[PATCH 4/4] submodule: ignore .gitmodules that is not a regular file

[Junio C Hamano <gitster@pobox.com>]

If .gitmodules exists in the working tree but is a directory, it
would have just tried to use it as if it were a file.  On a platform
that needs FREAD_READS_DIRECTORIES, this would have been hidden by
our own fopen() that pretends as if directory did not exist, so it
is a no-op.  Just to add some documentation value, make sure we
check with file_exists_as_file() instead of file_exists(), the
latter of which will be happy as long as the given path exists no
matter what it is.

Signed-off-by: Junio C Hamano <gitster@pobox.com>
---
 dir.c              | 6 ++++++
 dir.h              | 1 +
 submodule-config.c | 2 +-
 3 files changed, 8 insertions(+), 1 deletion(-)

diff --git a/dir.c b/dir.c
index 73f89f4d8c..d943da93df 100644
--- a/dir.c
+++ b/dir.c
@@ -3142,6 +3142,12 @@ int file_exists(const char *f)
 	return lstat(f, &sb) == 0;
 }
 
+int file_exists_as_file(const char *path)
+{
+	struct stat st;
+	return lstat(path, &st) == 0 && S_ISREG(st.st_mode);
+}
+
 int repo_file_exists(struct repository *repo, const char *path)
 {
 	if (repo != the_repository)
diff --git a/dir.h b/dir.h
index 1398a53fb4..3612dbbf9e 100644
--- a/dir.h
+++ b/dir.h
@@ -475,6 +475,7 @@ void dir_clear(struct dir_struct *dir);
 
 int repo_file_exists(struct repository *repo, const char *path);
 int file_exists(const char *);
+int file_exists_as_file(const char *);
 
 int is_inside_dir(const char *dir);
 int dir_inside_of(const char *subdir, const char *dir);
diff --git a/submodule-config.c b/submodule-config.c
index ec45ea67b9..6c18ae3764 100644
--- a/submodule-config.c
+++ b/submodule-config.c
@@ -801,7 +801,7 @@ static void config_from_gitmodules(config_fn_t fn, struct repository *repo, void
 		char *oidstr = NULL;
 
 		file = repo_worktree_path(repo, GITMODULES_FILE);
-		if (file_exists(file)) {
+		if (file_exists_as_file(file)) {
 			config_source.file = file;
 		} else if (repo_get_oid(repo, GITMODULES_INDEX, &oid) >= 0 ||
 			   repo_get_oid(repo, GITMODULES_HEAD, &oid) >= 0) {
-- 
2.45.2-711-gd2c001ca14