MERGE_RECURSIVE_THEIRS
        } recursive_variant;
        const char *subtree_shift;
-       unsigned buffer_output : 1;
+       unsigned buffer_output; /* 1: output at end, 2: keep buffered */
        unsigned renormalize : 1;
        long xdl_opts;
        int verbosity;
  * virtual commits and call merge_recursive() proper.
  */
 int merge_recursive_generic(struct merge_options *o,
-                           const unsigned char *head,
-                           const unsigned char *merge,
+                           const struct object_id *head,
+                           const struct object_id *merge,
                            int num_ca,
-                           const unsigned char **ca,
+                           const struct object_id **ca,
                            struct commit **result);
 
 void init_merge_options(struct merge_options *o);