Re: [PATCH] dir: use per-worktree repository ignore patterns upon request

[Phillip Wood <phillip.wood123@gmail.com>]

Hi Ben

On 24/04/2026 18:09, D. Ben Knoble wrote:
> Today we have $GIT_DIR/info/exclude for the main worktree, but $(git
> rev-parse --git-dir)/info/exclude for secondary worktrees does not
> actually contribute to ignore specs; instead, secondary worktrees also
> use $GIT_COMMON_DIR/info/exclude.

Sharing the same set of exclude patterns between all worktrees seems 
like a reasonable thing to do - it would be a pain to have to populate 
them every time a new worktree was created.

	git rev-parse --git-path info/exclude

always returns the correct path because it uses repo_git_path() which 
knows whether a particular path is per-worktree or resides under 
$GIT_COMMON_DIR. It is best to avoid constructing paths manually using 
"git rev-parse --git-dir"

> Some users may prefer each worktree use its own ignore file; some may
> prefer both; some may prefer the current behavior.

This sounds quite hypothetical - do we have a concrete use case for 
per-worktree exclude files?

If there is a use for per-worktree excludes it would be much better to 
use a different path such as "info.worktree/exclude" so that the main 
worktree can have both shared and per-worktree excludes. We could use 
"exclude.worktree" like "config.worktree" but then we'd be in danger of 
adding new ".worktree" files in the future if we want to add 
per-worktree versions of other files that live under "info/"

Thanks

Phillip

> Add, test, and document extensions.worktreeIgnore that controls which
> set of ignore files to use for worktrees.
> 
> Signed-off-by: D. Ben Knoble <ben.knoble+github@gmail.com>
> ---
> 
> Notes (benknoble/commits):
>      Discussed briefly at https://lore.kernel.org/git/CALnO6CCXmA+ATT7CuyWkU6P8qmLCCpMi5Ppr1c78s0heznpVyw@mail.gmail.com/T
> 
>      This is based on next (4f69b47b94 (Merge branch 'ps/test-set-e-clean' into
>      next, 2026-04-23)) but cleanly applies to master (94f057755b (Git 2.54,
>      2026-04-19)) and seen (50541634cb (Merge branch
>      'js/parseopt-subcommand-autocorrection' into seen, 2026-04-23)).
> 
>   Documentation/config/extensions.adoc |  7 ++++
>   Documentation/git-worktree.adoc      |  3 ++
>   Documentation/gitignore.adoc         |  6 ++--
>   dir.c                                | 48 +++++++++++++++++++++++---
>   t/meson.build                        |  1 +
>   t/t2408-worktree-ignore.sh           | 50 ++++++++++++++++++++++++++++
>   6 files changed, 109 insertions(+), 6 deletions(-)
>   create mode 100755 t/t2408-worktree-ignore.sh
> 
> diff --git a/Documentation/config/extensions.adoc b/Documentation/config/extensions.adoc
> index be6678bb5b..5bfb06a54b 100644
> --- a/Documentation/config/extensions.adoc
> +++ b/Documentation/config/extensions.adoc
> @@ -148,3 +148,10 @@ details.
>   +
>   For historical reasons, this extension is respected regardless of the
>   `core.repositoryFormatVersion` setting.
> +
> +worktreeIgnore:::
> +	If enabled, then worktrees will load per-repository ignore files from
> +	`$GIT_DIR/info/exclude` (that is,
> +	`$GIT_COMMON_DIR/worktrees/<id>/info/exclude`). If set to `merge`, then
> +	both `$GIT_COMMON_DIR/info/exclude` and `$GIT_DIR/info/exclude` are
> +	used.
> diff --git a/Documentation/git-worktree.adoc b/Documentation/git-worktree.adoc
> index fbf8426cd9..611c1e06b0 100644
> --- a/Documentation/git-worktree.adoc
> +++ b/Documentation/git-worktree.adoc
> @@ -412,6 +412,9 @@ linkgit:gitrepository-layout[5] for details.
>   When `extensions.worktreeConfig` is enabled, the config file
>   `.git/worktrees/<id>/config.worktree` is read after `.git/config` is.
>   
> +See `extensions.worktreeIgnore` in linkgit:git-config[1] to control how
> +per-repository ignore files are found in worktrees.
> +
>   LIST OUTPUT FORMAT
>   ------------------
>   The `worktree list` command has two output formats. The default format shows the
> diff --git a/Documentation/gitignore.adoc b/Documentation/gitignore.adoc
> index a3d24e5c34..d6976a44e4 100644
> --- a/Documentation/gitignore.adoc
> +++ b/Documentation/gitignore.adoc
> @@ -7,7 +7,7 @@ gitignore - Specifies intentionally untracked files to ignore
>   
>   SYNOPSIS
>   --------
> -$XDG_CONFIG_HOME/git/ignore, $GIT_DIR/info/exclude, .gitignore
> +$XDG_CONFIG_HOME/git/ignore, $GIT_COMMON_DIR/info/exclude, .gitignore
>   
>   DESCRIPTION
>   -----------
> @@ -34,7 +34,9 @@ precedence, the last matching pattern decides the outcome):
>      includes such `.gitignore` files in its repository, containing patterns for
>      files generated as part of the project build.
>   
> - * Patterns read from `$GIT_DIR/info/exclude`.
> + * Patterns read from `$GIT_COMMON_DIR/info/exclude`. (See
> +   `extensions.worktreeIgnore` in linkgit:git-config[1] to change how this
> +   applies to worktrees.)
>   
>    * Patterns read from the file specified by the configuration
>      variable `core.excludesFile`.
> diff --git a/dir.c b/dir.c
> index fcb8f6dd2a..9592eb0062 100644
> --- a/dir.c
> +++ b/dir.c
> @@ -36,6 +36,7 @@
>   #include "trace2.h"
>   #include "tree.h"
>   #include "hex.h"
> +#include "worktree.h"
>   
>    /*
>     * The maximum size of a pattern/exclude file. If the file exceeds this size
> @@ -3478,6 +3479,23 @@ int remove_dir_recursively(struct strbuf *path, int flag)
>   }
>   
>   static GIT_PATH_FUNC(git_path_info_exclude, "info/exclude")
> +static const char *git_worktree_info_exclude(void)
> +{
> +	static const char *ret;
> +	if (!ret)
> +	{
> +		const struct worktree *wt = get_worktree_from_repository(the_repository);
> +		ret = worktree_git_path(wt, "info/exclude");
> +	}
> +	return ret;
> +}
> +
> +static void standard_exclude_from_info(const char *path, struct dir_struct *dir)
> +{
> +	struct oid_stat *oid_stat = dir->untracked ? &dir->internal.ss_info_exclude : NULL;
> +	if (!access_or_warn(path, R_OK, 0))
> +		add_patterns_from_file_1(dir, path, oid_stat);
> +}
>   
>   void setup_standard_excludes(struct dir_struct *dir)
>   {
> @@ -3492,10 +3510,32 @@ void setup_standard_excludes(struct dir_struct *dir)
>   
>   	/* per repository user preference */
>   	if (startup_info->have_repository) {
> -		const char *path = git_path_info_exclude();
> -		if (!access_or_warn(path, R_OK, 0))
> -			add_patterns_from_file_1(dir, path,
> -						 dir->untracked ? &dir->internal.ss_info_exclude : NULL);
> +		/* extensions.worktreeIgnore determines which includes we add */
> +		const char *wt_ignore;
> +		int do_wt_ignore;
> +		if (repo_config_get_value(the_repository,
> +					  "extensions.worktreeIgnore",
> +					  &wt_ignore)) {
> +			/* unset: use main/.git/info/exclude */
> +			standard_exclude_from_info(git_path_info_exclude(), dir);
> +			return;
> +		}
> +		do_wt_ignore = git_parse_maybe_bool(wt_ignore);
> +		if (!do_wt_ignore) {
> +			/* false: as above */
> +			standard_exclude_from_info(git_path_info_exclude(), dir);
> +		} else if (do_wt_ignore > 0 || !strcmp(wt_ignore, "worktree")) {
> +			/* true/worktree: use worktree/.git‡/info/exclude
> +			 * ‡: resolving .git */
> +			standard_exclude_from_info(git_worktree_info_exclude(), dir);
> +		} else if (!strcmp(wt_ignore, "merge")) {
> +			/* merge both! worktree last */
> +			standard_exclude_from_info(git_path_info_exclude(), dir);
> +			standard_exclude_from_info(git_worktree_info_exclude(), dir);
> +		} else {
> +			die(_("invalid value for '%s': '%s'"),
> +			      "extensions.worktreeIgnore", wt_ignore);
> +		}
>   	}
>   }
>   
> diff --git a/t/meson.build b/t/meson.build
> index 7528e5cda5..30624b59e8 100644
> --- a/t/meson.build
> +++ b/t/meson.build
> @@ -307,6 +307,7 @@ integration_tests = [
>     't2405-worktree-submodule.sh',
>     't2406-worktree-repair.sh',
>     't2407-worktree-heads.sh',
> +  't2408-worktree-ignore.sh',
>     't2500-untracked-overwriting.sh',
>     't2501-cwd-empty.sh',
>     't3000-ls-files-others.sh',
> diff --git a/t/t2408-worktree-ignore.sh b/t/t2408-worktree-ignore.sh
> new file mode 100755
> index 0000000000..67644ddd8d
> --- /dev/null
> +++ b/t/t2408-worktree-ignore.sh
> @@ -0,0 +1,50 @@
> +#!/bin/sh
> +
> +test_description='extensions.worktreeIgnore'
> +
> +. ./test-lib.sh
> +
> +test_expect_success 'setup' '
> +	test_commit init &&
> +	git worktree add wt &&
> +	echo main >.git/info/exclude &&
> +	echo contents >main &&
> +	echo contents >wt/main &&
> +	wt_exclude="$(git -C wt rev-parse --git-dir)"/info/exclude &&
> +	mkdir -p "$(dirname "$wt_exclude")" &&
> +	echo worktree >"$wt_exclude" &&
> +	echo contents >worktree &&
> +	echo contents >wt/worktree
> +'
> +
> +test_ignore_main() {
> +	git check-ignore main &&
> +	git -C wt check-ignore main
> +}
> +
> +test_expect_success 'ignores main items by default' '
> +	test_ignore_main
> +'
> +
> +test_expect_success 'ignores main items with extensions.worktreeIgnore=no' '
> +	test_config extensions.worktreeIgnore no &&
> +	test_ignore_main
> +'
> +
> +test_expect_success 'ignores worktree items with extensions.worktreeIgnore=worktree' '
> +	test_config extensions.worktreeIgnore worktree &&
> +	git check-ignore main &&
> +	! git check-ignore worktree &&
> +	! git -C wt check-ignore main &&
> +	git -C wt check-ignore worktree
> +'
> +
> +test_expect_success 'ignores all items with extensions.worktreeIgnore=merge' '
> +	test_config extensions.worktreeIgnore merge &&
> +	git check-ignore main &&
> +	! git check-ignore worktree &&
> +	git -C wt check-ignore main &&
> +	git -C wt check-ignore worktree
> +'
> +
> +test_done
> 
> base-commit: 4f69b47b940100b02630f745a52f9d9850f122b2