pathspec: pass directory indicator to match_pathspec_item()

This patch activates the DO_MATCH_DIRECTORY code in m_p_i(), which
makes "git diff HEAD submodule/" and "git diff HEAD submodule" produce
the same output. Previously only the version without trailing slash
returns the difference (if any).

That's the effect of new ce_path_match(). dir_path_match() is not
executed by the new tests. And it should not introduce regressions.

Previously if path "dir/" is passed in with pathspec "dir/", they
obviously match. With new dir_path_match(), the path becomes
_directory_ "dir" vs pathspec "dir/", which is not executed by the old
code path in m_p_i(). The new code path is executed and produces the
same result.

The other case is pathspec "dir" and path "dir/" is now turned to
"dir" (with DO_MATCH_DIRECTORY). Still the same result before or after
the patch.

So why change? Because of the next patch about clean.c.

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

builtin/clean.c

@@ -962,7 +962,7 @@ int cmd_clean(int argc, const char **argv, const char *prefix)
 
 		if (pathspec.nr)
 			matches = match_pathspec(&pathspec, ent->name,
-						 len, 0, NULL);
+						 len, 0, NULL, 0);
 
 		if (S_ISDIR(st.st_mode)) {
 			if (remove_directories || (matches == MATCHED_EXACTLY)) {

builtin/ls-files.c

@@ -140,7 +140,8 @@ static void show_ce_entry(const char *tag, const struct cache_entry *ce)
 		die("git ls-files: internal error - cache entry not superset of prefix");
 
 	if (!match_pathspec(&pathspec, ce->name, ce_namelen(ce),
-			    len, ps_matched))
+			    len, ps_matched,
+			    S_ISDIR(ce->ce_mode) || S_ISGITLINK(ce->ce_mode)))
 		return;
 
 	if (tag && *tag && show_valid_bit &&
@@ -197,7 +198,7 @@ static void show_ru_info(void)
 		if (len < max_prefix_len)
 			continue; /* outside of the prefix */
 		if (!match_pathspec(&pathspec, path, len,
-				    max_prefix_len, ps_matched))
+				    max_prefix_len, ps_matched, 0))
 			continue; /* uninterested */
 		for (i = 0; i < 3; i++) {
 			if (!ui->mode[i])

dir.c

@@ -360,10 +360,10 @@ static int do_match_pathspec(const struct pathspec *ps,
 
 int match_pathspec(const struct pathspec *ps,
 		   const char *name, int namelen,
-		   int prefix, char *seen)
+		   int prefix, char *seen, int is_dir)
 {
 	int positive, negative;
-	unsigned flags = 0;
+	unsigned flags = is_dir ? DO_MATCH_DIRECTORY : 0;
 	positive = do_match_pathspec(ps, name, namelen,
 				     prefix, seen, flags);
 	if (!(ps->magic & PATHSPEC_EXCLUDE) || !positive)

dir.h

@@ -134,7 +134,7 @@ extern int no_wildcard(const char *string);
 extern char *common_prefix(const struct pathspec *pathspec);
 extern int match_pathspec(const struct pathspec *pathspec,
 			  const char *name, int namelen,
-			  int prefix, char *seen);
+			  int prefix, char *seen, int is_dir);
 extern int within_depth(const char *name, int namelen, int depth, int max_depth);
 
 extern int fill_directory(struct dir_struct *dir, const struct pathspec *pathspec);
@@ -209,14 +209,18 @@ static inline int ce_path_match(const struct cache_entry *ce,
 				const struct pathspec *pathspec,
 				char *seen)
 {
-	return match_pathspec(pathspec, ce->name, ce_namelen(ce), 0, seen);
+	return match_pathspec(pathspec, ce->name, ce_namelen(ce), 0, seen,
+			      S_ISDIR(ce->ce_mode) || S_ISGITLINK(ce->ce_mode));
 }
 
 static inline int dir_path_match(const struct dir_entry *ent,
 				 const struct pathspec *pathspec,
 				 int prefix, char *seen)
 {
-	return match_pathspec(pathspec, ent->name, ent->len, prefix, seen);
+	int has_trailing_dir = ent->len && ent->name[ent->len - 1] == '/';
+	int len = has_trailing_dir ? ent->len - 1 : ent->len;
+	return match_pathspec(pathspec, ent->name, len, prefix, seen,
+			      has_trailing_dir);
 }
 
 #endif

rerere.c

@@ -673,7 +673,7 @@ int rerere_forget(struct pathspec *pathspec)
 	for (i = 0; i < conflict.nr; i++) {
 		struct string_list_item *it = &conflict.items[i];
 		if (!match_pathspec(pathspec, it->string,
-				    strlen(it->string), 0, NULL))
+				    strlen(it->string), 0, NULL, 0))
 			continue;
 		rerere_forget_one_path(it->string, &merge_rr);
 	}

t/t4010-diff-pathspec.sh

@@ -127,4 +127,10 @@ test_expect_success 'diff-tree ignores trailing slash on submodule path' '
 	test_cmp expect actual
 '
 
+test_expect_success 'diff-cache ignores trailing slash on submodule path' '
+	git diff --name-only HEAD^ submod >expect &&
+	git diff --name-only HEAD^ submod/ >actual &&
+	test_cmp expect actual
+'
+
 test_done