Ubuntu Manpage: git-sparse-checkout - Reduce your working tree to a subset of tracked files

Provided by: git-man_2.45.2-1ubuntu1_all

NAME

       git-sparse-checkout - Reduce your working tree to a subset of tracked files

SYNOPSIS

       git sparse-checkout (init | list | set | add | reapply | disable | check-rules) [<options>]

DESCRIPTION

       This command is used to create sparse checkouts, which change the working tree from having
       all tracked files present to only having a subset of those files. It can also switch which
       subset of files are present, or undo and go back to having all tracked files present in
       the working copy.

       The subset of files is chosen by providing a list of directories in cone mode (the
       default), or by providing a list of patterns in non-cone mode.

       When in a sparse-checkout, other Git commands behave a bit differently. For example,
       switching branches will not update paths outside the sparse-checkout directories/patterns,
       and git commit -a will not record paths outside the sparse-checkout directories/patterns
       as deleted.

       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 directories or patterns in the sparse-checkout file.

set
Enable the necessary sparse-checkout config settings (core.sparseCheckout,
core.sparseCheckoutCone, and index.sparse) if they are not already set to the desired
values, populate the sparse-checkout file from the list of arguments following the set
subcommand, and update the working directory to match.

To ensure that adjusting the sparse-checkout settings within a worktree does not alter
the sparse-checkout settings in other worktrees, the set subcommand will upgrade your
repository config to use worktree-specific config if not already present. The sparsity
defined by the arguments to the set subcommand are stored in the worktree-specific
sparse-checkout file. See git-worktree(1) and the documentation of
extensions.worktreeConfig in git-config(1) for more details.

When the --stdin option is provided, the directories or patterns are read from
standard in as a newline-delimited list instead of from the arguments.

By default, the input list is considered a list of directories, matching the output of
git ls-tree -d --name-only. This includes interpreting pathnames that begin with a
double quote (") as C-style quoted strings. Note that all files under the specified
directories (at any depth) will be included in the sparse checkout, as well as files
that are siblings of either the given directory or any of its ancestors (see CONE
PATTERN SET below for more details). In the past, this was not the default, and --cone
needed to be specified or core.sparseCheckoutCone needed to be enabled.

When --no-cone is passed, the input list is considered a list of patterns. This mode
has a number of drawbacks, including not working with some options like
--sparse-index. As explained in the "Non-cone Problems" section below, we do not
recommend using it.

Use the --[no-]sparse-index option to use a sparse index (the default is to not use
it). A sparse index reduces the size of the index to be more closely aligned with your
sparse-checkout definition. This can have significant performance advantages for
commands such as git status or git add. This feature is still experimental. Some
commands might be slower with a sparse index until they are properly integrated with
the feature.

WARNING: Using a sparse index requires modifying the index in a way that is not
completely understood by external tools. If you have trouble with this compatibility,
then run git sparse-checkout init --no-sparse-index to rewrite your index to not be
sparse. Older versions of Git will not understand the sparse directory entries index
extension and may fail to interact with your repository until it is disabled.

add
Update the sparse-checkout file to include additional directories (in cone mode) or
patterns (in non-cone mode). By default, these directories or patterns are read from
the command-line arguments, but they can be read from stdin using the --stdin option.

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.).

The reapply command can also take --[no-]cone and --[no-]sparse-index flags, with the
same meaning as the flags from the set command, in order to change which sparsity mode
you are using without needing to also respecify all sparsity paths.

disable
Disable the core.sparseCheckout config setting, and restore the working directory to
include all files.

init
Deprecated command that behaves like set with no specified paths. May be removed in
the future.

Historically, set did not handle all the necessary config settings, which meant that
both init and set had to be called. Invoking both meant the init step would first
remove nearly all tracked files (and in cone mode, ignored files too), then the set
step would add many of the tracked files (but not ignored files) back. In addition to
the lost files, the performance and UI of this combination was poor.

Also, historically, init would not actually initialize the sparse-checkout file if it
already existed. This meant it was possible to return to a sparse-checkout without
remembering which paths to pass to a subsequent set or add command. However, --cone
and --sparse-index options would not be remembered across the disable command, so the
easy restore of calling a plain init decreased in utility.

check-rules
Check whether sparsity rules match one or more paths.

By default check-rules reads a list of paths from stdin and outputs only the ones that
match the current sparsity rules. The input is expected to consist of one path per
line, matching the output of git ls-tree --name-only including that pathnames that
begin with a double quote (") are interpreted as C-style quoted strings.

When called with the --rules-file <file> flag the input files are matched against the
sparse checkout rules found in <file> instead of the current ones. The rules in the
files are expected to be in the same form as accepted by git sparse-checkout set
--stdin (in particular, they must be newline-delimited).

By default, the rules passed to the --rules-file option are interpreted as cone mode
directories. To pass non-cone mode patterns with --rules-file, combine the option with
the --no-cone option.

When called with the -z flag, the format of the paths input on stdin as well as the
output paths are \0 terminated and not quoted. Note that this does not apply to the
format of the rules passed with the --rules-file option.

EXAMPLES

git sparse-checkout set MY/DIR1 SUB/DIR2
Change to a sparse checkout with all files (at any depth) under MY/DIR1/ and SUB/DIR2/
present in the working copy (plus all files immediately under MY/ and SUB/ and the
toplevel directory). If already in a sparse checkout, change which files are present
in the working copy to this new selection. Note that this command will also delete all
ignored files in any directory that no longer has either tracked or
non-ignored-untracked files present.

git sparse-checkout disable
Repopulate the working directory with all files, disabling sparse checkouts.

git sparse-checkout add SOME/DIR/ECTORY
Add all files under SOME/DIR/ECTORY/ (at any depth) to the sparse checkout, as well as
all files immediately under SOME/DIR/ and immediately under SOME/. Must already be in
a sparse checkout before using this command.

git sparse-checkout reapply
It is possible for commands to update the working tree in a way that does not respect
the selected sparsity directories. This can come from tools external to Git writing
files, or even affect Git commands because of either special cases (such as hitting
conflicts when merging/rebasing), or because some commands didn’t fully support sparse
checkouts (e.g. the old recursive merge backend had only limited support). This
command reapplies the existing sparse directory specifications to make the working
directory match.

INTERNALS — SPARSE CHECKOUT

       "Sparse checkout" allows populating the working directory sparsely. It uses the
       skip-worktree bit (see 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, and the file is not
       present in the working tree, then its absence is ignored. Git will avoid populating 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.

INTERNALS — NON-CONE PROBLEMS

The $GIT_DIR/info/sparse-checkout file populated by the set and add subcommands is defined
to be a bunch of patterns (one per line) using the same syntax as .gitignore files. In
cone mode, these patterns are restricted to matching directories (and users only ever need
supply or see directory names), while in non-cone mode any gitignore-style pattern is
permitted. Using the full gitignore-style patterns in non-cone mode has a number of
shortcomings:

• Fundamentally, it makes various worktree-updating processes (pull, merge, rebase,
switch, reset, checkout, etc.) require O(N*M) pattern matches, where N is the number
of patterns and M is the number of paths in the index. This scales poorly.

• Avoiding the scaling issue has to be done via limiting the number of patterns via
specifying leading directory name or glob.

• Passing globs on the command line is error-prone as users may forget to quote the
glob, causing the shell to expand it into all matching files and pass them all
individually along to sparse-checkout set/add. While this could also be a problem with
e.g. "git grep — *.c", mistakes with grep/log/status appear in the immediate output.
With sparse-checkout, the mistake gets recorded at the time the sparse-checkout
command is run and might not be problematic until the user later switches branches or
rebases or merges, thus putting a delay between the user’s error and when they have a
chance to catch/notice it.

• Related to the previous item, sparse-checkout has an add subcommand but no remove
subcommand. Even if a remove subcommand were added, undoing an accidental unquoted
glob runs the risk of "removing too much", as it may remove entries that had been
included before the accidental add.

• Non-cone mode uses gitignore-style patterns to select what to include (with the
exception of negated patterns), while .gitignore files use gitignore-style patterns to
select what to exclude (with the exception of negated patterns). The documentation on
gitignore-style patterns usually does not talk in terms of matching or non-matching,
but on what the user wants to "exclude". This can cause confusion for users trying to
learn how to specify sparse-checkout patterns to get their desired behavior.

• Every other git subcommand that wants to provide "special path pattern matching" of
some sort uses pathspecs, but non-cone mode for sparse-checkout uses gitignore
patterns, which feels inconsistent.

• It has edge cases where the "right" behavior is unclear. Two examples:

First, two users are in a subdirectory, and the first runs
git sparse-checkout set '/toplevel-dir/*.c'
while the second runs
git sparse-checkout set relative-dir
Should those arguments be transliterated into
current/subdirectory/toplevel-dir/*.c
and
current/subdirectory/relative-dir
before inserting into the sparse-checkout file? The user who typed
the first command is probably aware that arguments to set/add are
supposed to be patterns in non-cone mode, and probably would not be
happy with such a transliteration. However, many gitignore-style
patterns are just paths, which might be what the user who typed the
second command was thinking, and they'd be upset if their argument
wasn't transliterated.

Second, what should bash-completion complete on for set/add commands
for non-cone users? If it suggests paths, is it exacerbating the
problem above? Also, if it suggests paths, what if the user has a
file or directory that begins with either a '!' or '#' or has a '*',
'\', '?', '[', or ']' in its name? And if it suggests paths, will
it complete "/pro" to "/proc" (in the root filesystem) rather than to
"/progress.txt" in the current directory? (Note that users are
likely to want to start paths with a leading '/' in non-cone mode,
for the same reason that .gitignore files often have one.)
Completing on files or directories might give nasty surprises in
all these cases.

• The excessive flexibility made other extensions essentially impractical.
--sparse-index is likely impossible in non-cone mode; even if it is somehow feasible,
it would have been far more work to implement and may have been too slow in practice.
Some ideas for adding coupling between partial clones and sparse checkouts are only
practical with a more restricted set of paths as well.

For all these reasons, non-cone mode is deprecated. Please switch to using cone mode.

INTERNALS — CONE MODE HANDLING

       The "cone mode", which is the default, lets you specify only what directories to include.
       For any directory specified, all paths below that directory will be included, and any
       paths immediately under leading directories (including the toplevel directory) will also
       be included. Thus, if you specified the directory Documentation/technical/ then your
       sparse checkout would contain:

       •   all files in the toplevel-directory

       •   all files immediately under Documentation/

       •   all files at any depth under Documentation/technical/

       Also, in cone mode, even if no directories are specified, then the files in the toplevel
       directory will be included.

       When changing the sparse-checkout patterns in cone mode, Git will inspect each tracked
       directory that is not within the sparse-checkout cone to see if it contains any untracked
       files. If all of those files are ignored due to the .gitignore patterns, then the
       directory will be deleted. If any of the untracked files within that directory is not
       ignored, then no deletions will occur within that directory and a warning message will
       appear. If these files are important, then reset your sparse-checkout definition so they
       are included, use git add and git commit to store them, then remove any remaining files
       manually to ensure Git can behave optimally.

       See also the "Internals — Cone Pattern Set" section to learn how the directories are
       transformed under the hood into a subset of the Full Pattern Set of sparse-checkout.

INTERNALS — FULL 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 sparse-checkout file uses the same syntax as .gitignore files; see gitignore(5) for
       details. Here, though, the patterns are usually being used to select which files to
       include rather than which files to exclude. (However, it can get a bit confusing since
       gitignore-style patterns have negations defined by patterns which begin with a !, so you
       can also select files to not include.)

       For example, to select everything, and then to remove the file unwanted (so that every
       file will appear in your working tree except the file named unwanted):

           git sparse-checkout set --no-cone '/*' '!unwanted'

       These patterns are just placed into the $GIT_DIR/info/sparse-checkout as-is, so the
       contents of that file at this point would be

           /*
           !unwanted

       See also the "Sparse Checkout" section of git-read-tree(1) to learn more about the
       gitignore-style patterns used in sparse checkouts.

INTERNALS — CONE PATTERN SET

In cone mode, only directories are accepted, but they are translated into the same
gitignore-style patterns used in the full pattern set. We refer to the particular patterns
used in those mode as being of one of two types:

1. Recursive: All paths inside a directory are included.

2. Parent: All files immediately inside a directory are included.

Since cone mode always includes files at the toplevel, when running git sparse-checkout
set with no directories specified, the toplevel directory is added as a parent pattern. At
this point, the sparse-checkout file contains the following patterns:

/*
!/*/

This says "include everything immediately under the toplevel directory, but nothing at any
level below that."

When in cone mode, the git sparse-checkout set subcommand takes a list of directories. 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.

Unless core.sparseCheckoutCone is explicitly set to false, 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. If they do not match,
git will behave as though core.sparseCheckoutCone was false, regardless of its setting.

In the cone mode case, despite the fact that full patterns are written to the
$GIT_DIR/info/sparse-checkout file, 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.

INTERNALS — 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.

GIT

       Part of the git(1) suite