path: implement common_dir handling in git_pathdup_submodule()

When submodule is a linked worktree, "git diff --submodule" and other
calls which directly access the submodule's object database do not correctly
calculate its path. Fix it by changing the git_pathdup_submodule() behavior,
to use either common or per-worktree directory.

Do it similarly as for parent repository, but ignore the GIT_COMMON_DIR
environment variable, because it would mean common directory for the parent
repository and does not make sense for submodule.

Also add test for functionality which uses this call.

Signed-off-by: Max Kirillov <max@max630.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

1 files changed, 18 insertions, 4 deletions

diff --git a/path.c b/path.c
index 95acbaf..22b9e0b 100644
--- a/path.c
+++ b/path.c
@@ -98,7 +98,7 @@ static const char *common_list[] = {
 	NULL
 };
 
-static void update_common_dir(struct strbuf *buf, int git_dir_len)
+static void update_common_dir(struct strbuf *buf, int git_dir_len, const char *common_dir)
 {
 	char *base = buf->buf + git_dir_len;
 	const char **p;
@@ -115,12 +115,16 @@ static void update_common_dir(struct strbuf *buf, int git_dir_len)
 			path++;
 			is_dir = 1;
 		}
+
+		if (!common_dir)
+			common_dir = get_git_common_dir();
+
 		if (is_dir && dir_prefix(base, path)) {
-			replace_dir(buf, git_dir_len, get_git_common_dir());
+			replace_dir(buf, git_dir_len, common_dir);
 			return;
 		}
 		if (!is_dir && !strcmp(base, path)) {
-			replace_dir(buf, git_dir_len, get_git_common_dir());
+			replace_dir(buf, git_dir_len, common_dir);
 			return;
 		}
 	}
@@ -160,7 +164,7 @@ static void adjust_git_path(struct strbuf *buf, int git_dir_len)
 	else if (git_db_env && dir_prefix(base, "objects"))
 		replace_dir(buf, git_dir_len + 7, get_object_directory());
 	else if (git_common_dir_env)
-		update_common_dir(buf, git_dir_len);
+		update_common_dir(buf, git_dir_len, NULL);
 }
 
 static void do_git_path(struct strbuf *buf, const char *fmt, va_list args)
@@ -228,6 +232,8 @@ static void do_submodule_path(struct strbuf *buf, const char *path,
 			      const char *fmt, va_list args)
 {
 	const char *git_dir;
+	struct strbuf git_submodule_common_dir = STRBUF_INIT;
+	struct strbuf git_submodule_dir = STRBUF_INIT;
 
 	strbuf_addstr(buf, path);
 	if (buf->len && buf->buf[buf->len - 1] != '/')
@@ -240,9 +246,17 @@ static void do_submodule_path(struct strbuf *buf, const char *path,
 		strbuf_addstr(buf, git_dir);
 	}
 	strbuf_addch(buf, '/');
+	strbuf_addstr(&git_submodule_dir, buf->buf);
 
 	strbuf_vaddf(buf, fmt, args);
+
+	if (get_common_dir_noenv(&git_submodule_common_dir, git_submodule_dir.buf))
+		update_common_dir(buf, git_submodule_dir.len, git_submodule_common_dir.buf);
+
 	strbuf_cleanup_path(buf);
+
+	strbuf_release(&git_submodule_dir);
+	strbuf_release(&git_submodule_common_dir);
 }
 
 char *git_pathdup_submodule(const char *path, const char *fmt, ...)