usage(commit_tree_usage);
                        if (get_oid_commit(argv[i], &oid))
                                die("Not a valid object name %s", argv[i]);
-                       assert_sha1_type(oid.hash, OBJ_COMMIT);
+                       assert_oid_type(&oid, OBJ_COMMIT);
                        new_parent(lookup_commit(&oid), &parents);
                        continue;
                }
                        if (fd && close(fd))
                                die_errno("git commit-tree: failed to close '%s'",
                                          argv[i]);
-                       strbuf_complete_line(&buffer);
                        continue;
                }
 
                        die_errno("git commit-tree: failed to read");
        }
 
-       if (commit_tree(buffer.buf, buffer.len, tree_oid.hash, parents,
-                       commit_oid.hash, NULL, sign_commit)) {
+       if (commit_tree(buffer.buf, buffer.len, &tree_oid, parents, &commit_oid,
+                       NULL, sign_commit)) {
                strbuf_release(&buffer);
                return 1;
        }