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diff --git a/third_party/git/Documentation/git-sparse-checkout.txt b/third_party/git/Documentation/git-sparse-checkout.txt new file mode 100644 index 000000000000..a0eeaeb02ee3 --- /dev/null +++ b/third_party/git/Documentation/git-sparse-checkout.txt @@ -0,0 +1,239 @@ +git-sparse-checkout(1) +====================== + +NAME +---- +git-sparse-checkout - Initialize and modify the sparse-checkout +configuration, which reduces the checkout to a set of paths +given by a list of patterns. + + +SYNOPSIS +-------- +[verse] +'git sparse-checkout <subcommand> [options]' + + +DESCRIPTION +----------- + +Initialize and modify the sparse-checkout configuration, which reduces +the checkout to a set of paths given by a list of patterns. + +THIS COMMAND IS EXPERIMENTAL. ITS BEHAVIOR, AND THE BEHAVIOR OF OTHER +COMMANDS IN THE PRESENCE OF SPARSE-CHECKOUTS, WILL LIKELY CHANGE IN +THE FUTURE. + + +COMMANDS +-------- +'list':: + Describe the patterns in the sparse-checkout file. + +'init':: + Enable the `core.sparseCheckout` setting. If the + sparse-checkout file does not exist, then populate it with + patterns that match every file in the root directory and + no other directories, then will remove all directories tracked + by Git. Add patterns to the sparse-checkout file to + repopulate the working directory. ++ +To avoid interfering with other worktrees, it first enables the +`extensions.worktreeConfig` setting and makes sure to set the +`core.sparseCheckout` setting in the worktree-specific config file. ++ +When `--cone` is provided, the `core.sparseCheckoutCone` setting is +also set, allowing for better performance with a limited set of +patterns (see 'CONE PATTERN SET' below). + +'set':: + Write a set of patterns to the sparse-checkout file, as given as + a list of arguments following the 'set' subcommand. Update the + working directory to match the new patterns. Enable the + core.sparseCheckout config setting if it is not already enabled. ++ +When the `--stdin` option is provided, the patterns are read from +standard in as a newline-delimited list instead of from the arguments. ++ +When `core.sparseCheckoutCone` is enabled, the input list is considered a +list of directories instead of sparse-checkout patterns. The command writes +patterns to the sparse-checkout file to include all files contained in those +directories (recursively) as well as files that are siblings of ancestor +directories. The input format matches the output of `git ls-tree --name-only`. +This includes interpreting pathnames that begin with a double quote (") as +C-style quoted strings. + +'add':: + Update the sparse-checkout file to include additional patterns. + By default, these patterns are read from the command-line arguments, + but they can be read from stdin using the `--stdin` option. When + `core.sparseCheckoutCone` is enabled, the given patterns are interpreted + as directory names as in the 'set' subcommand. + +'reapply':: + Reapply the sparsity pattern rules to paths in the working tree. + Commands like merge or rebase can materialize paths to do their + work (e.g. in order to show you a conflict), and other + sparse-checkout commands might fail to sparsify an individual file + (e.g. because it has unstaged changes or conflicts). In such + cases, it can make sense to run `git sparse-checkout reapply` later + after cleaning up affected paths (e.g. resolving conflicts, undoing + or committing changes, etc.). + +'disable':: + Disable the `core.sparseCheckout` config setting, and restore the + working directory to include all files. Leaves the sparse-checkout + file intact so a later 'git sparse-checkout init' command may + return the working directory to the same state. + +SPARSE CHECKOUT +--------------- + +"Sparse checkout" allows populating the working directory sparsely. +It uses the skip-worktree bit (see linkgit:git-update-index[1]) to tell +Git whether a file in the working directory is worth looking at. If +the skip-worktree bit is set, then the file is ignored in the working +directory. Git will not populate the contents of those files, which +makes a sparse checkout helpful when working in a repository with many +files, but only a few are important to the current user. + +The `$GIT_DIR/info/sparse-checkout` file is used to define the +skip-worktree reference bitmap. When Git updates the working +directory, it updates the skip-worktree bits in the index based +on this file. The files matching the patterns in the file will +appear in the working directory, and the rest will not. + +To enable the sparse-checkout feature, run `git sparse-checkout init` to +initialize a simple sparse-checkout file and enable the `core.sparseCheckout` +config setting. Then, run `git sparse-checkout set` to modify the patterns in +the sparse-checkout file. + +To repopulate the working directory with all files, use the +`git sparse-checkout disable` command. + + +FULL PATTERN SET +---------------- + +By default, the sparse-checkout file uses the same syntax as `.gitignore` +files. + +While `$GIT_DIR/info/sparse-checkout` is usually used to specify what +files are included, you can also specify what files are _not_ included, +using negative patterns. For example, to remove the file `unwanted`: + +---------------- +/* +!unwanted +---------------- + + +CONE PATTERN SET +---------------- + +The full pattern set allows for arbitrary pattern matches and complicated +inclusion/exclusion rules. These can result in O(N*M) pattern matches when +updating the index, where N is the number of patterns and M is the number +of paths in the index. To combat this performance issue, a more restricted +pattern set is allowed when `core.sparseCheckoutCone` is enabled. + +The accepted patterns in the cone pattern set are: + +1. *Recursive:* All paths inside a directory are included. + +2. *Parent:* All files immediately inside a directory are included. + +In addition to the above two patterns, we also expect that all files in the +root directory are included. If a recursive pattern is added, then all +leading directories are added as parent patterns. + +By default, when running `git sparse-checkout init`, the root directory is +added as a parent pattern. At this point, the sparse-checkout file contains +the following patterns: + +---------------- +/* +!/*/ +---------------- + +This says "include everything in root, but nothing two levels below root." + +When in cone mode, the `git sparse-checkout set` subcommand takes a list of +directories instead of a list of sparse-checkout patterns. In this mode, +the command `git sparse-checkout set A/B/C` sets the directory `A/B/C` as +a recursive pattern, the directories `A` and `A/B` are added as parent +patterns. The resulting sparse-checkout file is now + +---------------- +/* +!/*/ +/A/ +!/A/*/ +/A/B/ +!/A/B/*/ +/A/B/C/ +---------------- + +Here, order matters, so the negative patterns are overridden by the positive +patterns that appear lower in the file. + +If `core.sparseCheckoutCone=true`, then Git will parse the sparse-checkout file +expecting patterns of these types. Git will warn if the patterns do not match. +If the patterns do match the expected format, then Git will use faster hash- +based algorithms to compute inclusion in the sparse-checkout. + +In the cone mode case, the `git sparse-checkout list` subcommand will list the +directories that define the recursive patterns. For the example sparse-checkout +file above, the output is as follows: + +-------------------------- +$ git sparse-checkout list +A/B/C +-------------------------- + +If `core.ignoreCase=true`, then the pattern-matching algorithm will use a +case-insensitive check. This corrects for case mismatched filenames in the +'git sparse-checkout set' command to reflect the expected cone in the working +directory. + + +SUBMODULES +---------- + +If your repository contains one or more submodules, then submodules +are populated based on interactions with the `git submodule` command. +Specifically, `git submodule init -- <path>` will ensure the submodule +at `<path>` is present, while `git submodule deinit [-f] -- <path>` +will remove the files for the submodule at `<path>` (including any +untracked files, uncommitted changes, and unpushed history). Similar +to how sparse-checkout removes files from the working tree but still +leaves entries in the index, deinitialized submodules are removed from +the working directory but still have an entry in the index. + +Since submodules may have unpushed changes or untracked files, +removing them could result in data loss. Thus, changing sparse +inclusion/exclusion rules will not cause an already checked out +submodule to be removed from the working copy. Said another way, just +as `checkout` will not cause submodules to be automatically removed or +initialized even when switching between branches that remove or add +submodules, using `sparse-checkout` to reduce or expand the scope of +"interesting" files will not cause submodules to be automatically +deinitialized or initialized either. + +Further, the above facts mean that there are multiple reasons that +"tracked" files might not be present in the working copy: sparsity +pattern application from sparse-checkout, and submodule initialization +state. Thus, commands like `git grep` that work on tracked files in +the working copy may return results that are limited by either or both +of these restrictions. + + +SEE ALSO +-------- + +linkgit:git-read-tree[1] +linkgit:gitignore[5] + +GIT +--- +Part of the linkgit:git[1] suite |