[PATCH v2 8/8] fsck: complain when .gitattributes or .gitignore is a symlink

[Jeff King <peff@peff.net>]

The previous commit made it impossible to have a symlinked
.gitattributes or .gitignore file via verify_path(). Let's add the same
check to fsck, which matches how we handle .gitmodules symlinks, via
b7b1fca175 (fsck: complain when .gitmodules is a symlink, 2018-05-04).

Note that we won't add these to the existing gitmodules block. The logic
for gitmodules is a bit more complicated, as we also check the content
of non-symlink instances we find. But for these new files, there is no
content check; we're just looking at the name and mode of the tree entry
(and we can avoid even the complicated name checks in the common case
that the mode doesn't indicate a symlink).

We can reuse the test helper function we defined for .gitmodules,
though (and this covers the verify_path() change from the previous
commit, as well).

Signed-off-by: Jeff King <peff@peff.net>
---
 fsck.c                       | 15 +++++++++++++++
 t/t7450-bad-dotgitx-files.sh |  8 ++++++++
 2 files changed, 23 insertions(+)

diff --git a/fsck.c b/fsck.c
index 024810139b..fcd3f268b1 100644
--- a/fsck.c
+++ b/fsck.c
@@ -67,6 +67,8 @@ static struct oidset gitmodules_done = OIDSET_INIT;
 	FUNC(GITMODULES_URL, ERROR) \
 	FUNC(GITMODULES_PATH, ERROR) \
 	FUNC(GITMODULES_UPDATE, ERROR) \
+	FUNC(GITIGNORE_SYMLINK, ERROR) \
+	FUNC(GITATTRIBUTES_SYMLINK, ERROR) \
 	/* warnings */ \
 	FUNC(BAD_FILEMODE, WARN) \
 	FUNC(EMPTY_NAME, WARN) \
@@ -688,6 +690,19 @@ static int fsck_tree(const struct object_id *tree_oid,
 						 ".gitmodules is a symbolic link");
 		}
 
+		if (S_ISLNK(mode)) {
+			if (is_hfs_dotgitignore(name) ||
+			    is_ntfs_dotgitignore(name))
+				retval += report(options, tree_oid, OBJ_TREE,
+						 FSCK_MSG_GITIGNORE_SYMLINK,
+						 ".gitignore is a symlink");
+			if (is_hfs_dotgitattributes(name) ||
+			    is_ntfs_dotgitattributes(name))
+				retval += report(options, tree_oid, OBJ_TREE,
+						 FSCK_MSG_GITATTRIBUTES_SYMLINK,
+						 ".gitattributes is a symlink");
+		}
+
 		if ((backslash = strchr(name, '\\'))) {
 			while (backslash) {
 				backslash++;
diff --git a/t/t7450-bad-dotgitx-files.sh b/t/t7450-bad-dotgitx-files.sh
index 0cd0f71c39..326b34e167 100755
--- a/t/t7450-bad-dotgitx-files.sh
+++ b/t/t7450-bad-dotgitx-files.sh
@@ -193,6 +193,14 @@ check_forbidden_symlink gitmodules vanilla .gitmodules
 check_forbidden_symlink gitmodules ntfs ".gitmodules ."
 check_forbidden_symlink gitmodules hfs ".${u200c}gitmodules"
 
+check_forbidden_symlink gitattributes vanilla .gitattributes
+check_forbidden_symlink gitattributes ntfs ".gitattributes ."
+check_forbidden_symlink gitattributes hfs ".${u200c}gitattributes"
+
+check_forbidden_symlink gitignore vanilla .gitignore
+check_forbidden_symlink gitignore ntfs ".gitignore ."
+check_forbidden_symlink gitignore hfs ".${u200c}gitignore"
+
 test_expect_success 'fsck detects non-blob .gitmodules' '
 	git init non-blob &&
 	(
-- 
2.28.0.1295.gf70bcb366f