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Diffstat (limited to 'Documentation/git-update-index.txt')
| -rw-r--r-- | Documentation/git-update-index.txt | 78 |
1 files changed, 78 insertions, 0 deletions
diff --git a/Documentation/git-update-index.txt b/Documentation/git-update-index.txt index c74311dabd..0a1b0ad56d 100644 --- a/Documentation/git-update-index.txt +++ b/Documentation/git-update-index.txt @@ -8,11 +8,14 @@ git-update-index - Modifies the index or directory cache SYNOPSIS -------- +[verse] 'git-update-index' [--add] [--remove | --force-remove] [--replace] [--refresh [-q] [--unmerged] [--ignore-missing]] [--cacheinfo <mode> <object> <file>]\* [--chmod=(+|-)x] + [--assume-unchanged | --no-assume-unchanged] + [--really-refresh] [--info-only] [--index-info] [-z] [--stdin] [--verbose] @@ -65,6 +68,18 @@ OPTIONS --chmod=(+|-)x:: Set the execute permissions on the updated files. +--assume-unchanged, --no-assume-unchanged:: + When these flags are specified, the object name recorded + for the paths are not updated. Instead, these options + sets and unsets the "assume unchanged" bit for the + paths. When the "assume unchanged" bit is on, git stops + checking the working tree files for possible + modifications, so you need to manually unset the bit to + tell git when you change the working tree file. This is + sometimes helpful when working with a big project on a + filesystem that has very slow lstat(2) system call + (e.g. cifs). + --info-only:: Do not create objects in the object database for all <file> arguments that follow this flag; just insert @@ -193,6 +208,37 @@ $ git ls-files -s ------------ +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`. + +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: @@ -201,6 +247,35 @@ 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. +------------ + Configuration ------------- @@ -213,6 +288,9 @@ 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=`. +The command looks at `core.ignorestat` configuration variable. See +'Using "assume unchanged" bit' section above. + See Also -------- |