<path>] 'git submodule' [--quiet] status [--cached] [--recursive] [--] [<path>...] 'git submodule' [--quiet] init [--] [<path>...] @@ -28,6 +29,9 @@ For more information about submodules, see linkgit:gitsubmodules[7]. COMMANDS -------- +With no arguments, shows the status of existing submodules. Several +subcommands are available to perform operations on the submodules. + add [-b <branch>] [-f|--force] [--name <name>] [--reference <repository>] [--depth <depth>] [--] <repository> [<path>]:: Add the given repository as a submodule at the given path to the changeset to be committed next to the current diff --git a/Documentation/gitattributes.txt b/Documentation/gitattributes.txt index 9b41f81c06..bdd11a2ddd 100644 --- a/Documentation/gitattributes.txt +++ b/Documentation/gitattributes.txt @@ -346,7 +346,7 @@ automatic line ending conversion based on your platform. Use the following attributes if your '*.ps1' files are UTF-16 little endian encoded without BOM and you want Git to use Windows line endings -in the working directory (use `UTF-16-LE-BOM` instead of `UTF-16LE` if +in the working directory (use `UTF-16LE-BOM` instead of `UTF-16LE` if you want UTF-16 little endian with BOM). Please note, it is highly recommended to explicitly define the line endings with `eol` if the `working-tree-encoding` diff --git a/Documentation/githooks.txt b/Documentation/githooks.txt index 959044347e..5bf653c111 100644 --- a/Documentation/githooks.txt +++ b/Documentation/githooks.txt @@ -99,6 +99,10 @@ All the `git commit` hooks are invoked with the environment variable `GIT_EDITOR=:` if the command will not bring up an editor to modify the commit message. +The default 'pre-commit' hook, when enabled--and with the +`hooks.allownonascii` config option unset or set to false--prevents +the use of non-ASCII filenames. + prepare-commit-msg ~~~~~~~~~~~~~~~~~~ diff --git a/Documentation/gitignore.txt b/Documentation/gitignore.txt index 1c94f08ff4..b5bc9dbff0 100644 --- a/Documentation/gitignore.txt +++ b/Documentation/gitignore.txt @@ -132,6 +132,14 @@ full pathname may have special meaning: - Other consecutive asterisks are considered regular asterisks and will match according to the previous rules. +CONFIGURATION +------------- + +The optional configuration variable `core.excludesFile` indicates a path to a +file containing patterns of file names to exclude, similar to +`$GIT_DIR/info/exclude`. Patterns in the exclude file are used in addition to +those in `$GIT_DIR/info/exclude`. + NOTES ----- diff --git a/Documentation/merge-options.txt b/Documentation/merge-options.txt index 63a3fc0954..92a7d936c1 100644 --- a/Documentation/merge-options.txt +++ b/Documentation/merge-options.txt @@ -3,9 +3,14 @@ Perform the merge and commit the result. This option can be used to override --no-commit. + -With --no-commit perform the merge but pretend the merge -failed and do not autocommit, to give the user a chance to -inspect and further tweak the merge result before committing. +With --no-commit perform the merge and stop just before creating +a merge commit, to give the user a chance to inspect and further +tweak the merge result before committing. ++ +Note that fast-forward updates do not create a merge commit and +therefore there is no way to stop those merges with --no-commit. +Thus, if you want to ensure your branch is not changed or updated +by the merge command, use --no-ff with --no-commit. --edit:: -e:: diff --git a/Documentation/pretty-formats.txt b/Documentation/pretty-formats.txt index 7bfffae765..079598307a 100644 --- a/Documentation/pretty-formats.txt +++ b/Documentation/pretty-formats.txt @@ -102,120 +102,160 @@ The title was >>t4119: test autocomputing -p<n> for traditional diff input.<< + The placeholders are: -- '%H': commit hash -- '%h': abbreviated commit hash -- '%T': tree hash -- '%t': abbreviated tree hash -- '%P': parent hashes -- '%p': abbreviated parent hashes -- '%an': author name -- '%aN': author name (respecting .mailmap, see linkgit:git-shortlog[1] - or linkgit:git-blame[1]) -- '%ae': author email -- '%aE': author email (respecting .mailmap, see - linkgit:git-shortlog[1] or linkgit:git-blame[1]) -- '%ad': author date (format respects --date= option) -- '%aD': author date, RFC2822 style -- '%ar': author date, relative -- '%at': author date, UNIX timestamp -- '%ai': author date, ISO 8601-like format -- '%aI': author date, strict ISO 8601 format -- '%cn': committer name -- '%cN': committer name (respecting .mailmap, see - linkgit:git-shortlog[1] or linkgit:git-blame[1]) -- '%ce': committer email -- '%cE': committer email (respecting .mailmap, see - linkgit:git-shortlog[1] or linkgit:git-blame[1]) -- '%cd': committer date (format respects --date= option) -- '%cD': committer date, RFC2822 style -- '%cr': committer date, relative -- '%ct': committer date, UNIX timestamp -- '%ci': committer date, ISO 8601-like format -- '%cI': committer date, strict ISO 8601 format -- '%d': ref names, like the --decorate option of linkgit:git-log[1] -- '%D': ref names without the " (", ")" wrapping. -- '%S': ref name given on the command line by which the commit was reached - (like `git log --source`), only works with `git log` -- '%e': encoding -- '%s': subject -- '%f': sanitized subject line, suitable for a filename -- '%b': body -- '%B': raw body (unwrapped subject and body) +- Placeholders that expand to a single literal character: +'%n':: newline +'%%':: a raw '%' +'%x00':: print a byte from a hex code + +- Placeholders that affect formatting of later placeholders: +'%Cred':: switch color to red +'%Cgreen':: switch color to green +'%Cblue':: switch color to blue +'%Creset':: reset color +'%C(...)':: color specification, as described under Values in the + "CONFIGURATION FILE" section of linkgit:git-config[1]. By + default, colors are shown only when enabled for log output + (by `color.diff`, `color.ui`, or `--color`, and respecting + the `auto` settings of the former if we are going to a + terminal). `%C(auto,...)` is accepted as a historical + synonym for the default (e.g., `%C(auto,red)`). Specifying + `%C(always,...)` will show the colors even when color is + not otherwise enabled (though consider just using + `--color=always` to enable color for the whole output, + including this format and anything else git might color). + `auto` alone (i.e. `%C(auto)`) will turn on auto coloring + on the next placeholders until the color is switched + again. +'%m':: left (`<`), right (`>`) or boundary (`-`) mark +'%w([<w>[,<i1>[,<i2>]]])':: switch line wrapping, like the -w option of + linkgit:git-shortlog[1]. +'%<(<N>[,trunc|ltrunc|mtrunc])':: make the next placeholder take at + least N columns, padding spaces on + the right if necessary. Optionally + truncate at the beginning (ltrunc), + the middle (mtrunc) or the end + (trunc) if the output is longer than + N columns. Note that truncating + only works correctly with N >= 2. +'%<|(<N>)':: make the next placeholder take at least until Nth + columns, padding spaces on the right if necessary +'%>(<N>)', '%>|(<N>)':: similar to '%<(<N>)', '%<|(<N>)' respectively, + but padding spaces on the left +'%>>(<N>)', '%>>|(<N>)':: similar to '%>(<N>)', '%>|(<N>)' + respectively, except that if the next + placeholder takes more spaces than given and + there are spaces on its left, use those + spaces +'%><(<N>)', '%><|(<N>)':: similar to '%<(<N>)', '%<|(<N>)' + respectively, but padding both sides + (i.e. the text is centered) + +- Placeholders that expand to information extracted from the commit: +'%H':: commit hash +'%h':: abbreviated commit hash +'%T':: tree hash +'%t':: abbreviated tree hash +'%P':: parent hashes +'%p':: abbreviated parent hashes +'%an':: author name +'%aN':: author name (respecting .mailmap, see linkgit:git-shortlog[1] + or linkgit:git-blame[1]) +'%ae':: author email +'%aE':: author email (respecting .mailmap, see linkgit:git-shortlog[1] + or linkgit:git-blame[1]) +'%ad':: author date (format respects --date= option) +'%aD':: author date, RFC2822 style +'%ar':: author date, relative +'%at':: author date, UNIX timestamp +'%ai':: author date, ISO 8601-like format +'%aI':: author date, strict ISO 8601 format +'%cn':: committer name +'%cN':: committer name (respecting .mailmap, see + linkgit:git-shortlog[1] or linkgit:git-blame[1]) +'%ce':: committer email +'%cE':: committer email (respecting .mailmap, see + linkgit:git-shortlog[1] or linkgit:git-blame[1]) +'%cd':: committer date (format respects --date= option) +'%cD':: committer date, RFC2822 style +'%cr':: committer date, relative +'%ct':: committer date, UNIX timestamp +'%ci':: committer date, ISO 8601-like format +'%cI':: committer date, strict ISO 8601 format +'%d':: ref names, like the --decorate option of linkgit:git-log[1] +'%D':: ref names without the " (", ")" wrapping. +'%S':: ref name given on the command line by which the commit was reached + (like `git log --source`), only works with `git log` +'%e':: encoding +'%s':: subject +'%f':: sanitized subject line, suitable for a filename +'%b':: body +'%B':: raw body (unwrapped subject and body) ifndef::git-rev-list[] -- '%N': commit notes +'%N':: commit notes endif::git-rev-list[] -- '%GG': raw verification message from GPG for a signed commit -- '%G?': show "G" for a good (valid) signature, - "B" for a bad signature, - "U" for a good signature with unknown validity, - "X" for a good signature that has expired, - "Y" for a good signature made by an expired key, - "R" for a good signature made by a revoked key, - "E" if the signature cannot be checked (e.g. missing key) - and "N" for no signature -- '%GS': show the name of the signer for a signed commit -- '%GK': show the key used to sign a signed commit -- '%GF': show the fingerprint of the key used to sign a signed commit -- '%GP': show the fingerprint of the primary key whose subkey was used - to sign a signed commit -- '%gD': reflog selector, e.g., `refs/stash@{1}` or - `refs/stash@{2 minutes ago`}; the format follows the rules described - for the `-g` option. The portion before the `@` is the refname as - given on the command line (so `git log -g refs/heads/master` would - yield `refs/heads/master@{0}`). -- '%gd': shortened reflog selector; same as `%gD`, but the refname - portion is shortened for human readability (so `refs/heads/master` - becomes just `master`). -- '%gn': reflog identity name -- '%gN': reflog identity name (respecting .mailmap, see - linkgit:git-shortlog[1] or linkgit:git-blame[1]) -- '%ge': reflog identity email -- '%gE': reflog identity email (respecting .mailmap, see - linkgit:git-shortlog[1] or linkgit:git-blame[1]) -- '%gs': reflog subject -- '%Cred': switch color to red -- '%Cgreen': switch color to green -- '%Cblue': switch color to blue -- '%Creset': reset color -- '%C(...)': color specification, as described under Values in the - "CONFIGURATION FILE" section of linkgit:git-config[1]. - By default, colors are shown only when enabled for log output (by - `color.diff`, `color.ui`, or `--color`, and respecting the `auto` - settings of the former if we are going to a terminal). `%C(auto,...)` - is accepted as a historical synonym for the default (e.g., - `%C(auto,red)`). Specifying `%C(always,...)` will show the colors - even when color is not otherwise enabled (though consider - just using `--color=always` to enable color for the whole output, - including this format and anything else git might color). `auto` - alone (i.e. `%C(auto)`) will turn on auto coloring on the next - placeholders until the color is switched again. -- '%m': left (`<`), right (`>`) or boundary (`-`) mark -- '%n': newline -- '%%': a raw '%' -- '%x00': print a byte from a hex code -- '%w([<w>[,<i1>[,<i2>]]])': switch line wrapping, like the -w option of - linkgit:git-shortlog[1]. -- '%<(<N>[,trunc|ltrunc|mtrunc])': make the next placeholder take at - least N columns, padding spaces on the right if necessary. - Optionally truncate at the beginning (ltrunc), the middle (mtrunc) - or the end (trunc) if the output is longer than N columns. - Note that truncating only works correctly with N >= 2. -- '%<|(<N>)': make the next placeholder take at least until Nth - columns, padding spaces on the right if necessary -- '%>(<N>)', '%>|(<N>)': similar to '%<(<N>)', '%<|(<N>)' - respectively, but padding spaces on the left -- '%>>(<N>)', '%>>|(<N>)': similar to '%>(<N>)', '%>|(<N>)' - respectively, except that if the next placeholder takes more spaces - than given and there are spaces on its left, use those spaces -- '%><(<N>)', '%><|(<N>)': similar to '%<(<N>)', '%<|(<N>)' - respectively, but padding both sides (i.e. the text is centered) -- %(trailers[:options]): display the trailers of the body as interpreted - by linkgit:git-interpret-trailers[1]. The `trailers` string may be - followed by a colon and zero or more comma-separated options. 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. +'%GG':: raw verification message from GPG for a signed commit +'%G?':: show "G" for a good (valid) signature, + "B" for a bad signature, + "U" for a good signature with unknown validity, + "X" for a good signature that has expired, + "Y" for a good signature made by an expired key, + "R" for a good signature made by a revoked key, + "E" if the signature cannot be checked (e.g. missing key) + and "N" for no signature +'%GS':: show the name of the signer for a signed commit +'%GK':: show the key used to sign a signed commit +'%GF':: show the fingerprint of the key used to sign a signed commit +'%GP':: show the fingerprint of the primary key whose subkey was used + to sign a signed commit +'%gD':: reflog selector, e.g., `refs/stash@{1}` or `refs/stash@{2 + minutes ago`}; the format follows the rules described for the + `-g` option. The portion before the `@` is the refname as + given on the command line (so `git log -g refs/heads/master` + would yield `refs/heads/master@{0}`). +'%gd':: shortened reflog selector; same as `%gD`, but the refname + portion is shortened for human readability (so + `refs/heads/master` becomes just `master`). +'%gn':: reflog identity name +'%gN':: reflog identity name (respecting .mailmap, see + linkgit:git-shortlog[1] or linkgit:git-blame[1]) +'%ge':: reflog identity email +'%gE':: reflog identity email (respecting .mailmap, see + linkgit:git-shortlog[1] or linkgit:git-blame[1]) +'%gs':: reflog subject +'%(trailers[:options])':: display the trailers of the body as + interpreted by + linkgit:git-interpret-trailers[1]. The + `trailers` string may be followed by a colon + and zero or more comma-separated options: +** 'key=<K>': only show trailers with specified key. Matching is done + case-insensitively and trailing colon is optional. If option is + given multiple times trailer lines matching any of the keys are + shown. This option automatically enables the `only` option so that + non-trailer lines in the trailer block are hidden. If that is not + desired it can be disabled with `only=false`. E.g., + `%(trailers:key=Reviewed-by)` shows trailer lines with key + `Reviewed-by`. +** 'only[=val]': select whether non-trailer lines from the trailer + block should be included. The `only` keyword may optionally be + followed by an equal sign and one of `true`, `on`, `yes` to omit or + `false`, `off`, `no` to show the non-trailer lines. If option is + given without value it is enabled. If given multiple times the last + value is used. +** 'separator=<SEP>': specify a separator inserted between trailer + lines. When this option is not given each trailer line is + terminated with a line feed character. The string SEP may contain + the literal formatting codes described above. To use comma as + separator one must use `%x2C` as it would otherwise be parsed as + next option. If separator option is given multiple times only the + last one is used. E.g., `%(trailers:key=Ticket,separator=%x2C )` + shows all trailer lines whose key is "Ticket" separated by a comma + and a space. +** 'unfold[=val]': make it behave as if interpret-trailer's `--unfold` + option was given. In same way as to for `only` it can be followed + by an equal sign and explicit value. E.g., + `%(trailers:only,unfold=true)` unfolds and shows all trailer lines. +** 'valueonly[=val]': skip over the key part of the trailer line and only + show the value part. Also this optionally allows explicit value. 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 cad711ce0a..ca959a7286 100644 --- a/Documentation/rev-list-options.txt +++ b/Documentation/rev-list-options.txt @@ -960,6 +960,13 @@ options may be given. See linkgit:git-diff-files[1] for more options. the parents have only two variants and the merge result picks one of them without modification. +--combined-all-paths:: + This flag causes combined diffs (used for merge commits) to + list the name of the file from all parents. It thus only has + effect when -c or --cc are specified, and is likely only + useful if filename changes are detected (i.e. when either + rename or copy detection have been requested). + -m:: This flag makes the merge commits show the full diff like regular commits; for each merge parent, a separate log entry diff --git a/Documentation/technical/api-trace2.txt b/Documentation/technical/api-trace2.txt new file mode 100644 index 0000000000..2de565fa3d --- /dev/null +++ b/Documentation/technical/api-trace2.txt @@ -0,0 +1,1349 @@ += Trace2 API + +The Trace2 API can be used to print debug, performance, and telemetry +information to stderr or a file. The Trace2 feature is inactive unless +explicitly enabled by enabling one or more Trace2 Targets. + +The Trace2 API is intended to replace the existing (Trace1) +printf-style tracing provided by the existing `GIT_TRACE` and +`GIT_TRACE_PERFORMANCE` facilities. During initial implementation, +Trace2 and Trace1 may operate in parallel. + +The Trace2 API defines a set of high-level messages with known fields, +such as (`start`: `argv`) and (`exit`: {`exit-code`, `elapsed-time`}). + +Trace2 instrumentation throughout the Git code base sends Trace2 +messages to the enabled Trace2 Targets. Targets transform these +messages content into purpose-specific formats and write events to +their data streams. In this manner, the Trace2 API can drive +many different types of analysis. + +Targets are defined using a VTable allowing easy extension to other +formats in the future. This might be used to define a binary format, +for example. + +== Trace2 Targets + +Trace2 defines the following set of Trace2 Targets. +Format details are given in a later section. + +`GIT_TR2` (NORMAL):: + + a simple printf format like GIT_TRACE. ++ +------------ +$ export GIT_TR2=~/log.normal +$ git version +git version 2.20.1.155.g426c96fcdb +------------ ++ +------------ +$ cat ~/log.normal +12:28:42.620009 common-main.c:38 version 2.20.1.155.g426c96fcdb +12:28:42.620989 common-main.c:39 start git version +12:28:42.621101 git.c:432 cmd_name version (version) +12:28:42.621215 git.c:662 exit elapsed:0.001227 code:0 +12:28:42.621250 trace2/tr2_tgt_normal.c:124 atexit elapsed:0.001265 code:0 +------------ + +`GIT_TR2_PERF` (PERF):: + + a column-based format to replace GIT_TRACE_PERFORMANCE suitable for + development and testing, possibly to complement tools like gprof. ++ +------------ +$ export GIT_TR2_PERF=~/log.perf +$ git version +git version 2.20.1.155.g426c96fcdb +------------ ++ +------------ +$ cat ~/log.perf +12:28:42.620675 common-main.c:38 | d0 | main | version | | | | | 2.20.1.155.g426c96fcdb +12:28:42.621001 common-main.c:39 | d0 | main | start | | | | | git version +12:28:42.621111 git.c:432 | d0 | main | cmd_name | | | | | version (version) +12:28:42.621225 git.c:662 | d0 | main | exit | | 0.001227 | | | code:0 +12:28:42.621259 trace2/tr2_tgt_perf.c:211 | d0 | main | atexit | | 0.001265 | | | code:0 +------------ + +`GIT_TR2_EVENT` (EVENT):: + + a JSON-based format of event data suitable for telemetry analysis. ++ +------------ +$ export GIT_TR2_EVENT=~/log.event +$ git version +git version 2.20.1.155.g426c96fcdb +------------ ++ +------------ +$ cat ~/log.event +{"event":"version","sid":"1547659722619736-11614","thread":"main","time":"2019-01-16 17:28:42.620713","file":"common-main.c","line":38,"evt":"1","exe":"2.20.1.155.g426c96fcdb"} +{"event":"start","sid":"1547659722619736-11614","thread":"main","time":"2019-01-16 17:28:42.621027","file":"common-main.c","line":39,"argv":["git","version"]} +{"event":"cmd_name","sid":"1547659722619736-11614","thread":"main","time":"2019-01-16 17:28:42.621122","file":"git.c","line":432,"name":"version","hierarchy":"version"} +{"event":"exit","sid":"1547659722619736-11614","thread":"main","time":"2019-01-16 17:28:42.621236","file":"git.c","line":662,"t_abs":0.001227,"code":0} +{"event":"atexit","sid":"1547659722619736-11614","thread":"main","time":"2019-01-16 17:28:42.621268","file":"trace2/tr2_tgt_event.c","line":163,"t_abs":0.001265,"code":0} +------------ + +== Enabling a Target + +A Trace2 Target is enabled when the corresponding environment variable +(`GIT_TR2`, `GIT_TR2_PERF`, or `GIT_TR2_EVENT`) is set. The following +values are recognized. + +`0`:: +`false`:: + + Disables the target. + +`1`:: +`true`:: + + Enables the target and writes stream to `STDERR`. + +`[2-9]`:: + + Enables the target and writes to the already opened file descriptor. + +`<absolute-pathname>`:: + + Enables the target, opens and writes to the file in append mode. + +`af_unix:[<socket_type>:]<absolute-pathname>`:: + + Enables the target, opens and writes to a Unix Domain Socket + (on platforms that support them). ++ +Socket type can be either `stream` or `dgram`. If the socket type is +omitted, Git will try both. + +== Trace2 API + +All public Trace2 functions and macros are defined in `trace2.h` and +`trace2.c`. All public symbols are prefixed with `trace2_`. + +There are no public Trace2 data structures. + +The Trace2 code also defines a set of private functions and data types +in the `trace2/` directory. These symbols are prefixed with `tr2_` +and should only be used by functions in `trace2.c`. + +== Conventions for Public Functions and Macros + +The functions defined by the Trace2 API are declared and documented +in `trace2.h`. It defines the API functions and wrapper macros for +Trace2. + +Some functions have a `_fl()` suffix to indicate that they take `file` +and `line-number` arguments. + +Some functions have a `_va_fl()` suffix to indicate that they also +take a `va_list` argument. + +Some functions have a `_printf_fl()` suffix to indicate that they also +take a varargs argument. + +There are CPP wrapper macros and ifdefs to hide most of these details. +See `trace2.h` for more details. The following discussion will only +describe the simplified forms. + +== Public API + +All Trace2 API functions send a messsage to all of the active +Trace2 Targets. This section describes the set of available +messages. + +It helps to divide these functions into groups for discussion +purposes. + +=== Basic Command Messages + +These are concerned with the lifetime of the overall git process. + +`void trace2_initialize()`:: + + Determines if any Trace2 Targets should be enabled and + initializes the Trace2 facility. This includes starting the + elapsed time clocks and thread local storage (TLS). ++ +This function emits a "version" message containing the version of git +and the Trace2 protocol. ++ +This function should be called from `main()` as early as possible in +the life of the process. + +`int trace2_is_enabled()`:: + + Returns 1 if Trace2 is enabled (at least one target is + active). + +`void trace2_cmd_start(int argc, const char **argv)`:: + + Emits a "start" message containing the process command line + arguments. + +`int trace2_cmd_exit(int exit_code)`:: + + Emits an "exit" message containing the process exit-code and + elapsed time. ++ +Returns the exit-code. + +`void trace2_cmd_error(const char *fmt, va_list ap)`:: + + Emits an "error" message containing a formatted error message. + +`void trace2_cmd_path(const char *pathname)`:: + + Emits a "cmd_path" message with the full pathname of the + current process. + +=== Command Detail Messages + +These are concerned with describing the specific Git command +after the command line, config, and environment are inspected. + +`void trace2_cmd_name(const char *name)`:: + + Emits a "cmd_name" message with the canonical name of the + command, for example "status" or "checkout". + +`void trace2_cmd_mode(const char *mode)`:: + + Emits a "cmd_mode" message with a qualifier name to further + describe the current git command. ++ +This message is intended to be used with git commands having multiple +major modes. For example, a "checkout" command can checkout a new +branch or it can checkout a single file, so the checkout code could +emit a cmd_mode message of "branch" or "file". + +`void trace2_cmd_alias(const char *alias, const char **argv_expansion)`:: + + Emits an "alias" message containing the alias used and the + argument expansion. + +`void trace2_def_param(const char *parameter, const char *value)`:: + + Emits a "def_param" message containing a key/value pair. ++ +This message is intended to report some global aspect of the current +command, such as a configuration setting or command line switch that +significantly affects program performance or behavior, such as +`core.abbrev`, `status.showUntrackedFiles`, or `--no-ahead-behind`. + +`void trace2_cmd_list_config()`:: + + Emits a "def_param" messages for "important" configuration + settings. ++ +The environment variable `GIT_TR2_CONFIG_PARAMS` can be set to a +list of patterns of important configuration settings, for example: +`core.*,remote.*.url`. This function will iterate over all config +settings and emit a "def_param" message for each match. + +`void trace2_cmd_set_config(const char *key, const char *value)`:: + + Emits a "def_param" message for a specific configuration + setting IFF it matches the `GIT_TR2_CONFIG_PARAMS` pattern. ++ +This is used to hook into `git_config_set()` and catch any +configuration changes and update a value previously reported by +`trace2_cmd_list_config()`. + +`void trace2_def_repo(struct repository *repo)`:: + + Registers a repository with the Trace2 layer. Assigns a + unique "repo-id" to `repo->trace2_repo_id`. ++ +Emits a "worktree" messages containing the repo-id and the worktree +pathname. ++ +Region and data messages (described later) may refer to this repo-id. ++ +The main/top-level repository will have repo-id value 1 (aka "r1"). ++ +The repo-id field is in anticipation of future in-proc submodule +repositories. + +=== Child Process Messages + +These are concerned with the various spawned child processes, +including shell scripts, git commands, editors, pagers, and hooks. + +`void trace2_child_start(struct child_process *cmd)`:: + + Emits a "child_start" message containing the "child-id", + "child-argv", and "child-classification". ++ +Before calling this, set `cmd->trace2_child_class` to a name +describing the type of child process, for example "editor". ++ +This function assigns a unique "child-id" to `cmd->trace2_child_id`. +This field is used later during the "child_exit" message to associate +it with the "child_start" message. ++ +This function should be called before spawning the child process. + +`void trace2_child_exit(struct child_proess *cmd, int child_exit_code)`:: + + Emits a "child_exit" message containing the "child-id", + the child's elapsed time and exit-code. ++ +The reported elapsed time includes the process creation overhead and +time spend waiting for it to exit, so it may be slightly longer than +the time reported by the child itself. ++ +This function should be called after reaping the child process. + +`int trace2_exec(const char *exe, const char **argv)`:: + + Emits a "exec" message containing the "exec-id" and the + argv of the new process. ++ +This function should be called before calling one of the `exec()` +variants, such as `execvp()`. ++ +This function returns a unique "exec-id". This value is used later +if the exec() fails and a "exec-result" message is necessary. + +`void trace2_exec_result(int exec_id, int error_code)`:: + + Emits a "exec_result" message containing the "exec-id" + and the error code. ++ +On Unix-based systems, `exec()` does not return if successful. +This message is used to indicate that the `exec()` failed and +that the current program is continuing. + +=== Git Thread Messages + +These messages are concerned with Git thread usage. + +`void trace2_thread_start(const char *thread_name)`:: + + Emits a "thread_start" message. ++ +The `thread_name` field should be a descriptive name, such as the +unique name of the thread-proc. A unique "thread-id" will be added +to the name to uniquely identify thread instances. ++ +Region and data messages (described later) may refer to this thread +name. ++ +This function must be called by the thread-proc of the new thread +(so that TLS data is properly initialized) and not by the caller +of `pthread_create()`. + +`void trace2_thread_exit()`:: + + Emits a "thread_exit" message containing the thread name + and the thread elapsed time. ++ +This function must be called by the thread-proc before it returns +(so that the coorect TLS data is used and cleaned up. It should +not be called by the caller of `pthread_join()`. + +=== Region and Data Messages + +These are concerned with recording performance data +over regions or spans of code. + +`void trace2_region_enter(const char *category, const char *label, const struct repository *repo)`:: + +`void trace2_region_enter_printf(const char *category, const char *label, const struct repository *repo, const char *fmt, ...)`:: + +`void trace2_region_enter_printf_va(const char *category, const char *label, const struct repository *repo, const char *fmt, va_list ap)`:: + + Emits a thread-relative "region_enter" message with optional + printf string. ++ +This function pushes a new region nesting stack level on the current +thread and starts a clock for the new stack frame. ++ +The `category` field is an arbitrary category name used to classify +regions by feature area, such as "status" or "index". At this time +it is only just printed along with the rest of the message. It may +be used in the future to filter messages. ++ +The `label` field is an arbitrary label used to describe the activity +being started, such as "read_recursive" or "do_read_index". ++ +The `repo` field, if set, will be used to get the "repo-id", so that +recursive oerations can be attributed to the correct repository. + +`void trace2_region_leave(const char *category, const char *label, const struct repository *repo)`:: + +`void trace2_region_leave_printf(const char *category, const char *label, const struct repository *repo, const char *fmt, ...)`:: + +`void trace2_region_leave_printf_va(const char *category, const char *label, const struct repository *repo, const char *fmt, va_list ap)`:: + + Emits a thread-relative "region_leave" message with optional + printf string. ++ +This function pops the region nesting stack on the current thread +and reports the elapsed time of the stack frame. ++ +The `category`, `label`, and `repo` fields are the same as above. +The `category` and `label` do not need to match the correpsonding +"region_enter" message, but it makes the data stream easier to +understand. + +`void trace2_data_string(const char *category, const struct repository *repo, const char *key, const char * value)`:: + +`void trace2_data_intmax(const char *category, const struct repository *repo, const char *key, intmax value)`:: + +`void trace2_data_json(const char *category, const struct repository *repo, const char *key, const struct json_writer *jw)`:: + + Emits a region- and thread-relative "data" or "data_json" message. ++ +This is a key/value pair message containing information about the +current thread, region stack, and repository. This could be used +to print the number of files in a directory during a multi-threaded +recursive tree walk. + +`void trace2_printf(const char *fmt, ...)`:: + +`void trace2_printf_va(const char *fmt, va_list ap)`:: + + Emits a region- and thread-relative "printf" message. + +== Trace2 Target Formats + +=== NORMAL Format + +NORMAL format is enabled when the `GIT_TR2` environment variable is +set. + +Events are written as lines of the form: + +------------ +[<time> SP <filename>:<line> SP+] <event-name> [[SP] <event-message>] LF +------------ + +`<event-name>`:: + + is the event name. + +`<event-message>`:: + is a free-form printf message intended for human consumption. ++ +Note that this may contain embedded LF or CRLF characters that are +not escaped, so the event may spill across multiple lines. + +If `GIT_TR2_BRIEF` is true, the `time`, `filename`, and `line` fields +are omitted. + +This target is intended to be more of a summary (like GIT_TRACE) and +less detailed than the other targets. It ignores thread, region, and +data messages, for example. + +=== PERF Format + +PERF format is enabled when the `GIT_TR2_PERF` environment variable +is set. + +Events are written as lines of the form: + +------------ +[<time> SP <filename>:<line> SP+ + BAR SP] d<depth> SP + BAR SP <thread-name> SP+ + BAR SP <event-name> SP+ + BAR SP [r<repo-id>] SP+ + BAR SP [<t_abs>] SP+ + BAR SP [<t_rel>] SP+ + BAR SP [<category>] SP+ + BAR SP DOTS* <perf-event-message> + LF +------------ + +`<depth>`:: + is the git process depth. This is the number of parent + git processes. A top-level git command has depth value "d0". + A child of it has depth value "d1". A second level child + has depth value "d2" and so on. + +`<thread-name>`:: + is a unique name for the thread. The primary thread + is called "main". Other thread names are of the form "th%d:%s" + and include a unique number and the name of the thread-proc. + +`<event-name>`:: + is the event name. + +`<repo-id>`:: + when present, is a number indicating the repository + in use. A `def_repo` event is emitted when a repository is + opened. This defines the repo-id and associated worktree. + Subsequent repo-specific events will reference this repo-id. ++ +Currently, this is always "r1" for the main repository. +This field is in anticipation of in-proc submodules in the future. + +`<t_abs>`:: + when present, is the absolute time in seconds since the + program started. + +`<t_rel>`:: + when present, is time in seconds relative to the start of + the current region. For a thread-exit event, it is the elapsed + time of the thread. + +`<category>`:: + is present on region and data events and is used to + indicate a broad category, such as "index" or "status". + +`<perf-event-message>`:: + is a free-form printf message intended for human consumption. + +------------ +15:33:33.532712 wt-status.c:2310 | d0 | main | region_enter | r1 | 0.126064 | | status | label:print +15:33:33.532712 wt-status.c:2331 | d0 | main | region_leave | r1 | 0.127568 | 0.001504 | status | label:print +------------ + +If `GIT_TR2_PERF_BRIEF` is true, the `time`, `file`, and `line` +fields are omitted. + +------------ +d0 | main | region_leave | r1 | 0.011717 | 0.009122 | index | label:preload +------------ + +The PERF target is intended for interactive performance analysis +during development and is quite noisy. + +=== EVENT Format + +EVENT format is enabled when the `GIT_TR2_EVENT` environment +variable is set. + +Each event is a JSON-object containing multiple key/value pairs +written as a single line and followed by a LF. + +------------ +'{' <key> ':' <value> [',' <key> ':' <value>]* '}' LF +------------ + +Some key/value pairs are common to all events and some are +event-specific. + +==== Common Key/Value Pairs + +The following key/value pairs are common to all events: + +------------ +{ + "event":"version", + "sid":"1547659722619736-11614", + "thread":"main", + "time":"2019-01-16 17:28:42.620713", + "file":"common-main.c", + "line":38, + ... +} +------------ + +`"event":<event>`:: + is the event name. + +`"sid":<sid>`:: + is the session-id. This is a unique string to identify the + process instance to allow all events emitted by a process to + be identified. A session-id is used instead of a PID because + PIDs are recycled by the OS. For child git processes, the + session-id is prepended with the session-id of the parent git + process to allow parent-child relationships to be identified + during post-processing. + +`"thread":<thread>`:: + is the thread name. + +`"time":<time>`:: + is the UTC time of the event. + +`"file":<filename>`:: + is source file generating the event. + +`"line":<line-number>`:: + is the integer source line number generating the event. + +`"repo":<repo-id>`:: + when present, is the integer repo-id as described previously. + +If `GIT_TR2_EVENT_BRIEF` is true, the `file` and `line` fields are omitted +from all events and the `time` field is only present on the "start" and +"atexit" events. + +==== Event-Specific Key/Value Pairs + +`"version"`:: + This event gives the version of the executable and the EVENT format. ++ +------------ +{ + "event":"version", + ... + "evt":"1", # EVENT format version + "exe":"2.20.1.155.g426c96fcdb" # git version +} +------------ + +`"start"`:: + This event contains the complete argv received by main(). ++ +------------ +{ + "event":"start", + ... + "argv":["git","version"] +} +------------ + +`"exit"`:: + This event is emitted when git calls `exit()`. ++ +------------ +{ + "event":"exit", + ... + "t_abs":0.001227, # elapsed time in seconds + "code":0 # exit code +} +------------ + +`"atexit"`:: + This event is emitted by the Trace2 `atexit` routine during + final shutdown. It should be the last event emitted by the + process. ++ +(The elapsed time reported here is greater than the time reported in +the "exit" event because it runs after all other atexit tasks have +completed.) ++ +------------ +{ + "event":"atexit", + ... + "t_abs":0.001227, # elapsed time in seconds + "code":0 # exit code +} +------------ + +`"signal"`:: + This event is emitted when the program is terminated by a user + signal. Depending on the platform, the signal event may + prevent the "atexit" event from being generated. ++ +------------ +{ + "event":"signal", + ... + "t_abs":0.001227, # elapsed time in seconds + "signal":13 # SIGTERM, SIGINT, etc. +} +------------ + +`"error"`:: + This event is emitted when one of the `error()`, `die()`, + or `usage()` functions are called. ++ +------------ +{ + "event":"error", + ... + "msg":"invalid option: --cahced", # formatted error message + "fmt":"invalid option: %s" # error format string +} +------------ ++ +The error event may be emitted more than once. The format string +allows post-processors to group errors by type without worrying +about specific error arguments. + +`"cmd_path"`:: + This event contains the discovered full path of the git + executable (on platforms that are configured to resolve it). ++ +------------ +{ + "event":"cmd_path", + ... + "path":"C:/work/gfw/git.exe" +} +------------ + +`"cmd_name"`:: + This event contains the command name for this git process + and the hierarchy of commands from parent git processes. ++ +------------ +{ + "event":"cmd_name", + ... + "name":"pack-objects", + "hierarchy":"push/pack-objects" +} +------------ ++ +Normally, the "name" field contains the canonical name of the +command. When a canonical name is not available, one of +these special values are used: ++ +------------ +"_query_" # "git --html-path" +"_run_dashed_" # when "git foo" tries to run "git-foo" +"_run_shell_alias_" # alias expansion to a shell command +"_run_git_alias_" # alias expansion to a git command +"_usage_" # usage error +------------ + +`"cmd_mode"`:: + This event, when present, describes the command variant This + event may be emitted more than once. ++ +------------ +{ + "event":"cmd_mode", + ... + "name":"branch" +} +------------ ++ +The "name" field is an arbitrary string to describe the command mode. +For example, checkout can checkout a branch or an individual file. +And these variations typically have different performance +characteristics that are not comparable. + +`"alias"`:: + This event is present when an alias is expanded. ++ +------------ +{ + "event":"alias", + ... + "alias":"l", # registered alias + "argv":["log","--graph"] # alias expansion +} +------------ + +`"child_start"`:: + This event describes a child process that is about to be + spawned. ++ +------------ +{ + "event":"child_start", + ... + "child_id":2, + "child_class":"?", + "use_shell":false, + "argv":["git","rev-list","--objects","--stdin","--not","--all","--quiet"] + + "hook_name":"<hook_name>" # present when child_class is "hook" + "cd":"<path>" # present when cd is required +} +------------ ++ +The "child_id" field can be used to match this child_start with the +corresponding child_exit event. ++ +The "child_class" field is a rough classification, such as "editor", +"pager", "transport/*", and "hook". Unclassified children are classified +with "?". + +`"child_exit"`:: + This event is generated after the current process has returned + from the waitpid() and collected the exit information from the + child. ++ +------------ +{ + "event":"child_exit", + ... + "child_id":2, + "pid":14708, # child PID + "code":0, # child exit-code + "t_rel":0.110605 # observed run-time of child process +} +------------ ++ +Note that the session-id of the child process is not available to +the current/spawning process, so the child's PID is reported here as +a hint for post-processing. (But it is only a hint because the child +proces may be a shell script which doesn't have a session-id.) ++ +Note that the `t_rel` field contains the observed run time in seconds +for the child process (starting before the fork/exec/spawn and +stopping after the waitpid() and includes OS process creation overhead). +So this time will be slightly larger than the atexit time reported by +the child process itself. + +`"exec"`:: + This event is generated before git attempts to `exec()` + another command rather than starting a child process. ++ +------------ +{ + "event":"exec", + ... + "exec_id":0, + "exe":"git", + "argv":["foo", "bar"] +} +------------ ++ +The "exec_id" field is a command-unique id and is only useful if the +`exec()` fails and a corresponding exec_result event is generated. + +`"exec_result"`:: + This event is generated if the `exec()` fails and control + returns to the current git command. ++ +------------ +{ + "event":"exec_result", + ... + "exec_id":0, + "code":1 # error code (errno) from exec() +} +------------ + +`"thread_start"`:: + This event is generated when a thread is started. It is + generated from *within* the new thread's thread-proc (for TLS + reasons). ++ +------------ +{ + "event":"thread_start", + ... + "thread":"th02:preload_thread" # thread name +} +------------ + +`"thread_exit"`:: + This event is generated when a thread exits. It is generated + from *within* the thread's thread-proc (for TLS reasons). ++ +------------ +{ + "event":"thread_exit", + ... + "thread":"th02:preload_thread", # thread name + "t_rel":0.007328 # thread elapsed time +} +------------ + +`"def_param"`:: + This event is generated to log a global parameter. ++ +------------ +{ + "event":"def_param", + ... + "param":"core.abbrev", + "value":"7" +} +------------ + +`"def_repo"`:: + This event defines a repo-id and associates it with the root + of the worktree. ++ +------------ +{ + "event":"def_repo", + ... + "repo":1, + "worktree":"/Users/jeffhost/work/gfw" +} +------------ ++ +As stated earlier, the repo-id is currently always 1, so there will +only be one def_repo event. Later, if in-proc submodules are +supported, a def_repo event should be emitted for each submodule +visited. + +`"region_enter"`:: + This event is generated when entering a region. ++ +------------ +{ + "event":"region_enter", + ... + "repo":1, # optional + "nesting":1, # current region stack depth + "category":"index", # optional + "label":"do_read_index", # optional + "msg":".git/index" # optional +} +------------ ++ +The `category` field may be used in a future enhancement to +do category-based filtering. ++ +The `GIT_TR2_EVENT_NESTING` environment variable can be used to +filter deeply nested regions and data events. It defaults to "2". + +`"region_leave"`:: + This event is generated when leaving a region. ++ +------------ +{ + "event":"region_leave", + ... + "repo":1, # optional + "t_rel":0.002876, # time spent in region in seconds + "nesting":1, # region stack depth + "category":"index", # optional + "label":"do_read_index", # optional + "msg":".git/index" # optional +} +------------ + +`"data"`:: + This event is generated to log a thread- and region-local + key/value pair. ++ +------------ +{ + "event":"data", + ... + "repo":1, # optional + "t_abs":0.024107, # absolute elapsed time + "t_rel":0.001031, # elapsed time in region/thread + "nesting":2, # region stack depth + "category":"index", + "key":"read/cache_nr", + "value":"3552" +} +------------ ++ +The "value" field may be an integer or a string. + +`"data-json"`:: + This event is generated to log a pre-formatted JSON string + containing structured data. ++ +------------ +{ + "event":"data_json", + ... + "repo":1, # optional + "t_abs":0.015905, + "t_rel":0.015905, + "nesting":1, + "category":"process", + "key":"windows/ancestry", + "value":["bash.exe","bash.exe"] +} +------------ + +== Example Trace2 API Usage + +Here is a hypothetical usage of the Trace2 API showing the intended +usage (without worrying about the actual Git details). + +Initialization:: + + Initialization happens in `main()`. Behind the scenes, an + `atexit` and `signal` handler are registered. ++ +---------------- +int main(int argc, const char **argv) +{ + int exit_code; + + trace2_initialize(); + trace2_cmd_start(argv); + + exit_code = cmd_main(argc, argv); + + trace2_cmd_exit(exit_code); + + return exit_code; +} +---------------- + +Command Details:: + + After the basics are established, additional command + information can be sent to Trace2 as it is discovered. ++ +---------------- +int cmd_checkout(int argc, const char **argv) +{ + trace2_cmd_name("checkout"); + trace2_cmd_mode("branch"); + trace2_def_repo(the_repository); + + // emit "def_param" messages for "interesting" config settings. + trace2_cmd_list_config(); + + if (do_something()) + trace2_cmd_error("Path '%s': cannot do something", path); + + return 0; +} +---------------- + +Child Processes:: + + Wrap code spawning child processes. ++ +---------------- +void run_child(...) +{ + int child_exit_code; + struct child_process cmd = CHILD_PROCESS_INIT; + ... + cmd.trace2_child_class = "editor"; + + trace2_child_start(&cmd); + child_exit_code = spawn_child_and_wait_for_it(); + trace2_child_exit(&cmd, child_exit_code); +} +---------------- ++ +For example, the following fetch command spawned ssh, index-pack, +rev-list, and gc. This example also shows that fetch took +5.199 seconds and of that 4.932 was in ssh. ++ +---------------- +$ export GIT_TR2_BRIEF=1 +$ export GIT_TR2=~/log.normal +$ git fetch origin +... +---------------- ++ +---------------- +$ cat ~/log.normal +version 2.20.1.vfs.1.1.47.g534dbe1ad1 +start git fetch origin +worktree /Users/jeffhost/work/gfw +cmd_name fetch (fetch) +child_start[0] ssh git@github.com ... +child_start[1] git index-pack ... +... (Trace2 events from child processes omitted) +child_exit[1] pid:14707 code:0 elapsed:0.076353 +child_exit[0] pid:14706 code:0 elapsed:4.931869 +child_start[2] git rev-list ... +... (Trace2 events from child process omitted) +child_exit[2] pid:14708 code:0 elapsed:0.110605 +child_start[3] git gc --auto +... (Trace2 events from child process omitted) +child_exit[3] pid:14709 code:0 elapsed:0.006240 +exit elapsed:5.198503 code:0 +atexit elapsed:5.198541 code:0 +---------------- ++ +When a git process is a (direct or indirect) child of another +git process, it inherits Trace2 context information. This +allows the child to print the command hierarchy. This example +shows gc as child[3] of fetch. When the gc process reports +its name as "gc", it also reports the hierarchy as "fetch/gc". +(In this example, trace2 messages from the child process is +indented for clarity.) ++ +---------------- +$ export GIT_TR2_BRIEF=1 +$ export GIT_TR2=~/log.normal +$ git fetch origin +... +---------------- ++ +---------------- +$ cat ~/log.normal +version 2.20.1.160.g5676107ecd.dirty +start git fetch official +worktree /Users/jeffhost/work/gfw +cmd_name fetch (fetch) +... +child_start[3] git gc --auto + version 2.20.1.160.g5676107ecd.dirty + start /Users/jeffhost/work/gfw/git gc --auto + worktree /Users/jeffhost/work/gfw + cmd_name gc (fetch/gc) + exit elapsed:0.001959 code:0 + atexit elapsed:0.001997 code:0 +child_exit[3] pid:20303 code:0 elapsed:0.007564 +exit elapsed:3.868938 code:0 +atexit elapsed:3.868970 code:0 +---------------- + +Regions:: + + Regions can be use to time an interesting section of code. ++ +---------------- +void wt_status_collect(struct wt_status *s) +{ + trace2_region_enter("status", "worktrees", s->repo); + wt_status_collect_changes_worktree(s); + trace2_region_leave("status", "worktrees", s->repo); + + trace2_region_enter("status", "index", s->repo); + wt_status_collect_changes_index(s); + trace2_region_leave("status", "index", s->repo); + + trace2_region_enter("status", "untracked", s->repo); + wt_status_collect_untracked(s); + trace2_region_leave("status", "untracked", s->repo); +} + +void wt_status_print(struct wt_status *s) +{ + trace2_region_enter("status", "print", s->repo); + switch (s->status_format) { + ... + } + trace2_region_leave("status", "print", s->repo); +} +---------------- ++ +In this example, scanning for untracked files ran from +0.012568 to ++0.027149 (since the process started) and took 0.014581 seconds. ++ +---------------- +$ export GIT_TR2_PERF_BRIEF=1 +$ export GIT_TR2_PERF=~/log.perf +$ git status +... + +$ cat ~/log.perf +d0 | main | version | | | | | 2.20.1.160.g5676107ecd.dirty +d0 | main | start | | | | | git status +d0 | main | def_repo | r1 | | | | worktree:/Users/jeffhost/work/gfw +d0 | main | cmd_name | | | | | status (status) +... +d0 | main | region_enter | r1 | 0.010988 | | status | label:worktrees +d0 | main | region_leave | r1 | 0.011236 | 0.000248 | status | label:worktrees +d0 | main | region_enter | r1 | 0.011260 | | status | label:index +d0 | main | region_leave | r1 | 0.012542 | 0.001282 | status | label:index +d0 | main | region_enter | r1 | 0.012568 | | status | label:untracked +d0 | main | region_leave | r1 | 0.027149 | 0.014581 | status | label:untracked +d0 | main | region_enter | r1 | 0.027411 | | status | label:print +d0 | main | region_leave | r1 | 0.028741 | 0.001330 | status | label:print +d0 | main | exit | | 0.028778 | | | code:0 +d0 | main | atexit | | 0.028809 | | | code:0 +---------------- ++ +Regions may be nested. This causes messages to be indented in the +PERF target, for example. +Elapsed times are relative to the start of the correpsonding nesting +level as expected. For example, if we add region message to: ++ +---------------- +static enum path_treatment read_directory_recursive(struct dir_struct *dir, + struct index_state *istate, const char *base, int baselen, + struct untracked_cache_dir *untracked, int check_only, + int stop_at_first_file, const struct pathspec *pathspec) +{ + enum path_treatment state, subdir_state, dir_state = path_none; + + trace2_region_enter_printf("dir", "read_recursive", NULL, "%.*s", baselen, base); + ... + trace2_region_leave_printf("dir", "read_recursive", NULL, "%.*s", baselen, base); + return dir_state; +} +---------------- ++ +We can further investigate the time spent scanning for untracked files. ++ +---------------- +$ export GIT_TR2_PERF_BRIEF=1 +$ export GIT_TR2_PERF=~/log.perf +$ git status +... +$ cat ~/log.perf +d0 | main | version | | | | | 2.20.1.162.gb4ccea44db.dirty +d0 | main | start | | | | | git status +d0 | main | def_repo | r1 | | | | worktree:/Users/jeffhost/work/gfw +d0 | main | cmd_name | | | | | status (status) +... +d0 | main | region_enter | r1 | 0.015047 | | status | label:untracked +d0 | main | region_enter | | 0.015132 | | dir | ..label:read_recursive +d0 | main | region_enter | | 0.016341 | | dir | ....label:read_recursive vcs-svn/ +d0 | main | region_leave | | 0.016422 | 0.000081 | dir | ....label:read_recursive vcs-svn/ +d0 | main | region_enter | | 0.016446 | | dir | ....label:read_recursive xdiff/ +d0 | main | region_leave | | 0.016522 | 0.000076 | dir | ....label:read_recursive xdiff/ +d0 | main | region_enter | | 0.016612 | | dir | ....label:read_recursive git-gui/ +d0 | main | region_enter | | 0.016698 | | dir | ......label:read_recursive git-gui/po/ +d0 | main | region_enter | | 0.016810 | | dir | ........label:read_recursive git-gui/po/glossary/ +d0 | main | region_leave | | 0.016863 | 0.000053 | dir | ........label:read_recursive git-gui/po/glossary/ +... +d0 | main | region_enter | | 0.031876 | | dir | ....label:read_recursive builtin/ +d0 | main | region_leave | | 0.032270 | 0.000394 | dir | ....label:read_recursive builtin/ +d0 | main | region_leave | | 0.032414 | 0.017282 | dir | ..label:read_recursive +d0 | main | region_leave | r1 | 0.032454 | 0.017407 | status | label:untracked +... +d0 | main | exit | | 0.034279 | | | code:0 +d0 | main | atexit | | 0.034322 | | | code:0 +---------------- ++ +Trace2 regions are similar to the existing trace_performance_enter() +and trace_performance_leave() routines, but are thread safe and +maintain per-thread stacks of timers. + +Data Messages:: + + Data messages added to a region. ++ +---------------- +int read_index_from(struct index_state *istate, const char *path, + const char *gitdir) +{ + trace2_region_enter_printf("index", "do_read_index", the_repository, "%s", path); + + ... + + trace2_data_intmax("index", the_repository, "read/version", istate->version); + trace2_data_intmax("index", the_repository, "read/cache_nr", istate->cache_nr); + + trace2_region_leave_printf("index", "do_read_index", the_repository, "%s", path); +} +---------------- ++ +This example shows that the index contained 3552 entries. ++ +---------------- +$ export GIT_TR2_PERF_BRIEF=1 +$ export GIT_TR2_PERF=~/log.perf +$ git status +... +$ cat ~/log.perf +d0 | main | version | | | | | 2.20.1.156.gf9916ae094.dirty +d0 | main | start | | | | | git status +d0 | main | def_repo | r1 | | | | worktree:/Users/jeffhost/work/gfw +d0 | main | cmd_name | | | | | status (status) +d0 | main | region_enter | r1 | 0.001791 | | index | label:do_read_index .git/index +d0 | main | data | r1 | 0.002494 | 0.000703 | index | ..read/version:2 +d0 | main | data | r1 | 0.002520 | 0.000729 | index | ..read/cache_nr:3552 +d0 | main | region_leave | r1 | 0.002539 | 0.000748 | index | label:do_read_index .git/index +... +---------------- + +Thread Events:: + + Thread messages added to a thread-proc. ++ +For example, the multithreaded preload-index code can be +instrumented with a region around the thread pool and then +per-thread start and exit events within the threadproc. ++ +---------------- +static void *preload_thread(void *_data) +{ + // start the per-thread clock and emit a message. + trace2_thread_start("preload_thread"); + + // report which chunk of the array this thread was assigned. + trace2_data_intmax("index", the_repository, "offset", p->offset); + trace2_data_intmax("index", the_repository, "count", nr); + + do { + ... + } while (--nr > 0); + ... + + // report elapsed time taken by this thread. + trace2_thread_exit(); + return NULL; +} + +void preload_index(struct index_state *index, + const struct pathspec *pathspec, + unsigned int refresh_flags) +{ + trace2_region_enter("index", "preload", the_repository); + + for (i = 0; i < threads; i++) { + ... /* create thread */ + } + + for (i = 0; i < threads; i++) { + ... /* join thread */ + } + + trace2_region_leave("index", "preload", the_repository); +} +---------------- ++ +In this example preload_index() was executed by the `main` thread +and started the `preload` region. Seven threads, named +`th01:preload_thread` through `th07:preload_thread`, were started. +Events from each thread are atomically appended to the shared target +stream as they occur so they may appear in random order with respect +other threads. Finally, the main thread waits for the threads to +finish and leaves the region. ++ +Data events are tagged with the active thread name. They are used +to report the per-thread parameters. ++ +---------------- +$ export GIT_TR2_PERF_BRIEF=1 +$ export GIT_TR2_PERF=~/log.perf +$ git status +... +$ cat ~/log.perf +... +d0 | main | region_enter | r1 | 0.002595 | | index | label:preload +d0 | th01:preload_thread | thread_start | | 0.002699 | | | +d0 | th02:preload_thread | thread_start | | 0.002721 | | | +d0 | th01:preload_thread | data | r1 | 0.002736 | 0.000037 | index | offset:0 +d0 | th02:preload_thread | data | r1 | 0.002751 | 0.000030 | index | offset:2032 +d0 | th03:preload_thread | thread_start | | 0.002711 | | | +d0 | th06:preload_thread | thread_start | | 0.002739 | | | +d0 | th01:preload_thread | data | r1 | 0.002766 | 0.000067 | index | count:508 +d0 | th06:preload_thread | data | r1 | 0.002856 | 0.000117 | index | offset:2540 +d0 | th03:preload_thread | data | r1 | 0.002824 | 0.000113 | index | offset:1016 +d0 | th04:preload_thread | thread_start | | 0.002710 | | | +d0 | th02:preload_thread | data | r1 | 0.002779 | 0.000058 | index | count:508 +d0 | th06:preload_thread | data | r1 | 0.002966 | 0.000227 | index | count:508 +d0 | th07:preload_thread | thread_start | | 0.002741 | | | +d0 | th07:preload_thread | data | r1 | 0.003017 | 0.000276 | index | offset:3048 +d0 | th05:preload_thread | thread_start | | 0.002712 | | | +d0 | th05:preload_thread | data | r1 | 0.003067 | 0.000355 | index | offset:1524 +d0 | th05:preload_thread | data | r1 | 0.003090 | 0.000378 | index | count:508 +d0 | th07:preload_thread | data | r1 | 0.003037 | 0.000296 | index | count:504 +d0 | th03:preload_thread | data | r1 | 0.002971 | 0.000260 | index | count:508 +d0 | th04:preload_thread | data | r1 | 0.002983 | 0.000273 | index | offset:508 +d0 | th04:preload_thread | data | r1 | 0.007311 | 0.004601 | index | count:508 +d0 | th05:preload_thread | thread_exit | | 0.008781 | 0.006069 | | +d0 | th01:preload_thread | thread_exit | | 0.009561 | 0.006862 | | +d0 | th03:preload_thread | thread_exit | | 0.009742 | 0.007031 | | +d0 | th06:preload_thread | thread_exit | | 0.009820 | 0.007081 | | +d0 | th02:preload_thread | thread_exit | | 0.010274 | 0.007553 | | +d0 | th07:preload_thread | thread_exit | | 0.010477 | 0.007736 | | +d0 | th04:preload_thread | thread_exit | | 0.011657 | 0.008947 | | +d0 | main | region_leave | r1 | 0.011717 | 0.009122 | index | label:preload +... +d0 | main | exit | | 0.029996 | | | code:0 +d0 | main | atexit | | 0.030027 | | | code:0 +---------------- ++ +In this example, the preload region took 0.009122 seconds. The 7 threads +took between 0.006069 and 0.008947 seconds to work on their portion of +the index. Thread "th01" worked on 508 items at offset 0. Thread "th02" +worked on 508 items at offset 2032. Thread "th04" worked on 508 itemts +at offset 508. ++ +This example also shows that thread names are assigned in a racy manner +as each thread starts and allocates TLS storage. + +== Future Work + +=== Relationship to the Existing Trace Api (api-trace.txt) + +There are a few issues to resolve before we can completely +switch to Trace2. + +* Updating existing tests that assume GIT_TRACE format messages. + +* How to best handle custom GIT_TRACE_<key> messages? + +** The GIT_TRACE_<key> mechanism allows each <key> to write to a +different file (in addition to just stderr). + +** Do we want to maintain that ability or simply write to the existing +Trace2 targets (and convert <key> to a "category"). diff --git a/Documentation/technical/directory-rename-detection.txt b/Documentation/technical/directory-rename-detection.txt index 1c0086e287..844629c8c4 100644 --- a/Documentation/technical/directory-rename-detection.txt +++ b/Documentation/technical/directory-rename-detection.txt @@ -20,8 +20,8 @@ More interesting possibilities exist, though, such as: * one side of history renames x -> z, and the other renames some file to x/e, causing the need for the merge to do a transitive rename. - * one side of history renames x -> z, but also renames all files within - x. For example, x/a -> z/alpha, x/b -> z/bravo, etc. + * one side of history renames x -> z, but also renames all files within x. + For example, x/a -> z/alpha, x/b -> z/bravo, etc. * both 'x' and 'y' being merged into a single directory 'z', with a directory rename being detected for both x->z and y->z. diff --git a/Documentation/technical/protocol-capabilities.txt b/Documentation/technical/protocol-capabilities.txt index 332d209b58..2b267c0da6 100644 --- a/Documentation/technical/protocol-capabilities.txt +++ b/Documentation/technical/protocol-capabilities.txt @@ -1,6 +1,10 @@ Git Protocol Capabilities ========================= +NOTE: this document describes capabilities for versions 0 and 1 of the pack +protocol. For version 2, please refer to the link:protocol-v2.html[protocol-v2] +doc. + Servers SHOULD support all capabilities defined in this document. On the very first line of the initial server response of either @@ -172,6 +176,20 @@ agent strings are purely informative for statistics and debugging purposes, and MUST NOT be used to programmatically assume the presence or absence of particular features. +symref +------ + +This parameterized capability is used to inform the receiver which symbolic ref +points to which ref; for example, "symref=HEAD:refs/heads/master" tells the +receiver that HEAD points to master. This capability can be repeated to +represent multiple symrefs. + +Servers SHOULD include this capability for the HEAD symref if it is one of the +refs being sent. + +Clients MAY use the parameters from this capability to select the proper initial +branch when cloning a repository. + shallow ------- |