attr.c: correct ugly hack for git_all_attrs()

The collect_some_attrs() function has an ugly hack since

06a604e6 (attr: avoid heavy work when we know the specified attr is
not defined, 2014-12-28) added an optimization that relies on the
fact that the caller knows what attributes it is interested in, so
that we can leave once we know the final answer for all the
attributes the caller asked.

git_all_attrs() that asks "what attributes are on this path?"
however does not know what attributes it is interested in, other
than the vague "we are interested in all of them", which is not a
very useful thing to say.  As a way to disable this optimization
for this caller, the said commit added a code to skip it when
the caller passes a NULL for the check structure.

However, it skipped the optimization not when check is NULL, but
when the number of attributes being checked is 0, which is
unnecessarily pessimistic.

Signed-off-by: Junio C Hamano <gitster@pobox.com>

1 files changed, 8 insertions, 16 deletions

diff --git a/attr.c b/attr.c
index abf23d8f7c..8d8df20669 100644
--- a/attr.c
+++ b/attr.c
@@ -748,8 +748,8 @@ static int attr_check_is_dynamic(const struct git_attr_check *check)
 
 /*
  * Collect attributes for path into the array pointed to by
- * check_all_attr. If num is non-zero, only attributes in check[] are
- * collected. Otherwise all attributes are collected.
+ * check_all_attr.  If check is not NULL, only attributes in
+ * check[] are collected. Otherwise all attributes are collected.
  */
 static void collect_some_attrs(const char *path, int pathlen,
 			       struct git_attr_check *check)
@@ -759,17 +759,6 @@ static void collect_some_attrs(const char *path, int pathlen,
 	int i, rem, dirlen;
 	const char *cp, *last_slash = NULL;
 	int basename_offset;
-	int num;
-	struct git_attr_check_elem *celem;
-
-	if (!check) {
-		/* Yuck - ugly git_all_attrs() hack! */
-		celem = NULL;
-		num = 0;
-	} else {
-		celem = check->check;
-		num = check->check_nr;
-	}
 
 	for (cp = path; cp < path + pathlen; cp++) {
 		if (*cp == '/' && cp[1])
@@ -786,9 +775,12 @@ static void collect_some_attrs(const char *path, int pathlen,
 	prepare_attr_stack(path, dirlen);
 	for (i = 0; i < attr_nr; i++)
 		check_all_attr[i].value = ATTR__UNKNOWN;
-	if (num && !cannot_trust_maybe_real) {
+
+	if (check && !cannot_trust_maybe_real) {
+		struct git_attr_check_elem *celem = check->check;
+
 		rem = 0;
-		for (i = 0; i < num; i++) {
+		for (i = 0; i < check->check_nr; i++) {
 			if (!celem[i].attr->maybe_real) {
 				struct git_attr_check_elem *c;
 				c = check_all_attr + celem[i].attr->attr_nr;
@@ -796,7 +788,7 @@ static void collect_some_attrs(const char *path, int pathlen,
 				rem++;
 			}
 		}
-		if (rem == num)
+		if (rem == check->check_nr)
 			return;
 	}