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diff --git a/third_party/git/Documentation/git-update-index.txt b/third_party/git/Documentation/git-update-index.txt new file mode 100644 index 000000000000..1c4d146a41ce --- /dev/null +++ b/third_party/git/Documentation/git-update-index.txt @@ -0,0 +1,554 @@ +git-update-index(1) +=================== + +NAME +---- +git-update-index - Register file contents in the working tree to the index + + +SYNOPSIS +-------- +[verse] +'git update-index' + [--add] [--remove | --force-remove] [--replace] + [--refresh] [-q] [--unmerged] [--ignore-missing] + [(--cacheinfo <mode>,<object>,<file>)...] + [--chmod=(+|-)x] + [--[no-]assume-unchanged] + [--[no-]skip-worktree] + [--[no-]fsmonitor-valid] + [--ignore-submodules] + [--[no-]split-index] + [--[no-|test-|force-]untracked-cache] + [--[no-]fsmonitor] + [--really-refresh] [--unresolve] [--again | -g] + [--info-only] [--index-info] + [-z] [--stdin] [--index-version <n>] + [--verbose] + [--] [<file>...] + +DESCRIPTION +----------- +Modifies the index or directory cache. Each file mentioned is updated +into the index and any 'unmerged' or 'needs updating' state is +cleared. + +See also linkgit:git-add[1] for a more user-friendly way to do some of +the most common operations on the index. + +The way 'git update-index' handles files it is told about can be modified +using the various options: + +OPTIONS +------- +--add:: + If a specified file isn't in the index already then it's + added. + Default behaviour is to ignore new files. + +--remove:: + If a specified file is in the index but is missing then it's + removed. + Default behavior is to ignore removed file. + +--refresh:: + Looks at the current index and checks to see if merges or + updates are needed by checking stat() information. + +-q:: + Quiet. If --refresh finds that the index needs an update, the + default behavior is to error out. This option makes + 'git update-index' continue anyway. + +--ignore-submodules:: + Do not try to update submodules. This option is only respected + when passed before --refresh. + +--unmerged:: + If --refresh finds unmerged changes in the index, the default + behavior is to error out. This option makes 'git update-index' + continue anyway. + +--ignore-missing:: + Ignores missing files during a --refresh + +--cacheinfo <mode>,<object>,<path>:: +--cacheinfo <mode> <object> <path>:: + Directly insert the specified info into the index. For + backward compatibility, you can also give these three + arguments as three separate parameters, but new users are + encouraged to use a single-parameter form. + +--index-info:: + Read index information from stdin. + +--chmod=(+|-)x:: + Set the execute permissions on the updated files. + +--[no-]assume-unchanged:: + When this flag is specified, the object names recorded + for the paths are not updated. Instead, this option + sets/unsets the "assume unchanged" bit for the + paths. When the "assume unchanged" bit is on, the user + promises not to change the file and allows Git to assume + that the working tree file matches what is recorded in + the index. If you want to change the working tree file, + you need to unset the bit to tell Git. This is + sometimes helpful when working with a big project on a + filesystem that has very slow lstat(2) system call + (e.g. cifs). ++ +Git will fail (gracefully) in case it needs to modify this file +in the index e.g. when merging in a commit; +thus, in case the assumed-untracked file is changed upstream, +you will need to handle the situation manually. + +--really-refresh:: + Like `--refresh`, but checks stat information unconditionally, + without regard to the "assume unchanged" setting. + +--[no-]skip-worktree:: + When one of these flags is specified, the object name recorded + for the paths are not updated. Instead, these options + set and unset the "skip-worktree" bit for the paths. See + section "Skip-worktree bit" below for more information. + +--[no-]fsmonitor-valid:: + When one of these flags is specified, the object name recorded + for the paths are not updated. Instead, these options + set and unset the "fsmonitor valid" bit for the paths. See + section "File System Monitor" below for more information. + +-g:: +--again:: + Runs 'git update-index' itself on the paths whose index + entries are different from those from the `HEAD` commit. + +--unresolve:: + Restores the 'unmerged' or 'needs updating' state of a + file during a merge if it was cleared by accident. + +--info-only:: + Do not create objects in the object database for all + <file> arguments that follow this flag; just insert + their object IDs into the index. + +--force-remove:: + Remove the file from the index even when the working directory + still has such a file. (Implies --remove.) + +--replace:: + By default, when a file `path` exists in the index, + 'git update-index' refuses an attempt to add `path/file`. + Similarly if a file `path/file` exists, a file `path` + cannot be added. With --replace flag, existing entries + that conflict with the entry being added are + automatically removed with warning messages. + +--stdin:: + Instead of taking list of paths from the command line, + read list of paths from the standard input. Paths are + separated by LF (i.e. one path per line) by default. + +--verbose:: + Report what is being added and removed from index. + +--index-version <n>:: + Write the resulting index out in the named on-disk format version. + Supported versions are 2, 3 and 4. The current default version is 2 + or 3, depending on whether extra features are used, such as + `git add -N`. ++ +Version 4 performs a simple pathname compression that reduces index +size by 30%-50% on large repositories, which results in faster load +time. Version 4 is relatively young (first released in 1.8.0 in +October 2012). Other Git implementations such as JGit and libgit2 +may not support it yet. + +-z:: + Only meaningful with `--stdin` or `--index-info`; paths are + separated with NUL character instead of LF. + +--split-index:: +--no-split-index:: + Enable or disable split index mode. If split-index mode is + already enabled and `--split-index` is given again, all + changes in $GIT_DIR/index are pushed back to the shared index + file. ++ +These options take effect whatever the value of the `core.splitIndex` +configuration variable (see linkgit:git-config[1]). But a warning is +emitted when the change goes against the configured value, as the +configured value will take effect next time the index is read and this +will remove the intended effect of the option. + +--untracked-cache:: +--no-untracked-cache:: + Enable or disable untracked cache feature. Please use + `--test-untracked-cache` before enabling it. ++ +These options take effect whatever the value of the `core.untrackedCache` +configuration variable (see linkgit:git-config[1]). But a warning is +emitted when the change goes against the configured value, as the +configured value will take effect next time the index is read and this +will remove the intended effect of the option. + +--test-untracked-cache:: + Only perform tests on the working directory to make sure + untracked cache can be used. You have to manually enable + untracked cache using `--untracked-cache` or + `--force-untracked-cache` or the `core.untrackedCache` + configuration variable afterwards if you really want to use + it. If a test fails the exit code is 1 and a message + explains what is not working as needed, otherwise the exit + code is 0 and OK is printed. + +--force-untracked-cache:: + Same as `--untracked-cache`. Provided for backwards + compatibility with older versions of Git where + `--untracked-cache` used to imply `--test-untracked-cache` but + this option would enable the extension unconditionally. + +--fsmonitor:: +--no-fsmonitor:: + Enable or disable files system monitor feature. These options + take effect whatever the value of the `core.fsmonitor` + configuration variable (see linkgit:git-config[1]). But a warning + is emitted when the change goes against the configured value, as + the configured value will take effect next time the index is + read and this will remove the intended effect of the option. + +\--:: + Do not interpret any more arguments as options. + +<file>:: + Files to act on. + Note that files beginning with '.' are discarded. This includes + `./file` and `dir/./file`. If you don't want this, then use + cleaner names. + The same applies to directories ending '/' and paths with '//' + +USING --REFRESH +--------------- +`--refresh` does not calculate a new sha1 file or bring the index +up to date for mode/content changes. But what it *does* do is to +"re-match" the stat information of a file with the index, so that you +can refresh the index for a file that hasn't been changed but where +the stat entry is out of date. + +For example, you'd want to do this after doing a 'git read-tree', to link +up the stat index details with the proper files. + +USING --CACHEINFO OR --INFO-ONLY +-------------------------------- +`--cacheinfo` is used to register a file that is not in the +current working directory. This is useful for minimum-checkout +merging. + +To pretend you have a file at path with mode and sha1, say: + +---------------- +$ git update-index --add --cacheinfo <mode>,<sha1>,<path> +---------------- + +`--info-only` is used to register files without placing them in the object +database. This is useful for status-only repositories. + +Both `--cacheinfo` and `--info-only` behave similarly: the index is updated +but the object database isn't. `--cacheinfo` is useful when the object is +in the database but the file isn't available locally. `--info-only` is +useful when the file is available, but you do not wish to update the +object database. + + +USING --INDEX-INFO +------------------ + +`--index-info` is a more powerful mechanism that lets you feed +multiple entry definitions from the standard input, and designed +specifically for scripts. It can take inputs of three formats: + + . mode SP type SP sha1 TAB path ++ +This format is to stuff `git ls-tree` output into the index. + + . mode SP sha1 SP stage TAB path ++ +This format is to put higher order stages into the +index file and matches 'git ls-files --stage' output. + + . mode SP sha1 TAB path ++ +This format is no longer produced by any Git command, but is +and will continue to be supported by `update-index --index-info`. + +To place a higher stage entry to the index, the path should +first be removed by feeding a mode=0 entry for the path, and +then feeding necessary input lines in the third format. + +For example, starting with this index: + +------------ +$ git ls-files -s +100644 8a1218a1024a212bb3db30becd860315f9f3ac52 0 frotz +------------ + +you can feed the following input to `--index-info`: + +------------ +$ git update-index --index-info +0 0000000000000000000000000000000000000000 frotz +100644 8a1218a1024a212bb3db30becd860315f9f3ac52 1 frotz +100755 8a1218a1024a212bb3db30becd860315f9f3ac52 2 frotz +------------ + +The first line of the input feeds 0 as the mode to remove the +path; the SHA-1 does not matter as long as it is well formatted. +Then the second and third line feeds stage 1 and stage 2 entries +for that path. After the above, we would end up with this: + +------------ +$ git ls-files -s +100644 8a1218a1024a212bb3db30becd860315f9f3ac52 1 frotz +100755 8a1218a1024a212bb3db30becd860315f9f3ac52 2 frotz +------------ + + +USING ``ASSUME UNCHANGED'' BIT +------------------------------ + +Many operations in Git depend on your filesystem to have an +efficient `lstat(2)` implementation, so that `st_mtime` +information for working tree files can be cheaply checked to see +if the file contents have changed from the version recorded in +the index file. Unfortunately, some filesystems have +inefficient `lstat(2)`. If your filesystem is one of them, you +can set "assume unchanged" bit to paths you have not changed to +cause Git not to do this check. Note that setting this bit on a +path does not mean Git will check the contents of the file to +see if it has changed -- it makes Git to omit any checking and +assume it has *not* changed. When you make changes to working +tree files, you have to explicitly tell Git about it by dropping +"assume unchanged" bit, either before or after you modify them. + +In order to set "assume unchanged" bit, use `--assume-unchanged` +option. To unset, use `--no-assume-unchanged`. To see which files +have the "assume unchanged" bit set, use `git ls-files -v` +(see linkgit:git-ls-files[1]). + +The command looks at `core.ignorestat` configuration variable. When +this is true, paths updated with `git update-index paths...` and +paths updated with other Git commands that update both index and +working tree (e.g. 'git apply --index', 'git checkout-index -u', +and 'git read-tree -u') are automatically marked as "assume +unchanged". Note that "assume unchanged" bit is *not* set if +`git update-index --refresh` finds the working tree file matches +the index (use `git update-index --really-refresh` if you want +to mark them as "assume unchanged"). + + +EXAMPLES +-------- +To update and refresh only the files already checked out: + +---------------- +$ git checkout-index -n -f -a && git update-index --ignore-missing --refresh +---------------- + +On an inefficient filesystem with `core.ignorestat` set:: ++ +------------ +$ git update-index --really-refresh <1> +$ git update-index --no-assume-unchanged foo.c <2> +$ git diff --name-only <3> +$ edit foo.c +$ git diff --name-only <4> +M foo.c +$ git update-index foo.c <5> +$ git diff --name-only <6> +$ edit foo.c +$ git diff --name-only <7> +$ git update-index --no-assume-unchanged foo.c <8> +$ git diff --name-only <9> +M foo.c +------------ ++ +<1> forces lstat(2) to set "assume unchanged" bits for paths that match index. +<2> mark the path to be edited. +<3> this does lstat(2) and finds index matches the path. +<4> this does lstat(2) and finds index does *not* match the path. +<5> registering the new version to index sets "assume unchanged" bit. +<6> and it is assumed unchanged. +<7> even after you edit it. +<8> you can tell about the change after the fact. +<9> now it checks with lstat(2) and finds it has been changed. + + +SKIP-WORKTREE BIT +----------------- + +Skip-worktree bit can be defined in one (long) sentence: When reading +an entry, if it is marked as skip-worktree, then Git pretends its +working directory version is up to date and read the index version +instead. + +To elaborate, "reading" means checking for file existence, reading +file attributes or file content. The working directory version may be +present or absent. If present, its content may match against the index +version or not. Writing is not affected by this bit, content safety +is still first priority. Note that Git _can_ update working directory +file, that is marked skip-worktree, if it is safe to do so (i.e. +working directory version matches index version) + +Although this bit looks similar to assume-unchanged bit, its goal is +different from assume-unchanged bit's. Skip-worktree also takes +precedence over assume-unchanged bit when both are set. + +SPLIT INDEX +----------- + +This mode is designed for repositories with very large indexes, and +aims at reducing the time it takes to repeatedly write these indexes. + +In this mode, the index is split into two files, $GIT_DIR/index and +$GIT_DIR/sharedindex.<SHA-1>. Changes are accumulated in +$GIT_DIR/index, the split index, while the shared index file contains +all index entries and stays unchanged. + +All changes in the split index are pushed back to the shared index +file when the number of entries in the split index reaches a level +specified by the splitIndex.maxPercentChange config variable (see +linkgit:git-config[1]). + +Each time a new shared index file is created, the old shared index +files are deleted if their modification time is older than what is +specified by the splitIndex.sharedIndexExpire config variable (see +linkgit:git-config[1]). + +To avoid deleting a shared index file that is still used, its +modification time is updated to the current time everytime a new split +index based on the shared index file is either created or read from. + +UNTRACKED CACHE +--------------- + +This cache is meant to speed up commands that involve determining +untracked files such as `git status`. + +This feature works by recording the mtime of the working tree +directories and then omitting reading directories and stat calls +against files in those directories whose mtime hasn't changed. For +this to work the underlying operating system and file system must +change the `st_mtime` field of directories if files in the directory +are added, modified or deleted. + +You can test whether the filesystem supports that with the +`--test-untracked-cache` option. The `--untracked-cache` option used +to implicitly perform that test in older versions of Git, but that's +no longer the case. + +If you want to enable (or disable) this feature, it is easier to use +the `core.untrackedCache` configuration variable (see +linkgit:git-config[1]) than using the `--untracked-cache` option to +`git update-index` in each repository, especially if you want to do so +across all repositories you use, because you can set the configuration +variable to `true` (or `false`) in your `$HOME/.gitconfig` just once +and have it affect all repositories you touch. + +When the `core.untrackedCache` configuration variable is changed, the +untracked cache is added to or removed from the index the next time a +command reads the index; while when `--[no-|force-]untracked-cache` +are used, the untracked cache is immediately added to or removed from +the index. + +Before 2.17, the untracked cache had a bug where replacing a directory +with a symlink to another directory could cause it to incorrectly show +files tracked by git as untracked. See the "status: add a failing test +showing a core.untrackedCache bug" commit to git.git. A workaround for +that is (and this might work for other undiscovered bugs in the +future): + +---------------- +$ git -c core.untrackedCache=false status +---------------- + +This bug has also been shown to affect non-symlink cases of replacing +a directory with a file when it comes to the internal structures of +the untracked cache, but no case has been reported where this resulted in +wrong "git status" output. + +There are also cases where existing indexes written by git versions +before 2.17 will reference directories that don't exist anymore, +potentially causing many "could not open directory" warnings to be +printed on "git status". These are new warnings for existing issues +that were previously silently discarded. + +As with the bug described above the solution is to one-off do a "git +status" run with `core.untrackedCache=false` to flush out the leftover +bad data. + +FILE SYSTEM MONITOR +------------------- + +This feature is intended to speed up git operations for repos that have +large working directories. + +It enables git to work together with a file system monitor (see the +"fsmonitor-watchman" section of linkgit:githooks[5]) that can +inform it as to what files have been modified. This enables git to avoid +having to lstat() every file to find modified files. + +When used in conjunction with the untracked cache, it can further improve +performance by avoiding the cost of scanning the entire working directory +looking for new files. + +If you want to enable (or disable) this feature, it is easier to use +the `core.fsmonitor` configuration variable (see +linkgit:git-config[1]) than using the `--fsmonitor` option to +`git update-index` in each repository, especially if you want to do so +across all repositories you use, because you can set the configuration +variable in your `$HOME/.gitconfig` just once and have it affect all +repositories you touch. + +When the `core.fsmonitor` configuration variable is changed, the +file system monitor is added to or removed from the index the next time +a command reads the index. When `--[no-]fsmonitor` are used, the file +system monitor is immediately added to or removed from the index. + +CONFIGURATION +------------- + +The command honors `core.filemode` configuration variable. If +your repository is on a filesystem whose executable bits are +unreliable, this should be set to 'false' (see linkgit:git-config[1]). +This causes the command to ignore differences in file modes recorded +in the index and the file mode on the filesystem if they differ only on +executable bit. On such an unfortunate filesystem, you may +need to use 'git update-index --chmod='. + +Quite similarly, if `core.symlinks` configuration variable is set +to 'false' (see linkgit:git-config[1]), symbolic links are checked out +as plain files, and this command does not modify a recorded file mode +from symbolic link to regular file. + +The command looks at `core.ignorestat` configuration variable. See +'Using "assume unchanged" bit' section above. + +The command also looks at `core.trustctime` configuration variable. +It can be useful when the inode change time is regularly modified by +something outside Git (file system crawlers and backup systems use +ctime for marking files processed) (see linkgit:git-config[1]). + +The untracked cache extension can be enabled by the +`core.untrackedCache` configuration variable (see +linkgit:git-config[1]). + +SEE ALSO +-------- +linkgit:git-config[1], +linkgit:git-add[1], +linkgit:git-ls-files[1] + +GIT +--- +Part of the linkgit:git[1] suite |