Update callers of check_ref_format()

This updates send-pack and fast-import to use symbolic constants
for checking the return values from check_ref_format(), and also
futureproof the logic in lock_any_ref_for_update() to explicitly
name the case that is usually considered an error but is Ok for
this particular use.

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

builtin-send-pack.c

@@ -541,10 +541,12 @@ static void verify_remote_names(int nr_heads, const char **heads)
 		remote = remote ? (remote + 1) : heads[i];
 		switch (check_ref_format(remote)) {
 		case 0: /* ok */
-		case -2: /* ok but a single level -- that is fine for
+		case CHECK_REF_FORMAT_ONELEVEL:
+			/* ok but a single level -- that is fine for
 			 * a match pattern.
 			 */
-		case -3: /* ok but ends with a pattern-match character */
+		case CHECK_REF_FORMAT_WILDCARD:
+			/* ok but ends with a pattern-match character */
 			continue;
 		}
 		die("remote part of refspec is not a valid name in %s",

fast-import.c

@@ -643,7 +643,8 @@ static struct branch *new_branch(const char *name)
 		die("Invalid attempt to create duplicate branch: %s", name);
 	switch (check_ref_format(name)) {
 	case 0: break; /* its valid */
-	case -2: break; /* valid, but too few '/', allow anyway */
+	case CHECK_REF_FORMAT_ONELEVEL:
+		break; /* valid, but too few '/', allow anyway */
 	default:
 		die("Branch name doesn't conform to GIT standards: %s", name);
 	}

refs.c

@@ -822,10 +822,10 @@ struct ref_lock *lock_ref_sha1(const char *ref, const unsigned char *old_sha1)
 struct ref_lock *lock_any_ref_for_update(const char *ref, const unsigned char *old_sha1, int flags)
 {
 	switch (check_ref_format(ref)) {
-	case CHECK_REF_FORMAT_ERROR:
-	case CHECK_REF_FORMAT_WILDCARD:
-		return NULL;
 	default:
+		return NULL;
+	case 0:
+	case CHECK_REF_FORMAT_ONELEVEL:
 		return lock_ref_sha1_basic(ref, old_sha1, flags, NULL);
 	}
 }