parse_object_buffer: correct freeing the buffer

If we exit early in the function parse_object_buffer, we did not
write to *eaten_p. Then the calling function parse_object, which looks
like the following with respect to the eaten variable, cannot rely on a
proper value set in eaten, hence the freeing of the buffer depends
on random values in memory.

	struct object *parse_object(const unsigned char *sha1)
	{
		int eaten;
		...
		obj = parse_object_buffer(sha1, type, size, buffer, &eaten);
		if (!eaten)
			free(buffer);
	}

This change makes sure, the buffer freeing condition is deterministic.

Signed-off-by: Stefan Beller <stefanbeller@googlemail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

Author: stefanbeller

object.c

@@ -135,7 +135,7 @@ struct object *lookup_unknown_object(const unsigned char *sha1)
 struct object *parse_object_buffer(const unsigned char *sha1, enum object_type type, unsigned long size, void *buffer, int *eaten_p)
 {
 	struct object *obj;
-	int eaten = 0;
+	*eaten_p = 0;
 
 	obj = NULL;
 	if (type == OBJ_BLOB) {
@@ -154,7 +154,7 @@ struct object *parse_object_buffer(const unsigned char *sha1, enum object_type t
 			if (!tree->object.parsed) {
 				if (parse_tree_buffer(tree, buffer, size))
 					return NULL;
-				eaten = 1;
+				*eaten_p = 1;
 			}
 		}
 	} else if (type == OBJ_COMMIT) {
@@ -164,7 +164,7 @@ struct object *parse_object_buffer(const unsigned char *sha1, enum object_type t
 				return NULL;
 			if (!commit->buffer) {
 				commit->buffer = buffer;
-				eaten = 1;
+				*eaten_p = 1;
 			}
 			obj = &commit->object;
 		}
@@ -181,7 +181,6 @@ struct object *parse_object_buffer(const unsigned char *sha1, enum object_type t
 	}
 	if (obj && obj->type == OBJ_NONE)
 		obj->type = type;
-	*eaten_p = eaten;
 	return obj;
 }