merge with /dev/null as base, instead of punting O==empty case

diff --git a/tag.c b/tag.c
index 4041af2572a4427a03bc8955137b7d2211f9d770..e574c4b7a496d3a1d113801214197a04d5c74d42 100644 (file)
--- a/tag.c
+++ b/tag.c
@@ -3,6 +3,18 @@
 
 const char *tag_type = "tag";
 
+struct object *deref_tag(struct object *o, const char *warn, int warnlen)
+{
+       while (o && o->type == tag_type)
+               o = parse_object(((struct tag *)o)->tagged->sha1);
+       if (!o && warn) {
+               if (!warnlen)
+                       warnlen = strlen(warn);
+               error("missing object referenced by '%.*s'", warnlen, warn);
+       }
+       return o;
+}
+
 struct tag *lookup_tag(const unsigned char *sha1)
 {
         struct object *obj = lookup_object(sha1);
@@ -28,6 +40,7 @@ int parse_tag_buffer(struct tag *item, void *data, unsigned long size)
        int typelen, taglen;
        unsigned char object[20];
        const char *type_line, *tag_line, *sig_line;
+       char type[20];
 
         if (item->object.parsed)
                 return 0;
@@ -38,10 +51,6 @@ int parse_tag_buffer(struct tag *item, void *data, unsigned long size)
        if (memcmp("object ", data, 7) || get_sha1_hex(data + 7, object))
                return -1;
 
-       item->tagged = parse_object(object);
-       if (item->tagged)
-               add_ref(&item->object, item->tagged);
-
        type_line = data + 48;
        if (memcmp("\ntype ", type_line-1, 6))
                return -1;
@@ -58,11 +67,17 @@ int parse_tag_buffer(struct tag *item, void *data, unsigned long size)
        typelen = tag_line - type_line - strlen("type \n");
        if (typelen >= 20)
                return -1;
+       memcpy(type, type_line + 5, typelen);
+       type[typelen] = '\0';
        taglen = sig_line - tag_line - strlen("tag \n");
        item->tag = xmalloc(taglen + 1);
        memcpy(item->tag, tag_line + 4, taglen);
        item->tag[taglen] = '\0';
 
+       item->tagged = lookup_object_type(object, type);
+       if (item->tagged)
+               add_ref(&item->object, item->tagged);
+
        return 0;
 }