[PATCH] merge-file: fix BUG when --object-id is used in a worktree
- From
Mathias Rav <m@git.strova.dk>
- Date
- Mar 10, 2026, 11:46 UTC
- Message-ID
- <86e5c9f7-cd99-4c4f-a852-f3b1ada53722@app.fastmail.com>
The `--object-id` option was added in commit e1068f0ad4 ("merge-file: add an option to process object IDs", 2023-11-01) together with a call to setup_git_directory() to avoid crashing when run outside a repository.
However, the call to setup_git_directory() is redundant when run inside a repository, as merge-file runs with RUN_SETUP_GENTLY, so the repository has already been set up. The redundant call is harmless when worktrees are not used, but when run inside a worktree, the repo_set_gitdir() function ends up being called twice.
Calling repo_set_gitdir() used to be silently accepted, but commit 2816b748e5 ("odb: handle changing a repository's commondir", 2025-11-19) changed this to a BUG in repository.c with the error message: "cannot reinitialize an already-initialized object directory".
Guard the call to setup_git_directory() behind a repo pointer check, to ensure that we continue to give the correct "not a git repo" error whilst avoiding the BUG when running inside a worktree.
Signed-off-by: Mathias Rav <m@git.strova.dk> --- builtin/merge-file.c | 4 ++-- t/t6403-merge-file.sh | 9 +++++++++ 2 files changed, 11 insertions(+), 2 deletions(-)
diff --git a/builtin/merge-file.c b/builtin/merge-file.c index 46775d0c79..a8768c6e0c 100644 --- a/builtin/merge-file.c +++ b/builtin/merge-file.c @@ -60,7 +60,7 @@ static int diff_algorithm_cb(const struct option *opt, int cmd_merge_file(int argc, const char **argv, const char *prefix, - struct repository *repo UNUSED) + struct repository *repo) { const char *names[3] = { 0 }; mmfile_t mmfs[3] = { 0 }; @@ -110,7 +110,7 @@ int cmd_merge_file(int argc, return error_errno("failed to redirect stderr to /dev/null"); } - if (object_id) + if (object_id && !repo) setup_git_directory(); for (i = 0; i < 3; i++) { diff --git a/t/t6403-merge-file.sh b/t/t6403-merge-file.sh index 06ab4d7aed..60cc43775f 100755 --- a/t/t6403-merge-file.sh +++ b/t/t6403-merge-file.sh @@ -506,6 +506,15 @@ test_expect_success '--object-id fails without repository' ' grep "not a git repository" err ' +test_expect_success 'run inside worktree with --object-id' ' + empty="$(test_oid empty_blob)" && + git worktree add work && + (cd work && git merge-file --object-id $empty $empty $empty) >actual && + git worktree remove work && + git merge-file --object-id $empty $empty $empty >expected && + test_cmp actual expected +' + test_expect_success 'merging C files with "myers" diff algorithm creates some spurious conflicts' ' cat >expect.c <<-\EOF && int g(size_t u)
-- 2.53.0