diff --git a/cache.h b/cache.h
index 871a167..9a600a8 100644
--- a/cache.h
+++ b/cache.h
@@ -1386,6 +1386,7 @@
 int repo_get_oid_tree(struct repository *r, const char *str, struct object_id *oid);
 int repo_get_oid_treeish(struct repository *r, const char *str, struct object_id *oid);
 int repo_get_oid_blob(struct repository *r, const char *str, struct object_id *oid);
+int repo_get_oid_mb(struct repository *r, const char *str, struct object_id *oid);
 void maybe_die_on_misspelt_object_name(struct repository *repo,
 				       const char *name,
 				       const char *prefix);
@@ -1399,6 +1400,7 @@
 #define get_oid_tree(str, oid)		repo_get_oid_tree(the_repository, str, oid)
 #define get_oid_treeish(str, oid)	repo_get_oid_treeish(the_repository, str, oid)
 #define get_oid_blob(str, oid)		repo_get_oid_blob(the_repository, str, oid)
+#define get_oid_mb(str, oid) 		repo_get_oid_mb(the_repository, str, oid)
 
 typedef int each_abbrev_fn(const struct object_id *oid, void *);
 int repo_for_each_abbrev(struct repository *r, const char *prefix, each_abbrev_fn, void *);
@@ -1486,7 +1488,6 @@
 			       unsigned allowed);
 #define interpret_branch_name(str, len, buf, allowed) \
 	repo_interpret_branch_name(the_repository, str, len, buf, allowed)
-extern int get_oid_mb(const char *str, struct object_id *oid);
 
 extern int validate_headref(const char *ref);
 
diff --git a/sha1-name.c b/sha1-name.c
index d494963..cf314eb 100644
--- a/sha1-name.c
+++ b/sha1-name.c
@@ -1338,7 +1338,9 @@
 	return retval;
 }
 
-int get_oid_mb(const char *name, struct object_id *oid)
+int repo_get_oid_mb(struct repository *r,
+		    const char *name,
+		    struct object_id *oid)
 {
 	struct commit *one, *two;
 	struct commit_list *mbs;
@@ -1348,27 +1350,29 @@
 
 	dots = strstr(name, "...");
 	if (!dots)
-		return get_oid(name, oid);
+		return repo_get_oid(r, name, oid);
 	if (dots == name)
-		st = get_oid("HEAD", &oid_tmp);
+		st = repo_get_oid(r, "HEAD", &oid_tmp);
 	else {
 		struct strbuf sb;
 		strbuf_init(&sb, dots - name);
 		strbuf_add(&sb, name, dots - name);
-		st = get_oid_committish(sb.buf, &oid_tmp);
+		st = repo_get_oid_committish(r, sb.buf, &oid_tmp);
 		strbuf_release(&sb);
 	}
 	if (st)
 		return st;
-	one = lookup_commit_reference_gently(the_repository, &oid_tmp, 0);
+	one = lookup_commit_reference_gently(r, &oid_tmp, 0);
 	if (!one)
 		return -1;
 
-	if (get_oid_committish(dots[3] ? (dots + 3) : "HEAD", &oid_tmp))
+	if (repo_get_oid_committish(r, dots[3] ? (dots + 3) : "HEAD", &oid_tmp))
 		return -1;
-	two = lookup_commit_reference_gently(the_repository, &oid_tmp, 0);
+	two = lookup_commit_reference_gently(r, &oid_tmp, 0);
 	if (!two)
 		return -1;
+	if (r != the_repository)
+		BUG("sorry get_merge_bases() can't take struct repository yet");
 	mbs = get_merge_bases(one, two);
 	if (!mbs || mbs->next)
 		st = -1;