Merge branch 'js/builtin-rebase-perf-fix'

Code clean-up with correction to make the reimplemented "git
rebase" a more faithful rewrite of the original, which also regains
performance.

* js/builtin-rebase-perf-fix:
built-in rebase: reinstate `checkout -q` behavior where appropriate
rebase: prepare reset_head() for more flags
rebase: consolidate clean-up code before leaving reset_head()

diff --combined builtin/rebase.c
index 6db1b7cc56fb274f56ba311f79296e9f2a373cd7,dc78c1497dee8eb9a278606cf109c424d128c3d7..337c5c7f99f748b802ed2d77bb8ed48672174fe9
--- 1/builtin/rebase.c
--- 2/builtin/rebase.c
+++ b/builtin/rebase.c
@@@ -522,12 -522,17 +522,17 @@@ finished_rebase
  
  #define GIT_REFLOG_ACTION_ENVIRONMENT "GIT_REFLOG_ACTION"
  
+ #define RESET_HEAD_DETACH (1<<0)
+ #define RESET_HEAD_HARD (1<<1)
+ 
  static int reset_head(struct object_id *oid, const char *action,
-                     const char *switch_to_branch, int detach_head,
+                     const char *switch_to_branch, unsigned flags,
                      const char *reflog_orig_head, const char *reflog_head)
  {
+       unsigned detach_head = flags & RESET_HEAD_DETACH;
+       unsigned reset_hard = flags & RESET_HEAD_HARD;
        struct object_id head_oid;
-       struct tree_desc desc;
+       struct tree_desc desc[2] = { { NULL }, { NULL } };
        struct lock_file lock = LOCK_INIT;
        struct unpack_trees_options unpack_tree_opts;
        struct tree *tree;
@@@ -536,60 -541,62 +541,62 @@@
        size_t prefix_len;
        struct object_id *orig = NULL, oid_orig,
                *old_orig = NULL, oid_old_orig;
-       int ret = 0;
+       int ret = 0, nr = 0;
  
        if (switch_to_branch && !starts_with(switch_to_branch, "refs/"))
                BUG("Not a fully qualified branch: '%s'", switch_to_branch);
  
-       if (hold_locked_index(&lock, LOCK_REPORT_ON_ERROR) < 0)
-               return -1;
+       if (hold_locked_index(&lock, LOCK_REPORT_ON_ERROR) < 0) {
+               ret = -1;
+               goto leave_reset_head;
+       }
  
-       if (!oid) {
-               if (get_oid("HEAD", &head_oid)) {
-                       rollback_lock_file(&lock);
-                       return error(_("could not determine HEAD revision"));
-               }
-               oid = &head_oid;
+       if ((!oid || !reset_hard) && get_oid("HEAD", &head_oid)) {
+               ret = error(_("could not determine HEAD revision"));
+               goto leave_reset_head;
        }
  
+       if (!oid)
+               oid = &head_oid;
+ 
        memset(&unpack_tree_opts, 0, sizeof(unpack_tree_opts));
        setup_unpack_trees_porcelain(&unpack_tree_opts, action);
        unpack_tree_opts.head_idx = 1;
        unpack_tree_opts.src_index = the_repository->index;
        unpack_tree_opts.dst_index = the_repository->index;
-       unpack_tree_opts.fn = oneway_merge;
+       unpack_tree_opts.fn = reset_hard ? oneway_merge : twoway_merge;
        unpack_tree_opts.update = 1;
        unpack_tree_opts.merge = 1;
        if (!detach_head)
                unpack_tree_opts.reset = 1;
  
        if (read_index_unmerged(the_repository->index) < 0) {
-               rollback_lock_file(&lock);
-               return error(_("could not read index"));
+               ret = error(_("could not read index"));
+               goto leave_reset_head;
        }
  
-       if (!fill_tree_descriptor(&desc, oid)) {
-               error(_("failed to find tree of %s"), oid_to_hex(oid));
-               rollback_lock_file(&lock);
-               free((void *)desc.buffer);
-               return -1;
+       if (!reset_hard && !fill_tree_descriptor(&desc[nr++], &head_oid)) {
+               ret = error(_("failed to find tree of %s"), oid_to_hex(oid));
+               goto leave_reset_head;
        }
  
-       if (unpack_trees(1, &desc, &unpack_tree_opts)) {
-               rollback_lock_file(&lock);
-               free((void *)desc.buffer);
-               return -1;
+       if (!fill_tree_descriptor(&desc[nr++], oid)) {
+               ret = error(_("failed to find tree of %s"), oid_to_hex(oid));
+               goto leave_reset_head;
+       }
+ 
+       if (unpack_trees(nr, desc, &unpack_tree_opts)) {
+               ret = -1;
+               goto leave_reset_head;
        }
  
        tree = parse_tree_indirect(oid);
        prime_cache_tree(the_repository->index, tree);
  
-       if (write_locked_index(the_repository->index, &lock, COMMIT_LOCK) < 0)
+       if (write_locked_index(the_repository->index, &lock, COMMIT_LOCK) < 0) {
                ret = error(_("could not write index"));
-       free((void *)desc.buffer);
- 
-       if (ret)
-               return ret;
+               goto leave_reset_head;
+       }
  
        reflog_action = getenv(GIT_REFLOG_ACTION_ENVIRONMENT);
        strbuf_addf(&msg, "%s: ", reflog_action ? reflog_action : "rebase");
@@@ -613,8 -620,7 +620,8 @@@
                reflog_head = msg.buf;
        }
        if (!switch_to_branch)
 -              ret = update_ref(reflog_head, "HEAD", oid, orig, REF_NO_DEREF,
 +              ret = update_ref(reflog_head, "HEAD", oid, orig,
 +                               detach_head ? REF_NO_DEREF : 0,
                                 UPDATE_REFS_MSG_ON_ERR);
        else {
                ret = create_symref("HEAD", switch_to_branch, msg.buf);
@@@ -623,7 -629,11 +630,11 @@@
                                         UPDATE_REFS_MSG_ON_ERR);
        }
  
+ leave_reset_head:
        strbuf_release(&msg);
+       rollback_lock_file(&lock);
+       while (nr)
+               free((void *)desc[--nr].buffer);
        return ret;
  }
  
@@@ -704,9 -714,6 +715,9 @@@ static int parse_opt_merge(const struc
  {
        struct rebase_options *opts = opt->value;
  
 +      BUG_ON_OPT_NEG(unset);
 +      BUG_ON_OPT_ARG(arg);
 +
        if (!is_interactive(opts))
                opts->type = REBASE_MERGE;
  
@@@ -719,9 -726,6 +730,9 @@@ static int parse_opt_interactive(const 
  {
        struct rebase_options *opts = opt->value;
  
 +      BUG_ON_OPT_NEG(unset);
 +      BUG_ON_OPT_ARG(arg);
 +
        opts->type = REBASE_INTERACTIVE;
        opts->flags |= REBASE_INTERACTIVE_EXPLICIT;
  
@@@ -1007,7 -1011,8 +1018,8 @@@ int cmd_rebase(int argc, const char **a
                rerere_clear(&merge_rr);
                string_list_clear(&merge_rr, 1);
  
-               if (reset_head(NULL, "reset", NULL, 0, NULL, NULL) < 0)
+               if (reset_head(NULL, "reset", NULL, RESET_HEAD_HARD,
+                              NULL, NULL) < 0)
                        die(_("could not discard worktree changes"));
                if (read_basic_state(&options))
                        exit(1);
@@@ -1023,7 -1028,8 +1035,8 @@@
                if (read_basic_state(&options))
                        exit(1);
                if (reset_head(&options.orig_head, "reset",
-                              options.head_name, 0, NULL, NULL) < 0)
+                              options.head_name, RESET_HEAD_HARD,
+                              NULL, NULL) < 0)
                        die(_("could not move back to %s"),
                            oid_to_hex(&options.orig_head));
                ret = finish_rebase(&options);
@@@ -1387,7 -1393,7 +1400,7 @@@
                        write_file(autostash, "%s", oid_to_hex(&oid));
                        printf(_("Created autostash: %s\n"), buf.buf);
                        if (reset_head(&head->object.oid, "reset --hard",
-                                      NULL, 0, NULL, NULL) < 0)
+                                      NULL, RESET_HEAD_HARD, NULL, NULL) < 0)
                                die(_("could not reset --hard"));
                        printf(_("HEAD is now at %s"),
                               find_unique_abbrev(&head->object.oid,
@@@ -1507,8 -1513,8 +1520,8 @@@
                         "it...\n"));
  
        strbuf_addf(&msg, "rebase: checkout %s", options.onto_name);
-       if (reset_head(&options.onto->object.oid, "checkout", NULL, 1,
-           NULL, msg.buf))
+       if (reset_head(&options.onto->object.oid, "checkout", NULL,
+                      RESET_HEAD_DETACH, NULL, msg.buf))
                die(_("Could not detach HEAD"));
        strbuf_release(&msg);