[PATCH] submodule--helper absorbgitdirs: no abspaths in "Migrating git..."

["Ævar Arnfjörð Bjarmason" <avarab@gmail.com>]

Change the "Migrating git directory" messages to avoid emitting
absolute paths. We could use "old_git_dir" and "new_gitdir.buf" here
sometimes, but not in all the cases covered by these tests,
i.e. sometimes the latter will be an absolute path with a different
prefix.

So let's just strip off the common prefix of the two strings, which
handles the cases where we have nested submodules nicely. Note that
this case is different than the one in get_submodule_displaypath() in
"builtin/submodule--helper.c" handles, as we're dealing with the paths
to the two ".git" here, not worktree paths.

Before this change we had no tests at all for this "Migrating git
directory" output.

Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
---

Something I hacked up a while ago, but which I'm prompted to send in
by [1] which added a test for this output, but did so with:

	+  cat >expect.err <<-EOF &&
	+  Migrating git directory of ${SQ}sub1/nested${SQ} from
	+  ${SQ}/Users/chooglen/Code/git/t/trash directory.t7412-submodule-absorbgitdirs/sub1/nested/.git${SQ} to
	+  ${SQ}/Users/chooglen/Code/git/t/trash directory.t7412-submodule-absorbgitdirs/.git/modules/sub1/modules/nested${SQ}

:)

Let's make this message a lot less verbose, and easier to test
instead.

1. https://lore.kernel.org/git/20221109004708.97668-2-chooglen@google.com/

 submodule.c                        |  8 +++++--
 t/t7412-submodule-absorbgitdirs.sh | 36 ++++++++++++++++++++++++------
 2 files changed, 35 insertions(+), 9 deletions(-)

diff --git a/submodule.c b/submodule.c
index b958162d286..1f0032d183a 100644
--- a/submodule.c
+++ b/submodule.c
@@ -2274,6 +2274,7 @@ static void relocate_single_git_dir_into_superproject(const char *path)
 	char *old_git_dir = NULL, *real_old_git_dir = NULL, *real_new_git_dir = NULL;
 	struct strbuf new_gitdir = STRBUF_INIT;
 	const struct submodule *sub;
+	size_t off = 0;
 
 	if (submodule_uses_worktrees(path))
 		die(_("relocate_gitdir for submodule '%s' with "
@@ -2298,9 +2299,12 @@ static void relocate_single_git_dir_into_superproject(const char *path)
 		die(_("could not create directory '%s'"), new_gitdir.buf);
 	real_new_git_dir = real_pathdup(new_gitdir.buf, 1);
 
-	fprintf(stderr, _("Migrating git directory of '%s%s' from\n'%s' to\n'%s'\n"),
+	while (real_old_git_dir[off] && real_new_git_dir[off] &&
+	       real_old_git_dir[off] == real_new_git_dir[off])
+		off++;
+	fprintf(stderr, _("Migrating git directory of '%s%s' from '%s' to '%s'\n"),
 		get_super_prefix_or_empty(), path,
-		real_old_git_dir, real_new_git_dir);
+		real_old_git_dir + off, real_new_git_dir + off);
 
 	relocate_gitdir(path, real_old_git_dir, real_new_git_dir);
 
diff --git a/t/t7412-submodule-absorbgitdirs.sh b/t/t7412-submodule-absorbgitdirs.sh
index 2859695c6d2..a5cd6db7ac2 100755
--- a/t/t7412-submodule-absorbgitdirs.sh
+++ b/t/t7412-submodule-absorbgitdirs.sh
@@ -18,13 +18,19 @@ test_expect_success 'setup a real submodule' '
 '
 
 test_expect_success 'absorb the git dir' '
+	>expect &&
+	>actual &&
 	>expect.1 &&
 	>expect.2 &&
 	>actual.1 &&
 	>actual.2 &&
 	git status >expect.1 &&
 	git -C sub1 rev-parse HEAD >expect.2 &&
-	git submodule absorbgitdirs &&
+	cat >expect <<-\EOF &&
+	Migrating git directory of '\''sub1'\'' from '\''sub1/.git'\'' to '\''.git/modules/sub1'\''
+	EOF
+	git submodule absorbgitdirs 2>actual &&
+	test_cmp expect actual &&
 	git fsck &&
 	test -f sub1/.git &&
 	test -d .git/modules/sub1 &&
@@ -37,7 +43,8 @@ test_expect_success 'absorb the git dir' '
 test_expect_success 'absorbing does not fail for deinitialized submodules' '
 	test_when_finished "git submodule update --init" &&
 	git submodule deinit --all &&
-	git submodule absorbgitdirs &&
+	git submodule absorbgitdirs 2>err &&
+	test_must_be_empty err &&
 	test -d .git/modules/sub1 &&
 	test -d sub1 &&
 	! test -e sub1/.git
@@ -56,7 +63,11 @@ test_expect_success 'setup nested submodule' '
 test_expect_success 'absorb the git dir in a nested submodule' '
 	git status >expect.1 &&
 	git -C sub1/nested rev-parse HEAD >expect.2 &&
-	git submodule absorbgitdirs &&
+	cat >expect <<-\EOF &&
+	Migrating git directory of '\''sub1/nested'\'' from '\''sub1/nested/.git'\'' to '\''.git/modules/sub1/modules/nested'\''
+	EOF
+	git submodule absorbgitdirs 2>actual &&
+	test_cmp expect actual &&
 	test -f sub1/nested/.git &&
 	test -d .git/modules/sub1/modules/nested &&
 	git status >actual.1 &&
@@ -87,7 +98,11 @@ test_expect_success 're-setup nested submodule' '
 test_expect_success 'absorb the git dir in a nested submodule' '
 	git status >expect.1 &&
 	git -C sub1/nested rev-parse HEAD >expect.2 &&
-	git submodule absorbgitdirs &&
+	cat >expect <<-\EOF &&
+	Migrating git directory of '\''sub1'\'' from '\''sub1/.git'\'' to '\''.git/modules/sub1'\''
+	EOF
+	git submodule absorbgitdirs 2>actual &&
+	test_cmp expect actual &&
 	test -f sub1/.git &&
 	test -f sub1/nested/.git &&
 	test -d .git/modules/sub1/modules/nested &&
@@ -107,7 +122,11 @@ test_expect_success 'setup a gitlink with missing .gitmodules entry' '
 test_expect_success 'absorbing the git dir fails for incomplete submodules' '
 	git status >expect.1 &&
 	git -C sub2 rev-parse HEAD >expect.2 &&
-	test_must_fail git submodule absorbgitdirs &&
+	cat >expect <<-\EOF &&
+	fatal: could not lookup name for submodule '\''sub2'\''
+	EOF
+	test_must_fail git submodule absorbgitdirs 2>actual &&
+	test_cmp expect actual &&
 	git -C sub2 fsck &&
 	test -d sub2/.git &&
 	git status >actual &&
@@ -127,8 +146,11 @@ test_expect_success 'setup a submodule with multiple worktrees' '
 '
 
 test_expect_success 'absorbing fails for a submodule with multiple worktrees' '
-	test_must_fail git submodule absorbgitdirs sub3 2>error &&
-	test_i18ngrep "not supported" error
+	cat >expect <<-\EOF &&
+	fatal: could not lookup name for submodule '\''sub2'\''
+	EOF
+	test_must_fail git submodule absorbgitdirs 2>actual &&
+	test_cmp expect actual
 '
 
 test_done
-- 
2.38.0.1467.g709fbdff1a9