@matheusbsbs / matheus-bagliano / commits / 57246b7c62

merge-file: fix BUG when --object-id is used in a worktree

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 linked worktrees are not used, but in a linked 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 redundant 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 in a linked worktree. Signed-off-by: Mathias Rav <m@git.strova.dk> Signed-off-by: Junio C Hamano <gitster@pobox.com>

Mathias Rav committed Mar 11, 2026 at 06:44 UTC 57246b7c626c18bad5f7a36b9479dea58b73242d

2 files changed +12 -2

builtin/merge-file.c

+3 -2

@@ -60,7 +60,7 @@ static int diff_algorithm_cb(const struct option *opt,

60 int cmd_merge_file(int argc,

61 const char **argv,

62 const char *prefix,

63 - struct repository *repo UNUSED)

63 + struct repository *repo)

64 {

65 const char *names[3] = { 0 };

66 mmfile_t mmfs[3] = { 0 };

@@ -110,7 +110,8 @@ int cmd_merge_file(int argc,

110 return error_errno("failed to redirect stderr to /dev/null");

111 }

112

113 - if (object_id)

113 + if (!repo && object_id)

114 + /* emit the correct "not a git repo" error in this case */

115 setup_git_directory();

116

117 for (i = 0; i < 3; i++) {

t/t6403-merge-file.sh

@@ -506,6 +506,15 @@ test_expect_success '--object-id fails without repository' '

506 grep "not a git repository" err

507 '

508

509 +test_expect_success 'run in a linked worktree with --object-id' '

510 + empty="$(test_oid empty_blob)" &&

511 + git worktree add work &&

512 + git -C work merge-file --object-id $empty $empty $empty >actual &&

513 + git worktree remove work &&

514 + git merge-file --object-id $empty $empty $empty >expected &&

515 + test_cmp actual expected

516 +'

517 +

518 test_expect_success 'merging C files with "myers" diff algorithm creates some spurious conflicts' '

519 cat >expect.c <<-\EOF &&

520 int g(size_t u)