diff options
Diffstat (limited to 'Documentation')
36 files changed, 1248 insertions, 109 deletions
diff --git a/Documentation/Makefile b/Documentation/Makefile index 6232143..fa9e5c0 100644 --- a/Documentation/Makefile +++ b/Documentation/Makefile @@ -78,6 +78,7 @@ TECH_DOCS += technical/pack-heuristics TECH_DOCS += technical/pack-protocol TECH_DOCS += technical/protocol-capabilities TECH_DOCS += technical/protocol-common +TECH_DOCS += technical/protocol-v2 TECH_DOCS += technical/racy-git TECH_DOCS += technical/send-pack-pipeline TECH_DOCS += technical/shallow diff --git a/Documentation/RelNotes/2.18.0.txt b/Documentation/RelNotes/2.18.0.txt new file mode 100644 index 0000000..31c3f6d --- /dev/null +++ b/Documentation/RelNotes/2.18.0.txt @@ -0,0 +1,200 @@ +Git 2.18 Release Notes +====================== + +Updates since v2.17 +------------------- + +UI, Workflows & Features + + * Rename detection logic in "diff" family that is used in "merge" has + learned to guess when all of x/a, x/b and x/c have moved to z/a, + z/b and z/c, it is likely that x/d added in the meantime would also + want to move to z/d by taking the hint that the entire directory + 'x' moved to 'z'. A bug causing dirty files involved in a rename + to be overwritten during merge has also been fixed as part of this + work. + + * "git filter-branch" learned to use a different exit code to allow + the callers to tell the case where there was no new commits to + rewrite from other error cases. + + * When built with more recent cURL, GIT_SSL_VERSION can now specify + "tlsv1.3" as its value. + + * "git gui" learned that "~/.ssh/id_ecdsa.pub" and + "~/.ssh/id_ed25519.pub" are also possible SSH key files. + (merge 2e2f0288ef bb/git-gui-ssh-key-files later to maint). + + * "git gui" performs commit upon CTRL/CMD+ENTER but the + CTRL/CMD+KP_ENTER (i.e. enter key on the numpad) did not have the + same key binding. It now does. + (merge 28a1d94a06 bp/git-gui-bind-kp-enter later to maint). + + * "git gui" has been taught to work with old versions of tk (like + 8.5.7) that do not support "ttk::style theme use" as a way to query + the current theme. + (merge 4891961105 cb/git-gui-ttk-style later to maint). + + * "git rebase" has learned to honor "--signoff" option when using + backends other than "am" (but not "--preserve-merges"). + + * "git branch --list" during an interrupted "rebase -i" now lets + users distinguish the case where a detached HEAD is being rebased + and a normal branch is being rebased. + + * "git mergetools" learned talking to guiffy. + + +Performance, Internal Implementation, Development Support etc. + + * A "git fetch" from a repository with insane number of refs into a + repository that is already up-to-date still wasted too many cycles + making many lstat(2) calls to see if these objects at the tips + exist as loose objects locally. These lstat(2) calls are optimized + away by enumerating all loose objects beforehand. + It is unknown if the new strategy negatively affects existing use + cases, fetching into a repository with many loose objects from a + repository with small number of refs. + + * Git can be built to use either v1 or v2 of the PCRE library, and so + far, the build-time configuration USE_LIBPCRE=YesPlease instructed + the build procedure to use v1, but now it means v2. USE_LIBPCRE1 + and USE_LIBPCRE2 can be used to explicitly choose which version to + use, as before. + + * The build procedure learned to optionally use symbolic links + (instead of hardlinks and copies) to install "git-foo" for built-in + commands, whose binaries are all identical. + + * Conversion from uchar[20] to struct object_id continues. + + * The way "git worktree prune" worked internally has been simplified, + by assuming how "git worktree move" moves an existing worktree to a + different place. + + * Code clean-up for the "repository" abstraction. + (merge 00a3da2a13 nd/remove-ignore-env-field later to maint). + + * Code to find the length to uniquely abbreviate object names based + on packfile content, which is a relatively recent addtion, has been + optimized to use the same fan-out table. + + * The mechanism to use parse-options API to automate the command line + completion continues to get extended and polished. + + * Copies of old scripted Porcelain commands in contrib/examples/ have + been removed. + + * Some tests that rely on the exact hardcoded values of object names + have been updated in preparation for hash function migration. + + * Perf-test update. + + * Test helper update. + + * The effort continues to refactor the internal global data structure + to make it possible to open multiple repositories, work with and + then close them, + + * Small test-helper programs have been consolidated into a single + binary. + + * API clean-up around ref-filter code. + + * Shell completion (in contrib) that gives list of paths have been + optimized somewhat. + + * The index file is updated to record the fsmonitor section after a + full scan was made, to avoid wasting the effort that has already + spent. + + * Performance measuring framework in t/perf learned to help bisecting + performance regressions. + + * Some multi-word source filenames are being renamed to separate + words with dashes instead of underscores. + + * An reusable "memory pool" implementation has been extracted from + fast-import.c, which in turn has become the first user of the + mem-pool API. + +Also contains various documentation updates and code clean-ups. + + +Fixes since v2.17 +----------------- + + * "git shortlog cruft" aborted with a BUG message when run outside a + Git repository. The command has been taught to complain about + extra and unwanted arguments on its command line instead in such a + case. + (merge 4aa0161e83 ma/shortlog-revparse later to maint). + + * "git stash push -u -- <pathspec>" gave an unnecessary and confusing + error message when there was no tracked files that match the + <pathspec>, which has been fixed. + (merge 353278687e tg/stash-untracked-with-pathspec-fix later to maint). + + * "git tag --contains no-such-commit" gave a full list of options + after giving an error message. + (merge 3bb0923f06 ps/contains-id-error-message later to maint). + + * "diff-highlight" filter (in contrib/) learned to undertand "git log + --graph" output better. + (merge 4551fbba14 jk/diff-highlight-graph-fix later to maint). + + * when refs that do not point at committish are given, "git + filter-branch" gave a misleading error messages. This has been + corrected. + (merge f78ab355e7 yk/filter-branch-non-committish-refs later to maint). + + * "git submodule status" misbehaved on a submodule that has been + removed from the working tree. + (merge 74b6bda32f rs/status-with-removed-submodule later to maint). + + * When credential helper exits very quickly without reading its + input, it used to cause Git to die with SIGPIPE, which has been + fixed. + (merge a0d51e8d0e eb/cred-helper-ignore-sigpipe later to maint). + + * "git rebase --keep-empty" still removed an empty commit if the + other side contained an empty commit (due to the "does an + equivalent patch exist already?" check), which has been corrected. + (merge 3d946165e1 pw/rebase-keep-empty-fixes later to maint). + + * Some codepaths, including the refs API, get and keep relative + paths, that go out of sync when the process does chdir(2). The + chdir-notify API is introduced to let these codepaths adjust these + cached paths to the new current directory. + (merge fb9c2d2703 jk/relative-directory-fix later to maint). + + * "cd sub/dir && git commit ../path" ought to record the changes to + the file "sub/path", but this regressed long time ago. + (merge 86238e07ef bw/commit-partial-from-subdirectory-fix later to maint). + + * Recent introduction of "--log-destination" option to "git daemon" + did not work well when the daemon was run under "--inetd" mode. + (merge e67d906d73 lw/daemon-log-destination later to maint). + + * Small fix to the autoconf build procedure. + (merge 249482daf0 es/fread-reads-dir-autoconf-fix later to maint). + + * Fix an unexploitable (because the oversized contents are not under + attacker's control) buffer overflow. + (merge d8579accfa bp/fsmonitor-bufsize-fix later to maint). + + * Other minor doc, test and build updates and code cleanups. + (merge 248f66ed8e nd/trace-with-env later to maint). + (merge 14ced5562c ys/bisect-object-id-missing-conversion-fix later to maint). + (merge 5988eb631a ab/doc-hash-brokenness later to maint). + (merge a4d4e32a70 pk/test-avoid-pipe-hiding-exit-status later to maint). + (merge 05e293c1ac jk/flockfile-stdio later to maint). + (merge e9184b0789 jk/t5561-missing-curl later to maint). + (merge b1801b85a3 nd/worktree-move later to maint). + (merge bbd374dd20 ak/bisect-doc-typofix later to maint). + (merge 4855f06fb3 mn/send-email-credential-doc later to maint). + (merge 8523b1e355 en/doc-typoes later to maint). + (merge 43b44ccfe7 js/t5404-path-fix later to maint). + (merge decf711fc1 ps/test-chmtime-get later to maint). + (merge 22d11a6e8e es/worktree-docs later to maint). + (merge 92a5dbbc22 tg/use-git-contacts later to maint). diff --git a/Documentation/SubmittingPatches b/Documentation/SubmittingPatches index a1d0fec..945f8ed 100644 --- a/Documentation/SubmittingPatches +++ b/Documentation/SubmittingPatches @@ -260,8 +260,8 @@ that starts with `-----BEGIN PGP SIGNED MESSAGE-----`. That is not a text/plain, it's something else. Send your patch with "To:" set to the mailing list, with "cc:" listing -people who are involved in the area you are touching (the output from -`git blame $path` and `git shortlog --no-merges $path` would help to +people who are involved in the area you are touching (the `git +contacts` command in `contrib/contacts/` can help to identify them), to solicit comments and reviews. :1: footnote:[The current maintainer: gitster@pobox.com] diff --git a/Documentation/config.txt b/Documentation/config.txt index 4e0cff8..8213c12 100644 --- a/Documentation/config.txt +++ b/Documentation/config.txt @@ -530,6 +530,12 @@ core.autocrlf:: This variable can be set to 'input', in which case no output conversion is performed. +core.checkRoundtripEncoding:: + A comma and/or whitespace separated list of encodings that Git + performs UTF-8 round trip checks on if they are used in an + `working-tree-encoding` attribute (see linkgit:gitattributes[5]). + The default value is `SHIFT-JIS`. + core.symlinks:: If false, symbolic links are checked out as small plain files that contain the link text. linkgit:git-update-index[1] and @@ -898,6 +904,10 @@ core.notesRef:: This setting defaults to "refs/notes/commits", and it can be overridden by the `GIT_NOTES_REF` environment variable. See linkgit:git-notes[1]. +core.commitGraph:: + Enable git commit graph feature. Allows reading from the + commit-graph file. + core.sparseCheckout:: Enable "sparse checkout" feature. See section "Sparse checkout" in linkgit:git-read-tree[1] for more information. @@ -1957,6 +1967,7 @@ http.sslVersion:: - tlsv1.0 - tlsv1.1 - tlsv1.2 + - tlsv1.3 + Can be overridden by the `GIT_SSL_VERSION` environment variable. diff --git a/Documentation/diff-options.txt b/Documentation/diff-options.txt index e3a44f0..f466600 100644 --- a/Documentation/diff-options.txt +++ b/Documentation/diff-options.txt @@ -568,7 +568,7 @@ the normal order. -- + Patterns have the same syntax and semantics as patterns used for -fnmantch(3) without the FNM_PATHNAME flag, except a pathname also +fnmatch(3) without the FNM_PATHNAME flag, except a pathname also matches a pattern if removing any number of the final pathname components matches the pattern. For example, the pattern "`foo*bar`" matches "`fooasdfbar`" and "`foo/bar/baz/asdf`" but not "`foobarx`". @@ -592,7 +592,7 @@ endif::git-format-patch[] Treat all files as text. --ignore-cr-at-eol:: - Ignore carrige-return at the end of line when doing a comparison. + Ignore carriage-return at the end of line when doing a comparison. --ignore-space-at-eol:: Ignore changes in whitespace at EOL. diff --git a/Documentation/git-bisect.txt b/Documentation/git-bisect.txt index 4a1417b..4b45d83 100644 --- a/Documentation/git-bisect.txt +++ b/Documentation/git-bisect.txt @@ -165,8 +165,8 @@ To get a reminder of the currently used terms, use git bisect terms ------------------------------------------------ -You can get just the old (respectively new) term with `git bisect term ---term-old` or `git bisect term --term-good`. +You can get just the old (respectively new) term with `git bisect terms +--term-old` or `git bisect terms --term-good`. If you would like to use your own terms instead of "bad"/"good" or "new"/"old", you can choose any names you like (except existing bisect diff --git a/Documentation/git-commit-graph.txt b/Documentation/git-commit-graph.txt new file mode 100644 index 0000000..4c97b55 --- /dev/null +++ b/Documentation/git-commit-graph.txt @@ -0,0 +1,94 @@ +git-commit-graph(1) +=================== + +NAME +---- +git-commit-graph - Write and verify Git commit graph files + + +SYNOPSIS +-------- +[verse] +'git commit-graph read' [--object-dir <dir>] +'git commit-graph write' <options> [--object-dir <dir>] + + +DESCRIPTION +----------- + +Manage the serialized commit graph file. + + +OPTIONS +------- +--object-dir:: + Use given directory for the location of packfiles and commit graph + file. This parameter exists to specify the location of an alternate + that only has the objects directory, not a full .git directory. The + commit graph file is expected to be at <dir>/info/commit-graph and + the packfiles are expected to be in <dir>/pack. + + +COMMANDS +-------- +'write':: + +Write a commit graph file based on the commits found in packfiles. ++ +With the `--stdin-packs` option, generate the new commit graph by +walking objects only in the specified pack-indexes. (Cannot be combined +with --stdin-commits.) ++ +With the `--stdin-commits` option, generate the new commit graph by +walking commits starting at the commits specified in stdin as a list +of OIDs in hex, one OID per line. (Cannot be combined with +--stdin-packs.) ++ +With the `--append` option, include all commits that are present in the +existing commit-graph file. + +'read':: + +Read a graph file given by the commit-graph file and output basic +details about the graph file. Used for debugging purposes. + + +EXAMPLES +-------- + +* Write a commit graph file for the packed commits in your local .git folder. ++ +------------------------------------------------ +$ git commit-graph write +------------------------------------------------ + +* Write a graph file, extending the current graph file using commits +* in <pack-index>. ++ +------------------------------------------------ +$ echo <pack-index> | git commit-graph write --stdin-packs +------------------------------------------------ + +* Write a graph file containing all reachable commits. ++ +------------------------------------------------ +$ git show-ref -s | git commit-graph write --stdin-commits +------------------------------------------------ + +* Write a graph file containing all commits in the current +* commit-graph file along with those reachable from HEAD. ++ +------------------------------------------------ +$ git rev-parse HEAD | git commit-graph write --stdin-commits --append +------------------------------------------------ + +* Read basic information from the commit-graph file. ++ +------------------------------------------------ +$ git commit-graph read +------------------------------------------------ + + +GIT +--- +Part of the linkgit:git[1] suite diff --git a/Documentation/git-config.txt b/Documentation/git-config.txt index e09ed5d..18ddc78 100644 --- a/Documentation/git-config.txt +++ b/Documentation/git-config.txt @@ -9,13 +9,13 @@ git-config - Get and set repository or global options SYNOPSIS -------- [verse] -'git config' [<file-option>] [type] [--show-origin] [-z|--null] name [value [value_regex]] -'git config' [<file-option>] [type] --add name value -'git config' [<file-option>] [type] --replace-all name value [value_regex] -'git config' [<file-option>] [type] [--show-origin] [-z|--null] --get name [value_regex] -'git config' [<file-option>] [type] [--show-origin] [-z|--null] --get-all name [value_regex] -'git config' [<file-option>] [type] [--show-origin] [-z|--null] [--name-only] --get-regexp name_regex [value_regex] -'git config' [<file-option>] [type] [-z|--null] --get-urlmatch name URL +'git config' [<file-option>] [--type=<type>] [--show-origin] [-z|--null] name [value [value_regex]] +'git config' [<file-option>] [--type=<type>] --add name value +'git config' [<file-option>] [--type=<type>] --replace-all name value [value_regex] +'git config' [<file-option>] [--type=<type>] [--show-origin] [-z|--null] --get name [value_regex] +'git config' [<file-option>] [--type=<type>] [--show-origin] [-z|--null] --get-all name [value_regex] +'git config' [<file-option>] [--type=<type>] [--show-origin] [-z|--null] [--name-only] --get-regexp name_regex [value_regex] +'git config' [<file-option>] [--type=<type>] [-z|--null] --get-urlmatch name URL 'git config' [<file-option>] --unset name [value_regex] 'git config' [<file-option>] --unset-all name [value_regex] 'git config' [<file-option>] --rename-section old_name new_name @@ -38,12 +38,10 @@ existing values that match the regexp are updated or unset. If you want to handle the lines that do *not* match the regex, just prepend a single exclamation mark in front (see also <<EXAMPLES>>). -The type specifier can be either `--int` or `--bool`, to make -'git config' ensure that the variable(s) are of the given type and -convert the value to the canonical form (simple decimal number for int, -a "true" or "false" string for bool), or `--path`, which does some -path expansion (see `--path` below). If no type specifier is passed, no -checks or transformations are performed on the value. +The `--type=<type>` option instructs 'git config' to ensure that incoming and +outgoing values are canonicalize-able under the given <type>. If no +`--type=<type>` is given, no canonicalization will be performed. Callers may +unset an existing `--type` specifier with `--no-type`. When reading, the values are read from the system, global and repository local configuration files by default, and options @@ -160,30 +158,43 @@ See also <<FILES>>. --list:: List all variables set in config file, along with their values. ---bool:: - 'git config' will ensure that the output is "true" or "false" +--type <type>:: + 'git config' will ensure that any input or output is valid under the given + type constraint(s), and will canonicalize outgoing values in `<type>`'s + canonical form. ++ +Valid `<type>`'s include: ++ +- 'bool': canonicalize values as either "true" or "false". +- 'int': canonicalize values as simple decimal numbers. An optional suffix of + 'k', 'm', or 'g' will cause the value to be multiplied by 1024, 1048576, or + 1073741824 upon input. +- 'bool-or-int': canonicalize according to either 'bool' or 'int', as described + above. +- 'path': canonicalize by adding a leading `~` to the value of `$HOME` and + `~user` to the home directory for the specified user. This specifier has no + effect when setting the value (but you can use `git config section.variable + ~/` from the command line to let your shell do the expansion.) +- 'expiry-date': canonicalize by converting from a fixed or relative date-string + to a timestamp. This specifier has no effect when setting the value. +- 'color': When getting a value, canonicalize by converting to an ANSI color + escape sequence. When setting a value, a sanity-check is performed to ensure + that the given value is canonicalize-able as an ANSI color, but it is written + as-is. ++ +--bool:: --int:: - 'git config' will ensure that the output is a simple - decimal number. An optional value suffix of 'k', 'm', or 'g' - in the config file will cause the value to be multiplied - by 1024, 1048576, or 1073741824 prior to output. - --bool-or-int:: - 'git config' will ensure that the output matches the format of - either --bool or --int, as described above. - --path:: - `git config` will expand a leading `~` to the value of - `$HOME`, and `~user` to the home directory for the - specified user. This option has no effect when setting the - value (but you can use `git config section.variable ~/` - from the command line to let your shell do the expansion). - --expiry-date:: - `git config` will ensure that the output is converted from - a fixed or relative date-string to a timestamp. This option - has no effect when setting the value. + Historical options for selecting a type specifier. Prefer instead `--type`, + (see: above). + +--no-type:: + Un-sets the previously set type specifier (if one was previously set). This + option requests that 'git config' not canonicalize the retrieved variable. + `--no-type` has no effect without `--type=<type>` or `--<type>`. -z:: --null:: @@ -221,6 +232,8 @@ See also <<FILES>>. output it as the ANSI color escape sequence to the standard 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`. -e:: --edit:: @@ -233,6 +246,10 @@ See also <<FILES>>. using `--file`, `--global`, etc) and `on` when searching all config files. +--default <value>:: + When using `--get`, and the requested variable is not found, behave as if + <value> were the value assigned to the that variable. + CONFIGURATION ------------- `pager.config` is only respected when listing configuration, i.e., when diff --git a/Documentation/git-fetch-pack.txt b/Documentation/git-fetch-pack.txt index f7ebe36..c975884 100644 --- a/Documentation/git-fetch-pack.txt +++ b/Documentation/git-fetch-pack.txt @@ -88,7 +88,7 @@ be in a separate packet, and the list must end with a flush packet. infinite even if there is an ancestor-chain that long. --shallow-since=<date>:: - Deepen or shorten the history of a shallow'repository to + Deepen or shorten the history of a shallow repository to include all reachable commits after <date>. --shallow-exclude=<revision>:: diff --git a/Documentation/git-filter-branch.txt b/Documentation/git-filter-branch.txt index 3a52e4d..b634043 100644 --- a/Documentation/git-filter-branch.txt +++ b/Documentation/git-filter-branch.txt @@ -222,6 +222,14 @@ this purpose, they are instead rewritten to point at the nearest ancestor that was not excluded. +EXIT STATUS +----------- + +On success, the exit status is `0`. If the filter can't find any commits to +rewrite, the exit status is `2`. On any other error, the exit status may be +any other non-zero value. + + Examples -------- diff --git a/Documentation/git-for-each-ref.txt b/Documentation/git-for-each-ref.txt index dffa14a..085d177 100644 --- a/Documentation/git-for-each-ref.txt +++ b/Documentation/git-for-each-ref.txt @@ -121,7 +121,7 @@ refname:: stripping with positive <N>, or it becomes the full refname if stripping with negative <N>. Neither is an error. + -`strip` can be used as a synomym to `lstrip`. +`strip` can be used as a synonym to `lstrip`. objecttype:: The type of the object (`blob`, `tree`, `commit`, `tag`). diff --git a/Documentation/git-format-patch.txt b/Documentation/git-format-patch.txt index 6cbe462..b41e132 100644 --- a/Documentation/git-format-patch.txt +++ b/Documentation/git-format-patch.txt @@ -47,7 +47,7 @@ There are two ways to specify which commits to operate on. The first rule takes precedence in the case of a single <commit>. To apply the second rule, i.e., format everything since the beginning of -history up until <commit>, use the '\--root' option: `git format-patch +history up until <commit>, use the `--root` option: `git format-patch --root <commit>`. If you want to format only <commit> itself, you can do this with `git format-patch -1 <commit>`. diff --git a/Documentation/git-gc.txt b/Documentation/git-gc.txt index 571b5a7..7c8a2ed 100644 --- a/Documentation/git-gc.txt +++ b/Documentation/git-gc.txt @@ -15,8 +15,9 @@ DESCRIPTION ----------- Runs a number of housekeeping tasks within the current repository, such as compressing file revisions (to reduce disk space and increase -performance) and removing unreachable objects which may have been -created from prior invocations of 'git add'. +performance), removing unreachable objects which may have been +created from prior invocations of 'git add', packing refs, pruning +reflog, rerere metadata or stale working trees. Users are encouraged to run this task on a regular basis within each repository to maintain good disk space utilization and good @@ -45,20 +46,25 @@ OPTIONS With this option, 'git gc' checks whether any housekeeping is required; if not, it exits without performing any work. Some git commands run `git gc --auto` after performing - operations that could create many loose objects. + operations that could create many loose objects. Housekeeping + is required if there are too many loose objects or too many + packs in the repository. + -Housekeeping is required if there are too many loose objects or -too many packs in the repository. If the number of loose objects -exceeds the value of the `gc.auto` configuration variable, then -all loose objects are combined into a single pack using -`git repack -d -l`. Setting the value of `gc.auto` to 0 -disables automatic packing of loose objects. +If the number of loose objects exceeds the value of the `gc.auto` +configuration variable, then all loose objects are combined into a +single pack using `git repack -d -l`. Setting the value of `gc.auto` +to 0 disables automatic packing of loose objects. + If the number of packs exceeds the value of `gc.autoPackLimit`, then existing packs (except those marked with a `.keep` file) are consolidated into a single pack by using the `-A` option of 'git repack'. Setting `gc.autoPackLimit` to 0 disables automatic consolidation of packs. ++ +If houskeeping is required due to many loose objects or packs, all +other housekeeping tasks (e.g. rerere, working trees, reflog...) will +be performed as well. + --prune=<date>:: Prune loose objects older than date (default is 2 weeks ago, @@ -123,7 +129,7 @@ The optional configuration variable `gc.aggressiveWindow` controls how much time is spent optimizing the delta compression of the objects in the repository when the --aggressive option is specified. The larger the value, the more time is spent optimizing the delta compression. See -the documentation for the --window' option in linkgit:git-repack[1] for +the documentation for the --window option in linkgit:git-repack[1] for more details. This defaults to 250. Similarly, the optional configuration variable `gc.aggressiveDepth` @@ -133,6 +139,10 @@ The optional configuration variable `gc.pruneExpire` controls how old the unreferenced loose objects have to be before they are pruned. The default is "2 weeks ago". +Optional configuration variable `gc.worktreePruneExpire` controls how +old a stale working tree should be before `git worktree prune` deletes +it. Default is "3 months ago". + Notes ----- diff --git a/Documentation/git-log.txt b/Documentation/git-log.txt index 5437f8b..90761f1 100644 --- a/Documentation/git-log.txt +++ b/Documentation/git-log.txt @@ -9,7 +9,7 @@ git-log - Show commit logs SYNOPSIS -------- [verse] -'git log' [<options>] [<revision range>] [[\--] <path>...] +'git log' [<options>] [<revision range>] [[--] <path>...] DESCRIPTION ----------- @@ -90,13 +90,13 @@ include::line-range-format.txt[] ways to spell <revision range>, see the 'Specifying Ranges' section of linkgit:gitrevisions[7]. -[\--] <path>...:: +[--] <path>...:: Show only commits that are enough to explain how the files that match the specified paths came to be. See 'History Simplification' below for details and other simplification modes. + -Paths may need to be prefixed with ``\-- '' to separate them from +Paths may need to be prefixed with `--` to separate them from options or the revision range, when confusion arises. include::rev-list-options.txt[] @@ -125,7 +125,7 @@ EXAMPLES `git log --since="2 weeks ago" -- gitk`:: Show the changes during the last two weeks to the file 'gitk'. - The ``--'' is necessary to avoid confusion with the *branch* named + The `--` is necessary to avoid confusion with the *branch* named 'gitk' `git log --name-status release..test`:: diff --git a/Documentation/git-mktree.txt b/Documentation/git-mktree.txt index c3616e7..27fe2b3 100644 --- a/Documentation/git-mktree.txt +++ b/Documentation/git-mktree.txt @@ -14,7 +14,7 @@ SYNOPSIS DESCRIPTION ----------- Reads standard input in non-recursive `ls-tree` output format, and creates -a tree object. The order of the tree entries is normalised by mktree so +a tree object. The order of the tree entries is normalized by mktree so pre-sorting the input is not required. The object name of the tree object built is written to the standard output. diff --git a/Documentation/git-push.txt b/Documentation/git-push.txt index 5b08302..34410f9 100644 --- a/Documentation/git-push.txt +++ b/Documentation/git-push.txt @@ -300,7 +300,7 @@ origin +master` to force a push to the `master` branch). See the These options are passed to linkgit:git-send-pack[1]. A thin transfer significantly reduces the amount of sent data when the sender and receiver share many of the same objects in common. The default is - \--thin. + `--thin`. -q:: --quiet:: diff --git a/Documentation/git-rebase.txt b/Documentation/git-rebase.txt index 3277ca1..dd85206 100644 --- a/Documentation/git-rebase.txt +++ b/Documentation/git-rebase.txt @@ -364,9 +364,10 @@ default is `--no-fork-point`, otherwise the default is `--fork-point`. Incompatible with the --interactive option. --signoff:: - This flag is passed to 'git am' to sign off all the rebased - commits (see linkgit:git-am[1]). Incompatible with the - --interactive option. + Add a Signed-off-by: trailer to all the rebased commits. Note + that if `--interactive` is given then only commits marked to be + picked, edited or reworded will have the trailer added. Incompatible + with the `--preserve-merges` option. -i:: --interactive:: diff --git a/Documentation/git-send-email.txt b/Documentation/git-send-email.txt index 71ef97b..60cf96f 100644 --- a/Documentation/git-send-email.txt +++ b/Documentation/git-send-email.txt @@ -255,7 +255,7 @@ must be used for each option. --batch-size=<num>:: Some email servers (e.g. smtp.163.com) limit the number emails to be - sent per session (connection) and this will lead to a faliure when + sent per session (connection) and this will lead to a failure when sending many messages. With this option, send-email will disconnect after sending $<num> messages and wait for a few seconds (see --relogin-delay) and reconnect, to work around such a limit. You may want to @@ -473,16 +473,7 @@ edit ~/.gitconfig to specify your account settings: If you have multifactor authentication setup on your gmail account, you will need to generate an app-specific password for use with 'git send-email'. Visit -https://security.google.com/settings/security/apppasswords to setup an -app-specific password. Once setup, you can store it with the credentials -helper: - - $ git credential fill - protocol=smtp - host=smtp.gmail.com - username=youname@gmail.com - password=app-password - +https://security.google.com/settings/security/apppasswords to create it. Once your commits are ready to be sent to the mailing list, run the following commands: @@ -491,6 +482,11 @@ following commands: $ edit outgoing/0000-* $ git send-email outgoing/* +The first time you run it, you will be prompted for your credentials. Enter the +app-specific or your regular password as appropriate. If you have credential +helper configured (see linkgit:git-credential[1]), the password will be saved in +the credential store so you won't have to type it the next time. + Note: the following perl modules are required Net::SMTP::SSL, MIME::Base64 and Authen::SASL diff --git a/Documentation/git-shortlog.txt b/Documentation/git-shortlog.txt index ee6c547..bc80905 100644 --- a/Documentation/git-shortlog.txt +++ b/Documentation/git-shortlog.txt @@ -8,8 +8,8 @@ git-shortlog - Summarize 'git log' output SYNOPSIS -------- [verse] +'git shortlog' [<options>] [<revision range>] [[--] <path>...] git log --pretty=short | 'git shortlog' [<options>] -'git shortlog' [<options>] [<revision range>] [[\--] <path>...] DESCRIPTION ----------- @@ -69,11 +69,11 @@ them. ways to spell <revision range>, see the "Specifying Ranges" section of linkgit:gitrevisions[7]. -[\--] <path>...:: +[--] <path>...:: Consider only commits that are enough to explain how the files that match the specified paths came to be. + -Paths may need to be prefixed with "\-- " to separate them from +Paths may need to be prefixed with `--` to separate them from options or the revision range, when confusion arises. MAPPING AUTHORS diff --git a/Documentation/git-status.txt b/Documentation/git-status.txt index 6c230c0..c16e27e 100644 --- a/Documentation/git-status.txt +++ b/Documentation/git-status.txt @@ -113,7 +113,7 @@ The possible options are: - 'matching' - Shows ignored files and directories matching an ignore pattern. + -When 'matching' mode is specified, paths that explicity match an +When 'matching' mode is specified, paths that explicitly match an ignored pattern are shown. If a directory matches an ignore pattern, then it is shown, but not paths contained in the ignored directory. If a directory does not match an ignore pattern, but all contents are diff --git a/Documentation/git-submodule.txt b/Documentation/git-submodule.txt index 71c5618..630999f 100644 --- a/Documentation/git-submodule.txt +++ b/Documentation/git-submodule.txt @@ -213,8 +213,8 @@ sync [--recursive] [--] [<path>...]:: submodule URLs change upstream and you need to update your local repositories accordingly. + -"git submodule sync" synchronizes all submodules while -"git submodule sync \-- A" synchronizes submodule "A" only. +`git submodule sync` synchronizes all submodules while +`git submodule sync -- A` synchronizes submodule "A" only. + If `--recursive` is specified, this command will recurse into the registered submodules, and sync any nested submodules within. diff --git a/Documentation/git-svn.txt b/Documentation/git-svn.txt index 636e090..d59379e 100644 --- a/Documentation/git-svn.txt +++ b/Documentation/git-svn.txt @@ -635,7 +635,8 @@ config key: svn.findcopiesharder -A<filename>:: --authors-file=<filename>:: - Syntax is compatible with the file used by 'git cvsimport': + Syntax is compatible with the file used by 'git cvsimport' but + an empty email address can be supplied with '<>': + ------------------------------------------------------------------------ loginname = Joe User <user@example.com> @@ -654,8 +655,14 @@ config key: svn.authorsfile If this option is specified, for each SVN committer name that does not exist in the authors file, the given file is executed with the committer name as the first argument. The program is - expected to return a single line of the form "Name <email>", - which will be treated as if included in the authors file. + expected to return a single line of the form "Name <email>" or + "Name <>", which will be treated as if included in the authors + file. ++ +Due to historical reasons a relative 'filename' is first searched +relative to the current directory for 'init' and 'clone' and relative +to the root of the working tree for 'fetch'. If 'filename' is +not found, it is searched like any other command in '$PATH'. + [verse] config key: svn.authorsProg diff --git a/Documentation/git-worktree.txt b/Documentation/git-worktree.txt index e7eb24a..9920d9c 100644 --- a/Documentation/git-worktree.txt +++ b/Documentation/git-worktree.txt @@ -14,7 +14,7 @@ SYNOPSIS 'git worktree lock' [--reason <string>] <worktree> 'git worktree move' <worktree> <new-path> 'git worktree prune' [-n] [-v] [--expire <expire>] -'git worktree remove' [--force] <worktree> +'git worktree remove' [-f] <worktree> 'git worktree unlock' <worktree> DESCRIPTION @@ -27,11 +27,12 @@ out more than one branch at a time. With `git worktree add` a new working tree is associated with the repository. This new working tree is called a "linked working tree" as opposed to the "main working tree" prepared by "git init" or "git clone". A repository has one main working tree (if it's not a -bare repository) and zero or more linked working trees. +bare repository) and zero or more linked working trees. When you are done +with a linked working tree, remove it with `git worktree remove`. -When you are done with a linked working tree you can simply delete it. -The working tree's administrative files in the repository (see -"DETAILS" below) will eventually be removed automatically (see +If a working tree is deleted without using `git worktree remove`, then +its associated administrative files, which reside in the repository +(see "DETAILS" below), will eventually be removed automatically (see `gc.worktreePruneExpire` in linkgit:git-config[1]), or you can run `git worktree prune` in the main or any linked working tree to clean up any stale administrative files. @@ -106,7 +107,7 @@ OPTIONS By default, `add` refuses to create a new working tree when `<commit-ish>` is a branch name and is already checked out by another working tree and `remove` refuses to remove an unclean - working tree. This option overrides that safeguard. + working tree. This option overrides these safeguards. -b <new-branch>:: -B <new-branch>:: @@ -232,7 +233,7 @@ The worktree list command has two output formats. The default format shows the details on a single line with columns. For example: ------------ -S git worktree list +$ git worktree list /path/to/bare-source (bare) /path/to/linked-worktree abcd1234 [master] /path/to/other-linked-worktree 1234abc (detached HEAD) @@ -247,7 +248,7 @@ if the value is true. An empty line indicates the end of a worktree. For example: ------------ -S git worktree list --porcelain +$ git worktree list --porcelain worktree /path/to/bare-source bare @@ -278,8 +279,7 @@ $ pushd ../temp # ... hack hack hack ... $ git commit -a -m 'emergency fix for boss' $ popd -$ rm -rf ../temp -$ git worktree prune +$ git worktree remove ../temp ------------ BUGS diff --git a/Documentation/gitattributes.txt b/Documentation/gitattributes.txt index 1094fe2..ee210be 100644 --- a/Documentation/gitattributes.txt +++ b/Documentation/gitattributes.txt @@ -279,6 +279,94 @@ few exceptions. Even though... catch potential problems early, safety triggers. +`working-tree-encoding` +^^^^^^^^^^^^^^^^^^^^^^^ + +Git recognizes files encoded in ASCII or one of its supersets (e.g. +UTF-8, ISO-8859-1, ...) as text files. Files encoded in certain other +encodings (e.g. UTF-16) are interpreted as binary and consequently +built-in Git text processing tools (e.g. 'git diff') as well as most Git +web front ends do not visualize the contents of these files by default. + +In these cases you can tell Git the encoding of a file in the working +directory with the `working-tree-encoding` attribute. If a file with this +attribute is added to Git, then Git reencodes the content from the +specified encoding to UTF-8. Finally, Git stores the UTF-8 encoded +content in its internal data structure (called "the index"). On checkout +the content is reencoded back to the specified encoding. + +Please note that using the `working-tree-encoding` attribute may have a +number of pitfalls: + +- Alternative Git implementations (e.g. JGit or libgit2) and older Git + versions (as of March 2018) do not support the `working-tree-encoding` + attribute. If you decide to use the `working-tree-encoding` attribute + in your repository, then it is strongly recommended to ensure that all + clients working with the repository support it. + + For example, Microsoft Visual Studio resources files (`*.rc`) or + PowerShell script files (`*.ps1`) are sometimes encoded in UTF-16. + If you declare `*.ps1` as files as UTF-16 and you add `foo.ps1` with + a `working-tree-encoding` enabled Git client, then `foo.ps1` will be + stored as UTF-8 internally. A client without `working-tree-encoding` + support will checkout `foo.ps1` as UTF-8 encoded file. This will + typically cause trouble for the users of this file. + + If a Git client, that does not support the `working-tree-encoding` + attribute, adds a new file `bar.ps1`, then `bar.ps1` will be + stored "as-is" internally (in this example probably as UTF-16). + A client with `working-tree-encoding` support will interpret the + internal contents as UTF-8 and try to convert it to UTF-16 on checkout. + That operation will fail and cause an error. + +- Reencoding content to non-UTF encodings can cause errors as the + conversion might not be UTF-8 round trip safe. If you suspect your + encoding to not be round trip safe, then add it to + `core.checkRoundtripEncoding` to make Git check the round trip + encoding (see linkgit:git-config[1]). SHIFT-JIS (Japanese character + set) is known to have round trip issues with UTF-8 and is checked by + default. + +- Reencoding content requires resources that might slow down certain + Git operations (e.g 'git checkout' or 'git add'). + +Use the `working-tree-encoding` attribute only if you cannot store a file +in UTF-8 encoding and if you want Git to be able to process the content +as text. + +As an example, use the following attributes if your '*.ps1' files are +UTF-16 encoded with byte order mark (BOM) and you want Git to perform +automatic line ending conversion based on your platform. + +------------------------ +*.ps1 text working-tree-encoding=UTF-16 +------------------------ + +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. Please note, it is highly recommended to +explicitly define the line endings with `eol` if the `working-tree-encoding` +attribute is used to avoid ambiguity. + +------------------------ +*.ps1 text working-tree-encoding=UTF-16LE eol=CRLF +------------------------ + +You can get a list of all available encodings on your platform with the +following command: + +------------------------ +iconv --list +------------------------ + +If you do not know the encoding of a file, then you can use the `file` +command to guess the encoding: + +------------------------ +file foo.ps1 +------------------------ + + `ident` ^^^^^^^ diff --git a/Documentation/gitk.txt b/Documentation/gitk.txt index ca96c28..244cd01 100644 --- a/Documentation/gitk.txt +++ b/Documentation/gitk.txt @@ -8,7 +8,7 @@ gitk - The Git repository browser SYNOPSIS -------- [verse] -'gitk' [<options>] [<revision range>] [\--] [<path>...] +'gitk' [<options>] [<revision range>] [--] [<path>...] DESCRIPTION ----------- diff --git a/Documentation/gitremote-helpers.txt b/Documentation/gitremote-helpers.txt index 4b8c93e..9d1459a 100644 --- a/Documentation/gitremote-helpers.txt +++ b/Documentation/gitremote-helpers.txt @@ -102,6 +102,14 @@ Capabilities for Pushing + Supported commands: 'connect'. +'stateless-connect':: + Experimental; for internal use only. + Can attempt to connect to a remote server for communication + using git's wire-protocol version 2. See the documentation + for the stateless-connect command for more information. ++ +Supported commands: 'stateless-connect'. + 'push':: Can discover remote refs and push local commits and the history leading up to them to new or existing remote refs. @@ -136,6 +144,14 @@ Capabilities for Fetching + Supported commands: 'connect'. +'stateless-connect':: + Experimental; for internal use only. + Can attempt to connect to a remote server for communication + using git's wire-protocol version 2. See the documentation + for the stateless-connect command for more information. ++ +Supported commands: 'stateless-connect'. + 'fetch':: Can discover remote refs and transfer objects reachable from them to the local object store. @@ -375,6 +391,22 @@ Supported if the helper has the "export" capability. + Supported if the helper has the "connect" capability. +'stateless-connect' <service>:: + Experimental; for internal use only. + Connects to the given remote service for communication using + git's wire-protocol version 2. Valid replies to this command + are empty line (connection established), 'fallback' (no smart + transport support, fall back to dumb transports) and just + exiting with error message printed (can't connect, don't bother + trying to fall back). After line feed terminating the positive + (empty) response, the output of the service starts. Messages + (both request and response) must consist of zero or more + PKT-LINEs, terminating in a flush packet. The client must not + expect the server to store any state in between request-response + pairs. After the connection ends, the remote helper exits. ++ +Supported if the helper has the "stateless-connect" capability. + If a fatal error occurs, the program writes the error message to stderr and exits. The caller should expect that a suitable error message has been printed if the child closes the connection without diff --git a/Documentation/gitrepository-layout.txt b/Documentation/gitrepository-layout.txt index c60bcad..e85148f 100644 --- a/Documentation/gitrepository-layout.txt +++ b/Documentation/gitrepository-layout.txt @@ -275,11 +275,6 @@ worktrees/<id>/locked:: or manually by `git worktree prune`. The file may contain a string explaining why the repository is locked. -worktrees/<id>/link:: - If this file exists, it is a hard link to the linked .git - file. It is used to detect if the linked repository is - manually removed. - SEE ALSO -------- linkgit:git-init[1], diff --git a/Documentation/glossary-content.txt b/Documentation/glossary-content.txt index 6b8888d..6c2d23d 100644 --- a/Documentation/glossary-content.txt +++ b/Documentation/glossary-content.txt @@ -463,7 +463,7 @@ exclude;; [[def_push]]push:: Pushing a <<def_branch,branch>> means to get the branch's <<def_head_ref,head ref>> from a remote <<def_repository,repository>>, - find out if it is a direct ancestor to the branch's local + find out if it is an ancestor to the branch's local head ref, and in that case, putting all objects, which are <<def_reachable,reachable>> from the local head ref, and which are missing from the remote diff --git a/Documentation/howto/recover-corrupted-object-harder.txt b/Documentation/howto/recover-corrupted-object-harder.txt index 9c4cd09..8994e25 100644 --- a/Documentation/howto/recover-corrupted-object-harder.txt +++ b/Documentation/howto/recover-corrupted-object-harder.txt @@ -80,7 +80,7 @@ valid pack like: # now add our object data cat object >>tmp.pack # and then append the pack trailer - /path/to/git.git/test-sha1 -b <tmp.pack >trailer + /path/to/git.git/t/helper/test-tool sha1 -b <tmp.pack >trailer cat trailer >>tmp.pack ------------ diff --git a/Documentation/technical/api-directory-listing.txt b/Documentation/technical/api-directory-listing.txt index 7fae00f..4f44ca2 100644 --- a/Documentation/technical/api-directory-listing.txt +++ b/Documentation/technical/api-directory-listing.txt @@ -53,7 +53,7 @@ The notable options are: not be returned even if all of its contents are ignored. In this case, the contents are returned as individual entries. + -If this is set, files and directories that explicity match an ignore +If this is set, files and directories that explicitly match an ignore pattern are reported. Implicity ignored directories (directories that do not match an ignore pattern, but whose contents are all ignored) are not reported, instead all of the contents are reported. diff --git a/Documentation/technical/api-object-access.txt b/Documentation/technical/api-object-access.txt index a1162e5..5b29622 100644 --- a/Documentation/technical/api-object-access.txt +++ b/Documentation/technical/api-object-access.txt @@ -1,7 +1,7 @@ object access API ================= -Talk about <sha1_file.c> and <object.h> family, things like +Talk about <sha1-file.c> and <object.h> family, things like * read_sha1_file() * read_object_with_reference() diff --git a/Documentation/technical/api-submodule-config.txt b/Documentation/technical/api-submodule-config.txt index ee907c4..fb06089 100644 --- a/Documentation/technical/api-submodule-config.txt +++ b/Documentation/technical/api-submodule-config.txt @@ -38,7 +38,7 @@ Data Structures Functions --------- -`void submodule_free()`:: +`void submodule_free(struct repository *r)`:: Use these to free the internally cached values. diff --git a/Documentation/technical/commit-graph-format.txt b/Documentation/technical/commit-graph-format.txt new file mode 100644 index 0000000..ad6af81 --- /dev/null +++ b/Documentation/technical/commit-graph-format.txt @@ -0,0 +1,97 @@ +Git commit graph format +======================= + +The Git commit graph stores a list of commit OIDs and some associated +metadata, including: + +- The generation number of the commit. Commits with no parents have + generation number 1; commits with parents have generation number + one more than the maximum generation number of its parents. We + reserve zero as special, and can be used to mark a generation + number invalid or as "not computed". + +- The root tree OID. + +- The commit date. + +- The parents of the commit, stored using positional references within + the graph file. + +These positional references are stored as unsigned 32-bit integers +corresponding to the array position withing the list of commit OIDs. We +use the most-significant bit for special purposes, so we can store at most +(1 << 31) - 1 (around 2 billion) commits. + +== Commit graph files have the following format: + +In order to allow extensions that add extra data to the graph, we organize +the body into "chunks" and provide a binary lookup table at the beginning +of the body. The header includes certain values, such as number of chunks +and hash type. + +All 4-byte numbers are in network order. + +HEADER: + + 4-byte signature: + The signature is: {'C', 'G', 'P', 'H'} + + 1-byte version number: + Currently, the only valid version is 1. + + 1-byte Hash Version (1 = SHA-1) + We infer the hash length (H) from this value. + + 1-byte number (C) of "chunks" + + 1-byte (reserved for later use) + Current clients should ignore this value. + +CHUNK LOOKUP: + + (C + 1) * 12 bytes listing the table of contents for the chunks: + First 4 bytes describe the chunk id. Value 0 is a terminating label. + Other 8 bytes provide the byte-offset in current file for chunk to + start. (Chunks are ordered contiguously in the file, so you can infer + the length using the next chunk position if necessary.) Each chunk + ID appears at most once. + + The remaining data in the body is described one chunk at a time, and + these chunks may be given in any order. Chunks are required unless + otherwise specified. + +CHUNK DATA: + + OID Fanout (ID: {'O', 'I', 'D', 'F'}) (256 * 4 bytes) + The ith entry, F[i], stores the number of OIDs with first + byte at most i. Thus F[255] stores the total + number of commits (N). + + OID Lookup (ID: {'O', 'I', 'D', 'L'}) (N * H bytes) + The OIDs for all commits in the graph, sorted in ascending order. + + Commit Data (ID: {'C', 'G', 'E', 'T' }) (N * (H + 16) bytes) + * The first H bytes are for the OID of the root tree. + * The next 8 bytes are for the positions of the first two parents + of the ith commit. Stores value 0xffffffff if no parent in that + position. If there are more than two parents, the second value + has its most-significant bit on and the other bits store an array + position into the Large Edge List chunk. + * The next 8 bytes store the generation number of the commit and + the commit time in seconds since EPOCH. The generation number + uses the higher 30 bits of the first 4 bytes, while the commit + time uses the 32 bits of the second 4 bytes, along with the lowest + 2 bits of the lowest byte, storing the 33rd and 34th bit of the + commit time. + + Large Edge List (ID: {'E', 'D', 'G', 'E'}) [Optional] + This list of 4-byte values store the second through nth parents for + all octopus merges. The second parent value in the commit data stores + an array position within this list along with the most-significant bit + on. Starting at that array position, iterate through this list of commit + positions for the parents until reaching a value with the most-significant + bit on. The other bits correspond to the position of the last parent. + +TRAILER: + + H-byte HASH-checksum of all of the above. diff --git a/Documentation/technical/commit-graph.txt b/Documentation/technical/commit-graph.txt new file mode 100644 index 0000000..0550c6d --- /dev/null +++ b/Documentation/technical/commit-graph.txt @@ -0,0 +1,163 @@ +Git Commit Graph Design Notes +============================= + +Git walks the commit graph for many reasons, including: + +1. Listing and filtering commit history. +2. Computing merge bases. + +These operations can become slow as the commit count grows. The merge +base calculation shows up in many user-facing commands, such as 'merge-base' +or 'status' and can take minutes to compute depending on history shape. + +There are two main costs here: + +1. Decompressing and parsing commits. +2. Walking the entire graph to satisfy topological order constraints. + +The commit graph file is a supplemental data structure that accelerates +commit graph walks. If a user downgrades or disables the 'core.commitGraph' +config setting, then the existing ODB is sufficient. The file is stored +as "commit-graph" either in the .git/objects/info directory or in the info +directory of an alternate. + +The commit graph file stores the commit graph structure along with some +extra metadata to speed up graph walks. By listing commit OIDs in lexi- +cographic order, we can identify an integer position for each commit and +refer to the parents of a commit using those integer positions. We use +binary search to find initial commits and then use the integer positions +for fast lookups during the walk. + +A consumer may load the following info for a commit from the graph: + +1. The commit OID. +2. The list of parents, along with their integer position. +3. The commit date. +4. The root tree OID. +5. The generation number (see definition below). + +Values 1-4 satisfy the requirements of parse_commit_gently(). + +Define the "generation number" of a commit recursively as follows: + + * A commit with no parents (a root commit) has generation number one. + + * A commit with at least one parent has generation number one more than + the largest generation number among its parents. + +Equivalently, the generation number of a commit A is one more than the +length of a longest path from A to a root commit. The recursive definition +is easier to use for computation and observing the following property: + + If A and B are commits with generation numbers N and M, respectively, + and N <= M, then A cannot reach B. That is, we know without searching + that B is not an ancestor of A because it is further from a root commit + than A. + + Conversely, when checking if A is an ancestor of B, then we only need + to walk commits until all commits on the walk boundary have generation + number at most N. If we walk commits using a priority queue seeded by + generation numbers, then we always expand the boundary commit with highest + generation number and can easily detect the stopping condition. + +This property can be used to significantly reduce the time it takes to +walk commits and determine topological relationships. Without generation +numbers, the general heuristic is the following: + + If A and B are commits with commit time X and Y, respectively, and + X < Y, then A _probably_ cannot reach B. + +This heuristic is currently used whenever the computation is allowed to +violate topological relationships due to clock skew (such as "git log" +with default order), but is not used when the topological order is +required (such as merge base calculations, "git log --graph"). + +In practice, we expect some commits to be created recently and not stored +in the commit graph. We can treat these commits as having "infinite" +generation number and walk until reaching commits with known generation +number. + +Design Details +-------------- + +- The commit graph file is stored in a file named 'commit-graph' in the + .git/objects/info directory. This could be stored in the info directory + of an alternate. + +- The core.commitGraph config setting must be on to consume graph files. + +- The file format includes parameters for the object ID hash function, + so a future change of hash algorithm does not require a change in format. + +Future Work +----------- + +- The commit graph feature currently does not honor commit grafts. This can + be remedied by duplicating or refactoring the current graft logic. + +- The 'commit-graph' subcommand does not have a "verify" mode that is + necessary for integration with fsck. + +- The file format includes room for precomputed generation numbers. These + are not currently computed, so all generation numbers will be marked as + 0 (or "uncomputed"). A later patch will include this calculation. + +- After computing and storing generation numbers, we must make graph + walks aware of generation numbers to gain the performance benefits they + enable. This will mostly be accomplished by swapping a commit-date-ordered + priority queue with one ordered by generation number. The following + operations are important candidates: + + - paint_down_to_common() + - 'log --topo-order' + +- Currently, parse_commit_gently() requires filling in the root tree + object for a commit. This passes through lookup_tree() and consequently + lookup_object(). Also, it calls lookup_commit() when loading the parents. + These method calls check the ODB for object existence, even if the + consumer does not need the content. For example, we do not need the + tree contents when computing merge bases. Now that commit parsing is + removed from the computation time, these lookup operations are the + slowest operations keeping graph walks from being fast. Consider + loading these objects without verifying their existence in the ODB and + only loading them fully when consumers need them. Consider a method + such as "ensure_tree_loaded(commit)" that fully loads a tree before + using commit->tree. + +- The current design uses the 'commit-graph' subcommand to generate the graph. + When this feature stabilizes enough to recommend to most users, we should + add automatic graph writes to common operations that create many commits. + For example, one could compute a graph on 'clone', 'fetch', or 'repack' + commands. + +- A server could provide a commit graph file as part of the network protocol + to avoid extra calculations by clients. This feature is only of benefit if + the user is willing to trust the file, because verifying the file is correct + is as hard as computing it from scratch. + +Related Links +------------- +[0] https://bugs.chromium.org/p/git/issues/detail?id=8 + Chromium work item for: Serialized Commit Graph + +[1] https://public-inbox.org/git/20110713070517.GC18566@sigill.intra.peff.net/ + An abandoned patch that introduced generation numbers. + +[2] https://public-inbox.org/git/20170908033403.q7e6dj7benasrjes@sigill.intra.peff.net/ + Discussion about generation numbers on commits and how they interact + with fsck. + +[3] https://public-inbox.org/git/20170908034739.4op3w4f2ma5s65ku@sigill.intra.peff.net/ + More discussion about generation numbers and not storing them inside + commit objects. A valuable quote: + + "I think we should be moving more in the direction of keeping + repo-local caches for optimizations. Reachability bitmaps have been + a big performance win. I think we should be doing the same with our + properties of commits. Not just generation numbers, but making it + cheap to access the graph structure without zlib-inflating whole + commit objects (i.e., packv4 or something like the "metapacks" I + proposed a few years ago)." + +[4] https://public-inbox.org/git/20180108154822.54829-1-git@jeffhostetler.com/T/#u + A patch to remove the ahead-behind calculation from 'status'. diff --git a/Documentation/technical/hash-function-transition.txt b/Documentation/technical/hash-function-transition.txt index 417ba49..4ab6cd1 100644 --- a/Documentation/technical/hash-function-transition.txt +++ b/Documentation/technical/hash-function-transition.txt @@ -28,11 +28,30 @@ advantages: address stored content. Over time some flaws in SHA-1 have been discovered by security -researchers. https://shattered.io demonstrated a practical SHA-1 hash -collision. As a result, SHA-1 cannot be considered cryptographically -secure any more. This impacts the communication of hash values because -we cannot trust that a given hash value represents the known good -version of content that the speaker intended. +researchers. On 23 February 2017 the SHAttered attack +(https://shattered.io) demonstrated a practical SHA-1 hash collision. + +Git v2.13.0 and later subsequently moved to a hardened SHA-1 +implementation by default, which isn't vulnerable to the SHAttered +attack. + +Thus Git has in effect already migrated to a new hash that isn't SHA-1 +and doesn't share its vulnerabilities, its new hash function just +happens to produce exactly the same output for all known inputs, +except two PDFs published by the SHAttered researchers, and the new +implementation (written by those researchers) claims to detect future +cryptanalytic collision attacks. + +Regardless, it's considered prudent to move past any variant of SHA-1 +to a new hash. There's no guarantee that future attacks on SHA-1 won't +be published in the future, and those attacks may not have viable +mitigations. + +If SHA-1 and its variants were to be truly broken, Git's hash function +could not be considered cryptographically secure any more. This would +impact the communication of hash values because we could not trust +that a given hash value represented the known good version of content +that the speaker intended. SHA-1 still possesses the other properties such as fast object lookup and safe error checking, but other hash functions are equally suitable @@ -116,10 +135,15 @@ Documentation/technical/repository-version.txt) with extensions objectFormat = newhash compatObjectFormat = sha1 -Specifying a repository format extension ensures that versions of Git -not aware of NewHash do not try to operate on these repositories, -instead producing an error message: +The combination of setting `core.repositoryFormatVersion=1` and +populating `extensions.*` ensures that all versions of Git later than +`v0.99.9l` will die instead of trying to operate on the NewHash +repository, instead producing an error message. + # Between v0.99.9l and v2.7.0 + $ git status + fatal: Expected git repo version <= 0, found 1 + # After v2.7.0 $ git status fatal: unknown repository extensions found: objectformat diff --git a/Documentation/technical/protocol-v2.txt b/Documentation/technical/protocol-v2.txt new file mode 100644 index 0000000..136179d --- /dev/null +++ b/Documentation/technical/protocol-v2.txt @@ -0,0 +1,395 @@ + Git Wire Protocol, Version 2 +============================== + +This document presents a specification for a version 2 of Git's wire +protocol. Protocol v2 will improve upon v1 in the following ways: + + * Instead of multiple service names, multiple commands will be + supported by a single service + * Easily extendable as capabilities are moved into their own section + of the protocol, no longer being hidden behind a NUL byte and + limited by the size of a pkt-line + * Separate out other information hidden behind NUL bytes (e.g. agent + string as a capability and symrefs can be requested using 'ls-refs') + * Reference advertisement will be omitted unless explicitly requested + * ls-refs command to explicitly request some refs + * Designed with http and stateless-rpc in mind. With clear flush + semantics the http remote helper can simply act as a proxy + +In protocol v2 communication is command oriented. When first contacting a +server a list of capabilities will advertised. Some of these capabilities +will be commands which a client can request be executed. Once a command +has completed, a client can reuse the connection and request that other +commands be executed. + + Packet-Line Framing +--------------------- + +All communication is done using packet-line framing, just as in v1. See +`Documentation/technical/pack-protocol.txt` and +`Documentation/technical/protocol-common.txt` for more information. + +In protocol v2 these special packets will have the following semantics: + + * '0000' Flush Packet (flush-pkt) - indicates the end of a message + * '0001' Delimiter Packet (delim-pkt) - separates sections of a message + + Initial Client Request +------------------------ + +In general a client can request to speak protocol v2 by sending +`version=2` through the respective side-channel for the transport being +used which inevitably sets `GIT_PROTOCOL`. More information can be +found in `pack-protocol.txt` and `http-protocol.txt`. In all cases the +response from the server is the capability advertisement. + + Git Transport +~~~~~~~~~~~~~~~ + +When using the git:// transport, you can request to use protocol v2 by +sending "version=2" as an extra parameter: + + 003egit-upload-pack /project.git\0host=myserver.com\0\0version=2\0 + + SSH and File Transport +~~~~~~~~~~~~~~~~~~~~~~~~ + +When using either the ssh:// or file:// transport, the GIT_PROTOCOL +environment variable must be set explicitly to include "version=2". + + HTTP Transport +~~~~~~~~~~~~~~~~ + +When using the http:// or https:// transport a client makes a "smart" +info/refs request as described in `http-protocol.txt` and requests that +v2 be used by supplying "version=2" in the `Git-Protocol` header. + + C: Git-Protocol: version=2 + C: + C: GET $GIT_URL/info/refs?service=git-upload-pack HTTP/1.0 + +A v2 server would reply: + + S: 200 OK + S: <Some headers> + S: ... + S: + S: 000eversion 2\n + S: <capability-advertisement> + +Subsequent requests are then made directly to the service +`$GIT_URL/git-upload-pack`. (This works the same for git-receive-pack). + + Capability Advertisement +-------------------------- + +A server which decides to communicate (based on a request from a client) +using protocol version 2, notifies the client by sending a version string +in its initial response followed by an advertisement of its capabilities. +Each capability is a key with an optional value. Clients must ignore all +unknown keys. Semantics of unknown values are left to the definition of +each key. Some capabilities will describe commands which can be requested +to be executed by the client. + + capability-advertisement = protocol-version + capability-list + flush-pkt + + protocol-version = PKT-LINE("version 2" LF) + capability-list = *capability + capability = PKT-LINE(key[=value] LF) + + key = 1*(ALPHA | DIGIT | "-_") + value = 1*(ALPHA | DIGIT | " -_.,?\/{}[]()<>!@#$%^&*+=:;") + + Command Request +----------------- + +After receiving the capability advertisement, a client can then issue a +request to select the command it wants with any particular capabilities +or arguments. There is then an optional section where the client can +provide any command specific parameters or queries. Only a single +command can be requested at a time. + + request = empty-request | command-request + empty-request = flush-pkt + command-request = command + capability-list + [command-args] + flush-pkt + command = PKT-LINE("command=" key LF) + command-args = delim-pkt + *command-specific-arg + + command-specific-args are packet line framed arguments defined by + each individual command. + +The server will then check to ensure that the client's request is +comprised of a valid command as well as valid capabilities which were +advertised. If the request is valid the server will then execute the +command. A server MUST wait till it has received the client's entire +request before issuing a response. The format of the response is +determined by the command being executed, but in all cases a flush-pkt +indicates the end of the response. + +When a command has finished, and the client has received the entire +response from the server, a client can either request that another +command be executed or can terminate the connection. A client may +optionally send an empty request consisting of just a flush-pkt to +indicate that no more requests will be made. + + Capabilities +-------------- + +There are two different types of capabilities: normal capabilities, +which can be used to to convey information or alter the behavior of a +request, and commands, which are the core actions that a client wants to +perform (fetch, push, etc). + +Protocol version 2 is stateless by default. This means that all commands +must only last a single round and be stateless from the perspective of the +server side, unless the client has requested a capability indicating that +state should be maintained by the server. Clients MUST NOT require state +management on the server side in order to function correctly. This +permits simple round-robin load-balancing on the server side, without +needing to worry about state management. + + agent +~~~~~~~ + +The server can advertise the `agent` capability with a value `X` (in the +form `agent=X`) to notify the client that the server is running version +`X`. The client may optionally send its own agent string by including +the `agent` capability with a value `Y` (in the form `agent=Y`) in its +request to the server (but it MUST NOT do so if the server did not +advertise the agent capability). The `X` and `Y` strings may contain any +printable ASCII characters except space (i.e., the byte range 32 < x < +127), and are typically of the form "package/version" (e.g., +"git/1.8.3.1"). The 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. + + ls-refs +~~~~~~~~~ + +`ls-refs` is the command used to request a reference advertisement in v2. +Unlike the current reference advertisement, ls-refs takes in arguments +which can be used to limit the refs sent from the server. + +Additional features not supported in the base command will be advertised +as the value of the command in the capability advertisement in the form +of a space separated list of features: "<command>=<feature 1> <feature 2>" + +ls-refs takes in the following arguments: + + symrefs + In addition to the object pointed by it, show the underlying ref + pointed by it when showing a symbolic ref. + peel + Show peeled tags. + ref-prefix <prefix> + When specified, only references having a prefix matching one of + the provided prefixes are displayed. + +The output of ls-refs is as follows: + + output = *ref + flush-pkt + ref = PKT-LINE(obj-id SP refname *(SP ref-attribute) LF) + ref-attribute = (symref | peeled) + symref = "symref-target:" symref-target + peeled = "peeled:" obj-id + + fetch +~~~~~~~ + +`fetch` is the command used to fetch a packfile in v2. It can be looked +at as a modified version of the v1 fetch where the ref-advertisement is +stripped out (since the `ls-refs` command fills that role) and the +message format is tweaked to eliminate redundancies and permit easy +addition of future extensions. + +Additional features not supported in the base command will be advertised +as the value of the command in the capability advertisement in the form +of a space separated list of features: "<command>=<feature 1> <feature 2>" + +A `fetch` request can take the following arguments: + + want <oid> + Indicates to the server an object which the client wants to + retrieve. Wants can be anything and are not limited to + advertised objects. + + have <oid> + Indicates to the server an object which the client has locally. + This allows the server to make a packfile which only contains + the objects that the client needs. Multiple 'have' lines can be + supplied. + + done + Indicates to the server that negotiation should terminate (or + not even begin if performing a clone) and that the server should + use the information supplied in the request to construct the + packfile. + + thin-pack + Request that a thin pack be sent, which is a pack with deltas + which reference base objects not contained within the pack (but + are known to exist at the receiving end). This can reduce the + network traffic significantly, but it requires the receiving end + to know how to "thicken" these packs by adding the missing bases + to the pack. + + no-progress + Request that progress information that would normally be sent on + side-band channel 2, during the packfile transfer, should not be + sent. However, the side-band channel 3 is still used for error + responses. + + include-tag + Request that annotated tags should be sent if the objects they + point to are being sent. + + ofs-delta + Indicate that the client understands PACKv2 with delta referring + to its base by position in pack rather than by an oid. That is, + they can read OBJ_OFS_DELTA (ake type 6) in a packfile. + +If the 'shallow' feature is advertised the following arguments can be +included in the clients request as well as the potential addition of the +'shallow-info' section in the server's response as explained below. + + shallow <oid> + A client must notify the server of all commits for which it only + has shallow copies (meaning that it doesn't have the parents of + a commit) by supplying a 'shallow <oid>' line for each such + object so that the server is aware of the limitations of the + client's history. This is so that the server is aware that the + client may not have all objects reachable from such commits. + + deepen <depth> + Requests that the fetch/clone should be shallow having a commit + depth of <depth> relative to the remote side. + + deepen-relative + Requests that the semantics of the "deepen" command be changed + to indicate that the depth requested is relative to the client's + current shallow boundary, instead of relative to the requested + commits. + + deepen-since <timestamp> + Requests that the shallow clone/fetch should be cut at a + specific time, instead of depth. Internally it's equivalent to + doing "git rev-list --max-age=<timestamp>". Cannot be used with + "deepen". + + deepen-not <rev> + Requests that the shallow clone/fetch should be cut at a + specific revision specified by '<rev>', instead of a depth. + Internally it's equivalent of doing "git rev-list --not <rev>". + Cannot be used with "deepen", but can be used with + "deepen-since". + +The response of `fetch` is broken into a number of sections separated by +delimiter packets (0001), with each section beginning with its section +header. + + output = *section + section = (acknowledgments | shallow-info | packfile) + (flush-pkt | delim-pkt) + + acknowledgments = PKT-LINE("acknowledgments" LF) + (nak | *ack) + (ready) + ready = PKT-LINE("ready" LF) + nak = PKT-LINE("NAK" LF) + ack = PKT-LINE("ACK" SP obj-id LF) + + shallow-info = PKT-LINE("shallow-info" LF) + *PKT-LINE((shallow | unshallow) LF) + shallow = "shallow" SP obj-id + unshallow = "unshallow" SP obj-id + + packfile = PKT-LINE("packfile" LF) + *PKT-LINE(%x01-03 *%x00-ff) + + acknowledgments section + * If the client determines that it is finished with negotiations + by sending a "done" line, the acknowledgments sections MUST be + omitted from the server's response. + + * Always begins with the section header "acknowledgments" + + * The server will respond with "NAK" if none of the object ids sent + as have lines were common. + + * The server will respond with "ACK obj-id" for all of the + object ids sent as have lines which are common. + + * A response cannot have both "ACK" lines as well as a "NAK" + line. + + * The server will respond with a "ready" line indicating that + the server has found an acceptable common base and is ready to + make and send a packfile (which will be found in the packfile + section of the same response) + + * If the server has found a suitable cut point and has decided + to send a "ready" line, then the server can decide to (as an + optimization) omit any "ACK" lines it would have sent during + its response. This is because the server will have already + determined the objects it plans to send to the client and no + further negotiation is needed. + + shallow-info section + * If the client has requested a shallow fetch/clone, a shallow + client requests a fetch or the server is shallow then the + server's response may include a shallow-info section. The + shallow-info section will be included if (due to one of the + above conditions) the server needs to inform the client of any + shallow boundaries or adjustments to the clients already + existing shallow boundaries. + + * Always begins with the section header "shallow-info" + + * If a positive depth is requested, the server will compute the + set of commits which are no deeper than the desired depth. + + * The server sends a "shallow obj-id" line for each commit whose + parents will not be sent in the following packfile. + + * The server sends an "unshallow obj-id" line for each commit + which the client has indicated is shallow, but is no longer + shallow as a result of the fetch (due to its parents being + sent in the following packfile). + + * The server MUST NOT send any "unshallow" lines for anything + which the client has not indicated was shallow as a part of + its request. + + * This section is only included if a packfile section is also + included in the response. + + packfile section + * This section is only included if the client has sent 'want' + lines in its request and either requested that no more + negotiation be done by sending 'done' or if the server has + decided it has found a sufficient cut point to produce a + packfile. + + * Always begins with the section header "packfile" + + * The transmission of the packfile begins immediately after the + section header + + * The data transfer of the packfile is always multiplexed, using + the same semantics of the 'side-band-64k' capability from + protocol version 1. This means that each packet, during the + packfile data stream, is made up of a leading 4-byte pkt-line + length (typical of the pkt-line format), followed by a 1-byte + stream code, followed by the actual data. + + The stream code can be one of: + 1 - pack data + 2 - progress messages + 3 - fatal error message just before stream aborts |