diff --git a/cache.h b/cache.h
index b829410f6d..f837732f79 100644
--- a/cache.h
+++ b/cache.h
@@ -1124,6 +1124,8 @@ extern int get_sha1_blob(const char *str, unsigned char *sha1);
 extern void maybe_die_on_misspelt_object_name(const char *name, const char *prefix);
 extern int get_sha1_with_context(const char *str, unsigned flags, unsigned char *sha1, struct object_context *orc);
 
+extern int get_oid(const char *str, struct object_id *oid);
+
 typedef int each_abbrev_fn(const unsigned char *sha1, void *);
 extern int for_each_abbrev(const char *prefix, each_abbrev_fn, void *);
 
diff --git a/sha1_name.c b/sha1_name.c
index 3acf221f92..1ae20fec15 100644
--- a/sha1_name.c
+++ b/sha1_name.c
@@ -1214,6 +1214,15 @@ int get_sha1(const char *name, unsigned char *sha1)
 	return get_sha1_with_context(name, 0, sha1, &unused);
 }
 
+/*
+ * This is like "get_sha1()", but for struct object_id.
+ */
+int get_oid(const char *name, struct object_id *oid)
+{
+	return get_sha1(name, oid->hash);
+}
+
+
 /*
  * Many callers know that the user meant to name a commit-ish by
  * syntactical positions where the object name appears.  Calling this