Re: [PATCH v5 3/4] refs: allow reference location in refstorage config

Patrick Steinhardt [off-list ref] writes:

On Mon, Feb 09, 2026 at 04:58:20PM +0100, Karthik Nayak wrote:

quoted

The 'extensions.refStorage' config is used to specify the reference
backend for a given repository. Both the 'files' and 'reftable' backends
utilize the $GIT_DIR as the reference folder by default in
`get_main_ref_store()`.

Since the reference backends are pluggable, this means that they could
work with out-of-tree reference directories too. Extend the 'refStorage'
config to also support taking an URI input, where users can specify the
reference backend and the location.

Add the required changes to obtain and propagate this value to the
individual backends also add the necessary documentation and tests.

This reads as if this should have been two sentences.

Yeah, let me split it up.

quoted

diff --git a/builtin/worktree.c b/builtin/worktree.c
index fbdaf2eb2e..94480be5c4 100644
--- a/builtin/worktree.c
+++ b/builtin/worktree.c

@@ -425,6 +425,39 @@ static int make_worktree_orphan(const char * ref, const struct add_opts *opts,
 	return run_command(&cp);
 }

+/*
+ * References for worktress are generally stored in '$GIT_DIR/worktrees/<wt_id>'.

s/worktress/worktrees/

Oops.

quoted

+for to_format in $ref_formats
+do
+	if test "$from_format" = "$to_format"
+	then
+		continue
+	fi
+
+
+	for dir in "$(pwd)/repo/.git" "./"

As "./" is a relative directory I expect it to be resolved relative to
"$GIT_DIR", right?

Yup the './' is relative to the '$GIT_DIR'. It can be changed to '.', so
I'll do that and add a comment. So we do both

  BACKEND_PATH='/home/karthik/code/git/build/test-output/trash
directory.t1423-ref-backend/repo/.git/ref_migration.ZnKNpg'

and

  BACKEND_PATH=./ref_migration.BFyK5k

Also, I don't see any tests that create the ref
directory outside of the repository. Should we maybe add one?

Yeah, let me add that test.

quoted

+	do
+
+		test_expect_success "$read from $to_format backend, $dir dir" '
+			test_when_finished "rm -rf repo" &&
+			git init --ref-format=$from_format repo &&
+			(
+				cd repo &&
+				test_commit 1 &&
+				test_commit 2 &&
+				test_commit 3 &&
+
+				git refs migrate --dry-run --ref-format=$to_format >out &&

Okay, we do the migration, but with "--dry-run". This should result in a
temporary staging directory, which is in fact somewhat interesting given
that "to_format" can now contain a payload. I assume it wouldn't have an
impact if such a payload was set here?

It cannot, the 'git refs migrate' command parses the argument provided
to '--ref-format' as a reference-backend.

quoted

+				BACKEND_PATH="$dir/$(sed "s/.* ${SQ}.git\/\(.*\)${SQ}/\1/" out)" &&

Hm. I have no idea what this is doing :)

It extracts out the name of the dry-run folder created by 'git refs
migrate'. We append the $dir to it, which could be the absolute path or
the relative path.

quoted

+				test_refs_backend . $from_format "$to_format://$BACKEND_PATH" "$method"
+			)
+		'

In general I think it would be sensible to also have a couple tests here
that exercise specific formats directly. Like:

  - Are the files created in the right spots for the files and reftable
    backend with a specific backend?

  - Does `git refs migrate` know to write the files into the correct
    location in case "--dry-run" wasn't passed?

Will add tests for the following too.

  - Does git-init(1) and git-clone(1) initialize the refstore in a
    different location as expected?

Well so this only works when there is a reference store already
existing. I thought I had explicitly called this out, but doesn't seem
to be the case. I think it would actually make sense that it also works
with creation. So let me look into that.

  - Does creating a worktree work?

This is currently already tested.

Patrick