Merge branch 'en/sparse-cone-becomes-default'
Deprecate non-cone mode of the sparse-checkout feature. * en/sparse-cone-becomes-default: Documentation: some sparsity wording clarifications git-sparse-checkout.txt: mark non-cone mode as deprecated git-sparse-checkout.txt: flesh out pattern set sections a bit git-sparse-checkout.txt: add a new EXAMPLES section git-sparse-checkout.txt: shuffle some sections and mark as internal git-sparse-checkout.txt: update docs for deprecation of 'init' git-sparse-checkout.txt: wording updates for the cone mode default sparse-checkout: make --cone the default tests: stop assuming --no-cone is the default mode for sparse-checkout
This commit is contained in:
Junio C Hamano
@ -698,8 +698,10 @@ core.sparseCheckout::
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core.sparseCheckoutCone::
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Enables the "cone mode" of the sparse checkout feature. When the
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sparse-checkout file contains a limited set of patterns, then this
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mode provides significant performance advantages. See
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sparse-checkout file contains a limited set of patterns, this
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mode provides significant performance advantages. The "non
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cone mode" can be requested to allow specifying a more flexible
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patterns by setting this variable to 'false'. See
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linkgit:git-sparse-checkout[1] for more information.
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core.abbrev::
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@ -375,10 +375,13 @@ have finished your work-in-progress), attempt the merge again.
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SPARSE CHECKOUT
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---------------
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Note: The `update-index` and `read-tree` primitives for supporting the
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skip-worktree bit predated the introduction of
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linkgit:git-sparse-checkout[1]. Users are encouraged to use
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`sparse-checkout` in preference to these low-level primitives.
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Note: The skip-worktree capabilities in linkgit:git-update-index[1]
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and `read-tree` predated the introduction of
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linkgit:git-sparse-checkout[1]. Users are encouraged to use the
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`sparse-checkout` command in preference to these plumbing commands for
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sparse-checkout/skip-worktree related needs. However, the information
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below might be useful to users trying to understand the pattern style
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used in non-cone mode of the `sparse-checkout` command.
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"Sparse checkout" allows populating the working directory sparsely.
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It uses the skip-worktree bit (see linkgit:git-update-index[1]) to
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@ -15,15 +15,15 @@ SYNOPSIS
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DESCRIPTION
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-----------
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This command is used to create sparse checkouts, which means that it
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changes the working tree from having all tracked files present, to only
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have a subset of them. It can also switch which subset of files are
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present, or undo and go back to having all tracked files present in the
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working copy.
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This command is used to create sparse checkouts, which change the
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working tree from having all tracked files present to only having a
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subset of those files. It can also switch which subset of files are
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present, or undo and go back to having all tracked files present in
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the working copy.
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The subset of files is chosen by providing a list of directories in
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cone mode (which is recommended), or by providing a list of patterns
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in non-cone mode.
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cone mode (the default), or by providing a list of patterns in
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non-cone mode.
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When in a sparse-checkout, other Git commands behave a bit differently.
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For example, switching branches will not update paths outside the
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@ -44,9 +44,9 @@ COMMANDS
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Enable the necessary sparse-checkout config settings
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(`core.sparseCheckout`, `core.sparseCheckoutCone`, and
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`index.sparse`) if they are not already set to the desired values,
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and write a set of patterns to the sparse-checkout file from the
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list of arguments following the 'set' subcommand. Update the
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working directory to match the new patterns.
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populate the sparse-checkout file from the list of arguments
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following the 'set' subcommand, and update the working directory to
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match.
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+
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To ensure that adjusting the sparse-checkout settings within a worktree
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does not alter the sparse-checkout settings in other worktrees, the 'set'
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@ -60,22 +60,20 @@ When the `--stdin` option is provided, the directories or patterns are
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read from standard in as a newline-delimited list instead of from the
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arguments.
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+
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When `--cone` is passed or `core.sparseCheckoutCone` is enabled, the
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input list is considered a list of directories. This allows for
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better performance with a limited set of patterns (see 'CONE PATTERN
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SET' below). The input format matches the output of `git ls-tree
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--name-only`. This includes interpreting pathnames that begin with a
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double quote (") as C-style quoted strings. Note that the set command
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will write patterns to the sparse-checkout file to include all files
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contained in those directories (recursively) as well as files that are
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siblings of ancestor directories. This may become the default in the
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future; --no-cone can be passed to request non-cone mode.
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By default, the input list is considered a list of directories, matching
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the output of `git ls-tree -d --name-only`. This includes interpreting
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pathnames that begin with a double quote (") as C-style quoted strings.
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Note that all files under the specified directories (at any depth) will
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be included in the sparse checkout, as well as files that are siblings
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of either the given directory or any of its ancestors (see 'CONE PATTERN
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SET' below for more details). In the past, this was not the default,
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and `--cone` needed to be specified or `core.sparseCheckoutCone` needed
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to be enabled.
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+
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When `--no-cone` is passed or `core.sparseCheckoutCone` is not enabled,
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the input list is considered a list of patterns. This mode is harder
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to use and less performant, and is thus not recommended. See the
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"Sparse Checkout" section of linkgit:git-read-tree[1] and the "Pattern
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Set" sections below for more details.
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When `--no-cone` is passed, the input list is considered a list of
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patterns. This mode has a number of drawbacks, including not working
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with some options like `--sparse-index`. As explained in the
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"Non-cone Problems" section below, we do not recommend using it.
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+
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Use the `--[no-]sparse-index` option to use a sparse index (the
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default is to not use it). A sparse index reduces the size of the
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@ -137,8 +135,45 @@ paths to pass to a subsequent 'set' or 'add' command. However,
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the disable command, so the easy restore of calling a plain `init`
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decreased in utility.
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SPARSE CHECKOUT
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---------------
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EXAMPLES
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--------
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`git sparse-checkout set MY/DIR1 SUB/DIR2`::
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Change to a sparse checkout with all files (at any depth) under
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MY/DIR1/ and SUB/DIR2/ present in the working copy (plus all
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files immediately under MY/ and SUB/ and the toplevel
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directory). If already in a sparse checkout, change which files
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are present in the working copy to this new selection. Note
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that this command will also delete all ignored files in any
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directory that no longer has either tracked or
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non-ignored-untracked files present.
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`git sparse-checkout disable`::
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Repopulate the working directory with all files, disabling sparse
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checkouts.
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`git sparse-checkout add SOME/DIR/ECTORY`::
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Add all files under SOME/DIR/ECTORY/ (at any depth) to the
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sparse checkout, as well as all files immediately under
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SOME/DIR/ and immediately under SOME/. Must already be in a
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sparse checkout before using this command.
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`git sparse-checkout reapply`::
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It is possible for commands to update the working tree in a
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way that does not respect the selected sparsity directories.
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This can come from tools external to Git writing files, or
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even affect Git commands because of either special cases (such
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as hitting conflicts when merging/rebasing), or because some
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commands didn't fully support sparse checkouts (e.g. the old
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`recursive` merge backend had only limited support). This
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command reapplies the existing sparse directory specifications
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to make the working directory match.
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INTERNALS -- SPARSE CHECKOUT
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----------------------------
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"Sparse checkout" allows populating the working directory sparsely. It
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uses the skip-worktree bit (see linkgit:git-update-index[1]) to tell Git
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@ -155,31 +190,133 @@ directory, it updates the skip-worktree bits in the index based
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on this file. The files matching the patterns in the file will
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appear in the working directory, and the rest will not.
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To enable the sparse-checkout feature, run `git sparse-checkout set` to
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set the patterns you want to use.
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INTERNALS -- NON-CONE PROBLEMS
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------------------------------
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To repopulate the working directory with all files, use the
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`git sparse-checkout disable` command.
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The `$GIT_DIR/info/sparse-checkout` file populated by the `set` and
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`add` subcommands is defined to be a bunch of patterns (one per line)
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using the same syntax as `.gitignore` files. In cone mode, these
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patterns are restricted to matching directories (and users only ever
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need supply or see directory names), while in non-cone mode any
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gitignore-style pattern is permitted. Using the full gitignore-style
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patterns in non-cone mode has a number of shortcomings:
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* Fundamentally, it makes various worktree-updating processes (pull,
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merge, rebase, switch, reset, checkout, etc.) require O(N*M) pattern
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matches, where N is the number of patterns and M is the number of
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paths in the index. This scales poorly.
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* Avoiding the scaling issue has to be done via limiting the number
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of patterns via specifying leading directory name or glob.
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* Passing globs on the command line is error-prone as users may
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forget to quote the glob, causing the shell to expand it into all
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matching files and pass them all individually along to
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sparse-checkout set/add. While this could also be a problem with
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e.g. "git grep -- *.c", mistakes with grep/log/status appear in
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the immediate output. With sparse-checkout, the mistake gets
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recorded at the time the sparse-checkout command is run and might
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not be problematic until the user later switches branches or rebases
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or merges, thus putting a delay between the user's error and when
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they have a chance to catch/notice it.
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* Related to the previous item, sparse-checkout has an 'add'
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subcommand but no 'remove' subcommand. Even if a 'remove'
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subcommand were added, undoing an accidental unquoted glob runs
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the risk of "removing too much", as it may remove entries that had
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been included before the accidental add.
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* Non-cone mode uses gitignore-style patterns to select what to
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*include* (with the exception of negated patterns), while
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.gitignore files use gitignore-style patterns to select what to
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*exclude* (with the exception of negated patterns). The
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documentation on gitignore-style patterns usually does not talk in
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terms of matching or non-matching, but on what the user wants to
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"exclude". This can cause confusion for users trying to learn how
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to specify sparse-checkout patterns to get their desired behavior.
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* Every other git subcommand that wants to provide "special path
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pattern matching" of some sort uses pathspecs, but non-cone mode
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for sparse-checkout uses gitignore patterns, which feels
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inconsistent.
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* It has edge cases where the "right" behavior is unclear. Two examples:
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First, two users are in a subdirectory, and the first runs
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git sparse-checkout set '/toplevel-dir/*.c'
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while the second runs
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git sparse-checkout set relative-dir
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Should those arguments be transliterated into
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current/subdirectory/toplevel-dir/*.c
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and
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current/subdirectory/relative-dir
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before inserting into the sparse-checkout file? The user who typed
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the first command is probably aware that arguments to set/add are
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supposed to be patterns in non-cone mode, and probably would not be
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happy with such a transliteration. However, many gitignore-style
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patterns are just paths, which might be what the user who typed the
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second command was thinking, and they'd be upset if their argument
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wasn't transliterated.
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Second, what should bash-completion complete on for set/add commands
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for non-cone users? If it suggests paths, is it exacerbating the
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problem above? Also, if it suggests paths, what if the user has a
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file or directory that begins with either a '!' or '#' or has a '*',
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'\', '?', '[', or ']' in its name? And if it suggests paths, will
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it complete "/pro" to "/proc" (in the root filesytem) rather than to
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"/progress.txt" in the current directory? (Note that users are
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likely to want to start paths with a leading '/' in non-cone mode,
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for the same reason that .gitignore files often have one.)
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Completing on files or directories might give nasty surprises in
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all these cases.
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* The excessive flexibility made other extensions essentially
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impractical. `--sparse-index` is likely impossible in non-cone
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mode; even if it is somehow feasible, it would have been far more
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work to implement and may have been too slow in practice. Some
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ideas for adding coupling between partial clones and sparse
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checkouts are only practical with a more restricted set of paths
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as well.
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For all these reasons, non-cone mode is deprecated. Please switch to
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using cone mode.
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FULL PATTERN SET
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----------------
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INTERNALS -- CONE MODE HANDLING
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-------------------------------
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By default, the sparse-checkout file uses the same syntax as `.gitignore`
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files.
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The "cone mode", which is the default, lets you specify only what
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directories to include. For any directory specified, all paths below
|
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that directory will be included, and any paths immediately under
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leading directories (including the toplevel directory) will also be
|
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included. Thus, if you specified the directory
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Documentation/technical/
|
||||
then your sparse checkout would contain:
|
||||
|
||||
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`:
|
||||
* all files in the toplevel-directory
|
||||
* all files immediately under Documentation/
|
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* all files at any depth under Documentation/technical/
|
||||
|
||||
----------------
|
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/*
|
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!unwanted
|
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----------------
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Also, in cone mode, even if no directories are specified, then the
|
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files in the toplevel directory will be included.
|
||||
|
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When changing the sparse-checkout patterns in cone mode, Git will inspect each
|
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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.
|
||||
|
||||
|
||||
CONE PATTERN SET
|
||||
----------------
|
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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
|
||||
@ -187,32 +324,62 @@ 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.
|
||||
|
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The accepted patterns in the cone pattern set are:
|
||||
The sparse-checkout file uses the same syntax as `.gitignore` files;
|
||||
see linkgit: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 linkgit: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.
|
||||
|
||||
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:
|
||||
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 in root, but nothing two levels below root."
|
||||
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 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
|
||||
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
|
||||
|
||||
----------------
|
||||
/*
|
||||
@ -227,14 +394,18 @@ patterns. The resulting sparse-checkout file is now
|
||||
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.
|
||||
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, 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:
|
||||
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
|
||||
@ -246,19 +417,9 @@ 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.
|
||||
|
||||
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.
|
||||
|
||||
|
||||
SUBMODULES
|
||||
----------
|
||||
INTERNALS -- SUBMODULES
|
||||
-----------------------
|
||||
|
||||
If your repository contains one or more submodules, then submodules
|
||||
are populated based on interactions with the `git submodule` command.
|
||||
|
||||
Reference in New Issue
Block a user