refs: peeling non-the_repository iterators is BUG

There is currently no support for peeling the current ref of an iterator
iterating over a non-the_repository ref store, and none is needed. Thus,
for now, BUG() if that happens.

Signed-off-by: Jonathan Tan <jonathantanmy@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

refs/files-backend.c

@@ -833,7 +833,7 @@ static struct ref_iterator *files_ref_iterator_begin(
 	 */
 
 	loose_iter = cache_ref_iterator_begin(get_loose_ref_cache(refs),
-					      prefix, 1);
+					      prefix, ref_store->repo, 1);
 
 	/*
 	 * The packed-refs file might contain broken references, for
@@ -1165,7 +1165,8 @@ static int files_pack_refs(struct ref_store *ref_store, unsigned int flags)
 
 	packed_refs_lock(refs->packed_ref_store, LOCK_DIE_ON_ERROR, &err);
 
-	iter = cache_ref_iterator_begin(get_loose_ref_cache(refs), NULL, 0);
+	iter = cache_ref_iterator_begin(get_loose_ref_cache(refs), NULL,
+					the_repository, 0);
 	while ((ok = ref_iterator_advance(iter)) == ITER_OK) {
 		/*
 		 * If the loose reference can be packed, add an entry

refs/packed-backend.c

@@ -886,6 +886,9 @@ static int packed_ref_iterator_peel(struct ref_iterator *ref_iterator,
 	struct packed_ref_iterator *iter =
 		(struct packed_ref_iterator *)ref_iterator;
 
+	if (iter->repo != the_repository)
+		BUG("peeling for non-the_repository is not supported");
+
 	if ((iter->base.flags & REF_KNOWS_PEELED)) {
 		oidcpy(peeled, &iter->peeled);
 		return is_null_oid(&iter->peeled) ? -1 : 0;

refs/ref-cache.c

@@ -435,6 +435,8 @@ struct cache_ref_iterator {
 	 * on from there.)
 	 */
 	struct cache_ref_iterator_level *levels;
+
+	struct repository *repo;
 };
 
 static int cache_ref_iterator_advance(struct ref_iterator *ref_iterator)
@@ -491,6 +493,11 @@ static int cache_ref_iterator_advance(struct ref_iterator *ref_iterator)
 static int cache_ref_iterator_peel(struct ref_iterator *ref_iterator,
 				   struct object_id *peeled)
 {
+	struct cache_ref_iterator *iter =
+		(struct cache_ref_iterator *)ref_iterator;
+
+	if (iter->repo != the_repository)
+		BUG("peeling for non-the_repository is not supported");
 	return peel_object(ref_iterator->oid, peeled) ? -1 : 0;
 }
 
@@ -513,6 +520,7 @@ static struct ref_iterator_vtable cache_ref_iterator_vtable = {
 
 struct ref_iterator *cache_ref_iterator_begin(struct ref_cache *cache,
 					      const char *prefix,
+					      struct repository *repo,
 					      int prime_dir)
 {
 	struct ref_dir *dir;
@@ -547,5 +555,7 @@ struct ref_iterator *cache_ref_iterator_begin(struct ref_cache *cache,
 		level->prefix_state = PREFIX_CONTAINS_DIR;
 	}
 
+	iter->repo = repo;
+
 	return ref_iterator;
 }

refs/ref-cache.h

@@ -238,6 +238,7 @@ struct ref_entry *find_ref_entry(struct ref_dir *dir, const char *refname);
  */
 struct ref_iterator *cache_ref_iterator_begin(struct ref_cache *cache,
 					      const char *prefix,
+					      struct repository *repo,
 					      int prime_dir);
 
 #endif /* REFS_REF_CACHE_H */