Re: [PATCH v4 3/4] ref-filter: name the worktree of a branch being rebased or bisected

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

Hi Jasper

On 02/11/2026 18:29, Jasper Mayone wrote:
> %(worktreepath) gives the worktree that has a branch checked out, and
> "git branch" uses it to mark such branches with "+". It only looks at
> the HEAD of each worktree, so while a worktree is rebasing or
> bisecting a branch, its HEAD is detached and the branch shows no
> worktree at all.
> 
> The rest of Git already treats that branch as checked out: "git
> worktree add" and "git branch -d" refuse it, because finishing the
> rebase or bisect will check it out again. But no command shows which
> worktree is working on the branch: "git worktree list" shows such a
> worktree as "(detached HEAD)", and %(worktreepath) is empty.
> 
> branch.c already knows the answer, as prepare_checked_out_branches()
> records the branch that each worktree has checked out, is rebasing or
> is bisecting. Add branch_checked_out_worktree() to look a branch up in
> that list, and use it for %(worktreepath) in place of the map that
> ref-filter.c builds from the HEAD of each worktree.
> 
> The new function skips the branches that "rebase --update-refs" will
> update. branch_checked_out() includes them, so that they cannot be
> checked out or deleted during the rebase, but the worktree that runs
> the rebase has not checked them out. %(worktreepath) therefore stays
> empty for them, unlike branch_checked_out().
> 
> This also changes the result for a bare repository: its HEAD names a
> branch, and %(worktreepath) used to give the path of the bare
> repository for that branch. "git branch" in a linked worktree marked
> the branch with "+", although no worktree has it checked out and "git
> worktree add" lets you check it out. prepare_checked_out_branches()
> skips bare repositories, so %(worktreepath) is now empty for that
> branch and "git branch" no longer marks it.

We now document the change in behavior - good.

> diff --git a/branch.c b/branch.c
> index 5bb1c28915..8dab72d857 100644
> --- a/branch.c
> +++ b/branch.c
> @@ -485,6 +485,19 @@ const char *branch_checked_out(const char *refname)
>   	return strmap_get(&current_checked_out_branches, refname);
>   }
>   
> +const char *branch_checked_out_worktree(const char *refname)
> +{
> +	const char *path = NULL;
> +
> +	prepare_checked_out_branches();
> +	for (size_t i = 0; i < checked_out_branches_nr; i++) {
> +		if (checked_out_branches[i].kind != BRANCH_CHECKOUT_KIND_UPDATE_REF &&
> +		    !strcmp(refname, checked_out_branches[i].refname))
> +			path = checked_out_branches[i].path;
> +	}

Iterating over all the worktrees for every ref is going to be slower 
than it needs to be. As I said in [1] we should use a hash map to map 
branch names to the worktree where they are checked out. That is also 
what the existing ref-filter code does.

Then we can add a function to get the worktree path where a branch is 
checked out and call that from the ref-filter code.

Thanks

Phillip

> +	return path;
> +}
> +
>   const char *branch_bisecting(const char *refname)
>   {
>   	prepare_checked_out_branches();
> diff --git a/branch.h b/branch.h
> index 95b2431f24..60cb92a3e4 100644
> --- a/branch.h
> +++ b/branch.h
> @@ -106,6 +106,15 @@ void create_branches_recursively(struct repository *r, const char *name,
>    */
>   const char *branch_checked_out(const char *refname);
>   
> +/*
> + * If a worktree has the branch 'refname' checked out, or is rebasing or
> + * bisecting it, return the path of that worktree, or of the last one if
> + * there are more. Otherwise return NULL. Unlike branch_checked_out(),
> + * this ignores the branches that "git rebase --update-refs" will
> + * update, because no worktree has them checked out.
> + */
> +const char *branch_checked_out_worktree(const char *refname);
> +
>   /*
>    * If the branch at 'refname' is currently used for bisecting in a
>    * worktree, then return the path to that worktree.
> diff --git a/ref-filter.c b/ref-filter.c
> index bdf54f6f59..b636e56199 100644
> --- a/ref-filter.c
> +++ b/ref-filter.c
> @@ -2,6 +2,7 @@
>   #define DISABLE_SIGN_COMPARE_WARNINGS
>   
>   #include "git-compat-util.h"
> +#include "branch.h"
>   #include "environment.h"
>   #include "gettext.h"
>   #include "config.h"
> @@ -95,30 +96,6 @@ static struct expand_data {
>   	struct object_info info;
>   } oi, oi_deref;
>   
> -struct ref_to_worktree_entry {
> -	struct hashmap_entry ent;
> -	struct worktree *wt; /* key is wt->head_ref */
> -};
> -
> -static int ref_to_worktree_map_cmpfnc(const void *lookupdata UNUSED,
> -				      const struct hashmap_entry *eptr,
> -				      const struct hashmap_entry *kptr,
> -				      const void *keydata_aka_refname)
> -{
> -	const struct ref_to_worktree_entry *e, *k;
> -
> -	e = container_of(eptr, const struct ref_to_worktree_entry, ent);
> -	k = container_of(kptr, const struct ref_to_worktree_entry, ent);
> -
> -	return strcmp(e->wt->head_ref,
> -		keydata_aka_refname ? keydata_aka_refname : k->wt->head_ref);
> -}
> -
> -static struct ref_to_worktree_map {
> -	struct hashmap map;
> -	struct worktree **worktrees;
> -} ref_to_worktree_map;
> -
>   /*
>    * The enum atom_type is used as the index of valid_atom array.
>    * In the atom parsing stage, it will be passed to used_atom.atom_type
> @@ -2380,49 +2357,11 @@ static int get_object(struct ref_array_item *ref, int deref,
>   	return ret;
>   }
>   
> -static void populate_worktree_map(struct hashmap *map, struct worktree **worktrees)
> -{
> -	int i;
> -
> -	for (i = 0; worktrees[i]; i++) {
> -		if (worktrees[i]->head_ref) {
> -			struct ref_to_worktree_entry *entry;
> -			entry = xmalloc(sizeof(*entry));
> -			entry->wt = worktrees[i];
> -			hashmap_entry_init(&entry->ent,
> -					strhash(worktrees[i]->head_ref));
> -
> -			hashmap_add(map, &entry->ent);
> -		}
> -	}
> -}
> -
> -static void lazy_init_worktree_map(void)
> -{
> -	if (ref_to_worktree_map.worktrees)
> -		return;
> -
> -	ref_to_worktree_map.worktrees = get_worktrees(the_repository);
> -	hashmap_init(&(ref_to_worktree_map.map), ref_to_worktree_map_cmpfnc, NULL, 0);
> -	populate_worktree_map(&(ref_to_worktree_map.map), ref_to_worktree_map.worktrees);
> -}
> -
>   static char *get_worktree_path(const struct ref_array_item *ref)
>   {
> -	struct hashmap_entry entry, *e;
> -	struct ref_to_worktree_entry *lookup_result;
> +	const char *path = branch_checked_out_worktree(ref->refname);
>   
> -	lazy_init_worktree_map();
> -
> -	hashmap_entry_init(&entry, strhash(ref->refname));
> -	e = hashmap_get(&(ref_to_worktree_map.map), &entry, ref->refname);
> -
> -	if (!e)
> -		return xstrdup("");
> -
> -	lookup_result = container_of(e, struct ref_to_worktree_entry, ent);
> -
> -	return xstrdup(lookup_result->wt->path);
> +	return xstrdup(path ? path : "");
>   }
>   
>   /*
> @@ -3195,13 +3134,6 @@ void ref_array_clear(struct ref_array *array)
>   	FREE_AND_NULL(used_atom);
>   	used_atom_cnt = 0;
>   
> -	if (ref_to_worktree_map.worktrees) {
> -		hashmap_clear_and_free(&(ref_to_worktree_map.map),
> -					struct ref_to_worktree_entry, ent);
> -		free_worktrees(ref_to_worktree_map.worktrees);
> -		ref_to_worktree_map.worktrees = NULL;
> -	}
> -
>   	FREE_AND_NULL(array->counts);
>   }
>   
> diff --git a/t/t3203-branch-output.sh b/t/t3203-branch-output.sh
> index 7c44186341..debfac5f26 100755
> --- a/t/t3203-branch-output.sh
> +++ b/t/t3203-branch-output.sh
> @@ -442,6 +442,35 @@ test_expect_success 'worktree colors correct' '
>   	test_cmp expect actual
>   '
>   
> +test_expect_success 'branch being rebased in a worktree is marked' '
> +	test_when_finished "git -C rebase_dir rebase --abort; rm -rf rebase_dir; git worktree prune; git branch -D rebasing" &&
> +	git worktree add -b rebasing rebase_dir branch-two &&
> +	(
> +		cd rebase_dir &&
> +		git commit --allow-empty -m rebase-me &&
> +		test_must_fail git rebase -f -x false HEAD~1 &&
> +		test_must_fail git symbolic-ref -q HEAD
> +	) &&
> +	git branch --list rebasing >actual &&
> +	echo "+ rebasing" >expect &&
> +	test_cmp expect actual
> +'
> +
> +test_expect_success 'branch being bisected in a worktree is marked' '
> +	test_when_finished "git -C bisect_dir bisect reset; rm -rf bisect_dir; git worktree prune; git branch -D bisecting" &&
> +	git worktree add -b bisecting bisect_dir branch-two &&
> +	(
> +		cd bisect_dir &&
> +		git commit --allow-empty -m bisect-one &&
> +		git commit --allow-empty -m bisect-two &&
> +		git bisect start HEAD HEAD~2 &&
> +		test_must_fail git symbolic-ref -q HEAD
> +	) &&
> +	git branch --list bisecting >actual &&
> +	echo "+ bisecting" >expect &&
> +	test_cmp expect actual
> +'
> +
>   test_expect_success "set up color tests" '
>   	echo "<RED>main<RESET>" >expect.color &&
>   	echo "main" >expect.bare &&
> diff --git a/t/t6302-for-each-ref-filter.sh b/t/t6302-for-each-ref-filter.sh
> index 7f060d97bf..317ed6f6cd 100755
> --- a/t/t6302-for-each-ref-filter.sh
> +++ b/t/t6302-for-each-ref-filter.sh
> @@ -3,6 +3,7 @@
>   test_description='test for-each-refs usage of ref-filter APIs'
>   
>   . ./test-lib.sh
> +. "$TEST_DIRECTORY"/lib-rebase.sh
>   . "$TEST_DIRECTORY"/lib-gpg.sh
>   
>   test_expect_success 'setup some history and refs' '
> @@ -541,6 +542,81 @@ test_expect_success 'validate worktree atom' '
>   	test_cmp expect actual
>   '
>   
> +test_expect_success 'worktree atom names a worktree rebasing the branch' '
> +	test_when_finished "git -C rebasing rebase --abort; rm -rf rebasing; git worktree prune; git branch -D rebasing" &&
> +	git worktree add -b rebasing rebasing main &&
> +	git -C rebasing commit --allow-empty -m rebase-me &&
> +	test_must_fail git -C rebasing rebase -f -x false main &&
> +	test_must_fail git -C rebasing symbolic-ref -q HEAD &&
> +	echo "$(pwd)/rebasing" >expect &&
> +	git for-each-ref --format="%(worktreepath)" refs/heads/rebasing >actual &&
> +	test_cmp expect actual
> +'
> +
> +test_expect_success 'worktree atom names a worktree bisecting the branch' '
> +	test_when_finished "git -C bisecting bisect reset; rm -rf bisecting; git worktree prune; git branch -D bisecting" &&
> +	git worktree add -b bisecting bisecting main &&
> +	git -C bisecting commit --allow-empty -m bisect-one &&
> +	git -C bisecting commit --allow-empty -m bisect-two &&
> +	git -C bisecting bisect start HEAD main &&
> +	test_must_fail git -C bisecting symbolic-ref -q HEAD &&
> +	echo "$(pwd)/bisecting" >expect &&
> +	git for-each-ref --format="%(worktreepath)" refs/heads/bisecting >actual &&
> +	test_cmp expect actual
> +'
> +
> +test_expect_success 'worktree atom with an interactive rebase stopped at edit' '
> +	test_when_finished "git -C editing rebase --abort; rm -rf editing; git worktree prune; git branch -D editing" &&
> +	git worktree add -b editing editing main &&
> +	git -C editing commit --allow-empty -m edit-me &&
> +	(
> +		set_fake_editor &&
> +		FAKE_LINES="edit 1" git -C editing rebase -i --keep-empty HEAD~1
> +	) &&
> +	test_must_fail git -C editing symbolic-ref -q HEAD &&
> +	echo "$(pwd)/editing" >expect &&
> +	git for-each-ref --format="%(worktreepath)" refs/heads/editing >actual &&
> +	test_cmp expect actual
> +'
> +
> +test_expect_success 'worktree atom ignores branches rebase --update-refs will move' '
> +	test_when_finished "git -C updating rebase --abort; rm -rf updating; git worktree prune; git branch -D updating mid" &&
> +	git worktree add -b updating updating main &&
> +	git -C updating commit --allow-empty -m one &&
> +	git -C updating branch mid &&
> +	git -C updating commit --allow-empty -m two &&
> +	test_must_fail git -C updating rebase -f --update-refs -x false main &&
> +	git for-each-ref --format="%(refname:short) [%(worktreepath)]" \
> +		refs/heads/updating refs/heads/mid >actual &&
> +	cat >expect <<-EOF &&
> +	mid []
> +	updating [$(pwd)/updating]
> +	EOF
> +	test_cmp expect actual
> +'
> +
> +test_expect_success 'worktree atom ignores a rebase of a detached HEAD' '
> +	test_when_finished "git -C detached-rebase rebase --abort; rm -rf detached-rebase; git worktree prune" &&
> +	git worktree add --detach detached-rebase main &&
> +	git -C detached-rebase commit --allow-empty -m detached &&
> +	test_must_fail git -C detached-rebase rebase -f -x false main &&
> +	git for-each-ref --format="%(worktreepath)" refs/heads/ >actual &&
> +	test_grep ! detached-rebase actual
> +'
> +
> +test_expect_success 'worktree atom ignores the HEAD of a bare repository' '
> +	test_when_finished "rm -rf bare.git bare-wt" &&
> +	git clone --bare . bare.git &&
> +	git -C bare.git symbolic-ref HEAD refs/heads/main &&
> +	git -C bare.git worktree add --detach ../bare-wt main &&
> +	git -C bare.git for-each-ref --format="%(worktreepath)" refs/heads/main >actual &&
> +	echo >expect &&
> +	test_cmp expect actual &&
> +	git -C bare-wt branch --list main >actual &&
> +	echo "  main" >expect &&
> +	test_cmp expect actual
> +'
> +
>   test_expect_success 'start after with empty value' '
>   	cat >expect <<-\EOF &&
>   	refs/heads/main