get_sha1_1: allow octopus^12 to be properly parsed.

We probably thought anybody who does more than 9 parents in an
Octopus is insane when this was initially done, but there is no
inherent reason to limit the number of independent topic
branches that happen to mature at the same time.

Our commit-tree allows up to 16 already, so at least we should
prepare to handle what we can produce, if only to be consistent.

Signed-off-by: Junio C Hamano <junkio@cox.net>

sha1_name.c

@@ -388,43 +388,36 @@ static int peel_onion(const char *name, int len, unsigned char *sha1)
 
 static int get_sha1_1(const char *name, int len, unsigned char *sha1)
 {
-	int parent, ret;
+	int ret, has_suffix;
 	const char *cp;
 
-	/* foo^[0-9] or foo^ (== foo^1); we do not do more than 9 parents. */
-	if (len > 2 && name[len-2] == '^' &&
-	    name[len-1] >= '0' && name[len-1] <= '9') {
-		parent = name[len-1] - '0';
-		len -= 2;
-	}
-	else if (len > 1 && name[len-1] == '^') {
-		parent = 1;
-		len--;
-	} else
-		parent = -1;
-
-	if (parent >= 0)
-		return get_parent(name, len, sha1, parent);
-
 	/* "name~3" is "name^^^",
-	 * "name~12" is "name^^^^^^^^^^^^", and
 	 * "name~" and "name~0" are name -- not "name^0"!
+	 * "name^" is not "name^0"; it is "name^1".
 	 */
-	parent = 0;
+	has_suffix = 0;
 	for (cp = name + len - 1; name <= cp; cp--) {
 		int ch = *cp;
 		if ('0' <= ch && ch <= '9')
 			continue;
-		if (ch != '~')
-			parent = -1;
+		if (ch == '~' || ch == '^')
+			has_suffix = ch;
 		break;
 	}
-	if (!parent && *cp == '~') {
+
+	if (has_suffix) {
+		int num = 0;
 		int len1 = cp - name;
 		cp++;
 		while (cp < name + len)
-			parent = parent * 10 + *cp++ - '0';
-		return get_nth_ancestor(name, len1, sha1, parent);
+			num = num * 10 + *cp++ - '0';
+		if (has_suffix == '^') {
+			if (!num && len1 == len - 1)
+				num = 1;
+			return get_parent(name, len1, sha1, num);
+		}
+		/* else if (has_suffix == '~') -- goes without saying */
+		return get_nth_ancestor(name, len1, sha1, num);
 	}
 
 	ret = peel_onion(name, len, sha1);