diff options
Diffstat (limited to 'Documentation')
| -rw-r--r-- | Documentation/RelNotes/2.22.0.txt | 101 | ||||
| -rw-r--r-- | Documentation/config/user.txt | 23 | ||||
| -rw-r--r-- | Documentation/diff-format.txt | 20 | ||||
| -rw-r--r-- | Documentation/diff-generate-patch.txt | 13 | ||||
| -rw-r--r-- | Documentation/diff-options.txt | 22 | ||||
| -rw-r--r-- | Documentation/git-branch.txt | 6 | ||||
| -rw-r--r-- | Documentation/git-checkout.txt | 10 | ||||
| -rw-r--r-- | Documentation/git-diff-tree.txt | 11 | ||||
| -rw-r--r-- | Documentation/git-gc.txt | 2 | ||||
| -rw-r--r-- | Documentation/git-rebase.txt | 2 | ||||
| -rw-r--r-- | Documentation/git-submodule.txt | 4 | ||||
| -rw-r--r-- | Documentation/gitattributes.txt | 2 | ||||
| -rw-r--r-- | Documentation/githooks.txt | 4 | ||||
| -rw-r--r-- | Documentation/merge-options.txt | 11 | ||||
| -rw-r--r-- | Documentation/pretty-formats.txt | 264 | ||||
| -rw-r--r-- | Documentation/rev-list-options.txt | 7 | ||||
| -rw-r--r-- | Documentation/technical/api-trace2.txt | 1349 | ||||
| -rw-r--r-- | Documentation/technical/protocol-capabilities.txt | 18 |
18 files changed, 1736 insertions, 133 deletions
diff --git a/Documentation/RelNotes/2.22.0.txt b/Documentation/RelNotes/2.22.0.txt new file mode 100644 index 0000000..16d3110 --- /dev/null +++ b/Documentation/RelNotes/2.22.0.txt @@ -0,0 +1,101 @@ +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. + + +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. + + +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). + + * 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 b5b2ba1..0557cbb 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 cdcc17f..4d846d7 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 231105c..f10ca41 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 554a340..5ebc568 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-branch.txt b/Documentation/git-branch.txt index 3bd83a7..0cd87dd 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 8c3d412..f179b43 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-diff-tree.txt b/Documentation/git-diff-tree.txt index 43daa7c..24f32e8 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-gc.txt b/Documentation/git-gc.txt index a744249..a7c1b0f 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 5629ba4..6363d67 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-submodule.txt b/Documentation/git-submodule.txt index ba3c4df..2794e29 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 9b41f81..bdd11a2 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 9590443..5bf653c 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/merge-options.txt b/Documentation/merge-options.txt index 63a3fc0..92a7d93 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 7bfffae..0795983 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 cad711c..ca959a7 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 0000000..2de565f --- /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/protocol-capabilities.txt b/Documentation/technical/protocol-capabilities.txt index 332d209..2b267c0 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 ------- |