* @self: Repo
* @refspec: A refspec
* @allow_noent: Do not throw an error if refspec does not exist
- * @out_rev: (out) (transfer full): A checksum,or %NULL if @allow_noent is true and it does not exist
+ * @out_rev: (out) (nullable) (transfer full): A checksum,or %NULL if @allow_noent is true and it does not exist
* @error: Error
*
* Look up the given refspec, returning the checksum it references in
* @refspec: A refspec
* @allow_noent: Do not throw an error if refspec does not exist
* @flags: Options controlling behavior
- * @out_rev: (out) (transfer full): A checksum,or %NULL if @allow_noent is true and it does not exist
+ * @out_rev: (out) (nullable) (transfer full): A checksum,or %NULL if @allow_noent is true and it does not exist
* @error: Error
*
* Look up the given refspec, returning the checksum it references in