Merge branch 'js/sequencer-and-root-commits'
authorJunio C Hamano <gitster@pobox.com>
Wed, 30 May 2018 05:04:04 +0000 (14:04 +0900)
committerJunio C Hamano <gitster@pobox.com>
Wed, 30 May 2018 05:04:04 +0000 (14:04 +0900)
The implementation of "git rebase -i --root" has been updated to use
the sequencer machinery more.

* js/sequencer-and-root-commits:
rebase --rebase-merges: root commits can be cousins, too
rebase --rebase-merges: a "merge" into a new root is a fast-forward
sequencer: allow introducing new root commits
rebase -i --root: let the sequencer handle even the initial part
sequencer: learn about the special "fake root commit" handling
sequencer: extract helper to update active_cache_tree

1  2 
sequencer.c
sequencer.h
diff --combined sequencer.c
index 1ce63261a32a2398c3916fd41f577db58478fe0f,01e561bc20ec39587c6b4852c3deff9beb20a3f4..abb6c5dc26c04e21607615326c4d101cd85d5c00
@@@ -78,6 -78,13 +78,6 @@@ static GIT_PATH_FUNC(rebase_path_messag
   * previous commit and from the first squash/fixup commit are written
   * to it. The commit message for each subsequent squash/fixup commit
   * is appended to the file as it is processed.
 - *
 - * The first line of the file is of the form
 - *     # This is a combination of $count commits.
 - * where $count is the number of commits whose messages have been
 - * written to the file so far (including the initial "pick" commit).
 - * Each time that a commit message is processed, this line is read and
 - * updated. It is deleted just before the combined commit is made.
   */
  static GIT_PATH_FUNC(rebase_path_squash_msg, "rebase-merge/message-squash")
  /*
   * commit without opening the editor.)
   */
  static GIT_PATH_FUNC(rebase_path_fixup_msg, "rebase-merge/message-fixup")
 +/*
 + * This file contains the list fixup/squash commands that have been
 + * accumulated into message-fixup or message-squash so far.
 + */
 +static GIT_PATH_FUNC(rebase_path_current_fixups, "rebase-merge/current-fixups")
  /*
   * A script to set the GIT_AUTHOR_NAME, GIT_AUTHOR_EMAIL, and
   * GIT_AUTHOR_DATE that will be used for the commit that is currently
@@@ -123,6 -125,12 +123,12 @@@ static GIT_PATH_FUNC(rebase_path_rewrit
  static GIT_PATH_FUNC(rebase_path_rewritten_pending,
        "rebase-merge/rewritten-pending")
  
+ /*
+  * The path of the file containig the OID of the "squash onto" commit, i.e.
+  * the dummy commit used for `reset [new root]`.
+  */
+ static GIT_PATH_FUNC(rebase_path_squash_onto, "rebase-merge/squash-onto")
  /*
   * The path of the file listing refs that need to be deleted after the rebase
   * finishes. This is used by the `label` command to record the need for cleanup.
@@@ -277,7 -285,6 +283,7 @@@ int sequencer_remove_state(struct repla
        for (i = 0; i < opts->xopts_nr; i++)
                free(opts->xopts[i]);
        free(opts->xopts);
 +      strbuf_release(&opts->current_fixups);
  
        strbuf_reset(&buf);
        strbuf_addstr(&buf, get_dir(opts));
@@@ -469,7 -476,8 +475,8 @@@ static int fast_forward_to(const struc
        transaction = ref_transaction_begin(&err);
        if (!transaction ||
            ref_transaction_update(transaction, "HEAD",
-                                  to, unborn ? &null_oid : from,
+                                  to, unborn && !is_rebase_i(opts) ?
+                                  &null_oid : from,
                                   0, sb.buf, &err) ||
            ref_transaction_commit(transaction, &err)) {
                ref_transaction_free(transaction);
@@@ -528,8 -536,8 +535,8 @@@ static int do_recursive_merge(struct co
        o.show_rename_progress = 1;
  
        head_tree = parse_tree_indirect(head);
 -      next_tree = next ? next->tree : empty_tree();
 -      base_tree = base ? base->tree : empty_tree();
 +      next_tree = next ? get_commit_tree(next) : empty_tree();
 +      base_tree = base ? get_commit_tree(base) : empty_tree();
  
        for (xopt = opts->xopts; xopt != opts->xopts + opts->xopts_nr; xopt++)
                parse_merge_opt(&o, *xopt);
        return !clean;
  }
  
+ static struct object_id *get_cache_tree_oid(void)
+ {
+       if (!active_cache_tree)
+               active_cache_tree = cache_tree();
+       if (!cache_tree_fully_valid(active_cache_tree))
+               if (cache_tree_update(&the_index, 0)) {
+                       error(_("unable to update cache tree"));
+                       return NULL;
+               }
+       return &active_cache_tree->oid;
+ }
  static int is_index_unchanged(void)
  {
-       struct object_id head_oid;
+       struct object_id head_oid, *cache_tree_oid;
        struct commit *head_commit;
  
        if (!resolve_ref_unsafe("HEAD", RESOLVE_REF_READING, &head_oid, NULL))
        if (parse_commit(head_commit))
                return -1;
  
-       if (!active_cache_tree)
-               active_cache_tree = cache_tree();
-       if (!cache_tree_fully_valid(active_cache_tree))
-               if (cache_tree_update(&the_index, 0))
-                       return error(_("unable to update cache tree"));
+       if (!(cache_tree_oid = get_cache_tree_oid()))
+               return -1;
  
-       return !oidcmp(&active_cache_tree->oid,
-                      get_commit_tree_oid(head_commit));
 -      return !oidcmp(cache_tree_oid, &head_commit->tree->object.oid);
++      return !oidcmp(cache_tree_oid, get_commit_tree_oid(head_commit));
  }
  
  static int write_author_script(const char *message)
@@@ -682,6 -699,52 +698,52 @@@ static char *get_author(const char *mes
        return NULL;
  }
  
+ /* Read author-script and return an ident line (author <email> timestamp) */
+ static const char *read_author_ident(struct strbuf *buf)
+ {
+       const char *keys[] = {
+               "GIT_AUTHOR_NAME=", "GIT_AUTHOR_EMAIL=", "GIT_AUTHOR_DATE="
+       };
+       char *in, *out, *eol;
+       int i = 0, len;
+       if (strbuf_read_file(buf, rebase_path_author_script(), 256) <= 0)
+               return NULL;
+       /* dequote values and construct ident line in-place */
+       for (in = out = buf->buf; i < 3 && in - buf->buf < buf->len; i++) {
+               if (!skip_prefix(in, keys[i], (const char **)&in)) {
+                       warning("could not parse '%s' (looking for '%s'",
+                               rebase_path_author_script(), keys[i]);
+                       return NULL;
+               }
+               eol = strchrnul(in, '\n');
+               *eol = '\0';
+               sq_dequote(in);
+               len = strlen(in);
+               if (i > 0) /* separate values by spaces */
+                       *(out++) = ' ';
+               if (i == 1) /* email needs to be surrounded by <...> */
+                       *(out++) = '<';
+               memmove(out, in, len);
+               out += len;
+               if (i == 1) /* email needs to be surrounded by <...> */
+                       *(out++) = '>';
+               in = eol + 1;
+       }
+       if (i < 3) {
+               warning("could not parse '%s' (looking for '%s')",
+                       rebase_path_author_script(), keys[i]);
+               return NULL;
+       }
+       buf->len = out - buf->buf;
+       return buf->buf;
+ }
  static const char staged_changes_advice[] =
  N_("you have staged changes in your working tree\n"
  "If these changes are meant to be squashed into the previous commit, run:\n"
  #define AMEND_MSG   (1<<2)
  #define CLEANUP_MSG (1<<3)
  #define VERIFY_MSG  (1<<4)
+ #define CREATE_ROOT_COMMIT (1<<5)
  
  /*
   * If we are cherry-pick, and if the merge did not result in
@@@ -720,6 -784,40 +783,40 @@@ static int run_git_commit(const char *d
        struct child_process cmd = CHILD_PROCESS_INIT;
        const char *value;
  
+       if (flags & CREATE_ROOT_COMMIT) {
+               struct strbuf msg = STRBUF_INIT, script = STRBUF_INIT;
+               const char *author = is_rebase_i(opts) ?
+                       read_author_ident(&script) : NULL;
+               struct object_id root_commit, *cache_tree_oid;
+               int res = 0;
+               if (!defmsg)
+                       BUG("root commit without message");
+               if (!(cache_tree_oid = get_cache_tree_oid()))
+                       res = -1;
+               if (!res)
+                       res = strbuf_read_file(&msg, defmsg, 0);
+               if (res <= 0)
+                       res = error_errno(_("could not read '%s'"), defmsg);
+               else
+                       res = commit_tree(msg.buf, msg.len, cache_tree_oid,
+                                         NULL, &root_commit, author,
+                                         opts->gpg_sign);
+               strbuf_release(&msg);
+               strbuf_release(&script);
+               if (!res) {
+                       update_ref(NULL, "CHERRY_PICK_HEAD", &root_commit, NULL,
+                                  REF_NO_DEREF, UPDATE_REFS_MSG_ON_ERR);
+                       res = update_ref(NULL, "HEAD", &root_commit, NULL, 0,
+                                        UPDATE_REFS_MSG_ON_ERR);
+               }
+               return res < 0 ? error(_("writing root commit")) : 0;
+       }
        cmd.git_cmd = 1;
  
        if (is_rebase_i(opts)) {
                argv_array_pushf(&cmd.args, "-S%s", opts->gpg_sign);
        if (defmsg)
                argv_array_pushl(&cmd.args, "-F", defmsg, NULL);
 +      else if (!(flags & EDIT_MSG))
 +              argv_array_pushl(&cmd.args, "-C", "HEAD", NULL);
        if ((flags & CLEANUP_MSG))
                argv_array_push(&cmd.args, "--cleanup=strip");
        if ((flags & EDIT_MSG))
@@@ -1149,7 -1245,7 +1246,7 @@@ static int try_to_commit(struct strbuf 
        }
  
        if (!(flags & ALLOW_EMPTY) && !oidcmp(current_head ?
 -                                            &current_head->tree->object.oid :
 +                                            get_commit_tree_oid(current_head) :
                                              &empty_tree_oid, &tree)) {
                res = 1; /* run 'git commit' to display error message */
                goto out;
                goto out;
        }
  
 +      reset_ident_date();
 +
        if (commit_tree_extended(msg->buf, msg->len, &tree, parents,
                                 oid, author, opts->gpg_sign, extra)) {
                res = error(_("failed to write commit object"));
@@@ -1210,7 -1304,8 +1307,8 @@@ static int do_commit(const char *msg_fi
  {
        int res = 1;
  
-       if (!(flags & EDIT_MSG) && !(flags & VERIFY_MSG)) {
+       if (!(flags & EDIT_MSG) && !(flags & VERIFY_MSG) &&
+           !(flags & CREATE_ROOT_COMMIT)) {
                struct object_id oid;
                struct strbuf sb = STRBUF_INIT;
  
@@@ -1249,12 -1344,12 +1347,12 @@@ static int is_original_commit_empty(str
                if (parse_commit(parent))
                        return error(_("could not parse parent commit %s"),
                                oid_to_hex(&parent->object.oid));
 -              ptree_oid = &parent->tree->object.oid;
 +              ptree_oid = get_commit_tree_oid(parent);
        } else {
                ptree_oid = the_hash_algo->empty_tree; /* commit is root */
        }
  
 -      return !oidcmp(ptree_oid, &commit->tree->object.oid);
 +      return !oidcmp(ptree_oid, get_commit_tree_oid(commit));
  }
  
  /*
@@@ -1363,27 -1458,54 +1461,43 @@@ static int is_fixup(enum todo_command c
        return command == TODO_FIXUP || command == TODO_SQUASH;
  }
  
+ /* Does this command create a (non-merge) commit? */
+ static int is_pick_or_similar(enum todo_command command)
+ {
+       switch (command) {
+       case TODO_PICK:
+       case TODO_REVERT:
+       case TODO_EDIT:
+       case TODO_REWORD:
+       case TODO_FIXUP:
+       case TODO_SQUASH:
+               return 1;
+       default:
+               return 0;
+       }
+ }
  static int update_squash_messages(enum todo_command command,
                struct commit *commit, struct replay_opts *opts)
  {
        struct strbuf buf = STRBUF_INIT;
 -      int count, res;
 +      int res;
        const char *message, *body;
  
 -      if (file_exists(rebase_path_squash_msg())) {
 +      if (opts->current_fixup_count > 0) {
                struct strbuf header = STRBUF_INIT;
 -              char *eol, *p;
 +              char *eol;
  
 -              if (strbuf_read_file(&buf, rebase_path_squash_msg(), 2048) <= 0)
 +              if (strbuf_read_file(&buf, rebase_path_squash_msg(), 9) <= 0)
                        return error(_("could not read '%s'"),
                                rebase_path_squash_msg());
  
 -              p = buf.buf + 1;
 -              eol = strchrnul(buf.buf, '\n');
 -              if (buf.buf[0] != comment_line_char ||
 -                  (p += strcspn(p, "0123456789\n")) == eol)
 -                      return error(_("unexpected 1st line of squash message:"
 -                                     "\n\n\t%.*s"),
 -                                   (int)(eol - buf.buf), buf.buf);
 -              count = strtol(p, NULL, 10);
 -
 -              if (count < 1)
 -                      return error(_("invalid 1st line of squash message:\n"
 -                                     "\n\t%.*s"),
 -                                   (int)(eol - buf.buf), buf.buf);
 +              eol = buf.buf[0] != comment_line_char ?
 +                      buf.buf : strchrnul(buf.buf, '\n');
  
                strbuf_addf(&header, "%c ", comment_line_char);
 -              strbuf_addf(&header,
 -                          _("This is a combination of %d commits."), ++count);
 +              strbuf_addf(&header, _("This is a combination of %d commits."),
 +                          opts->current_fixup_count + 2);
                strbuf_splice(&buf, 0, eol - buf.buf, header.buf, header.len);
                strbuf_release(&header);
        } else {
                                     rebase_path_fixup_msg());
                }
  
 -              count = 2;
                strbuf_addf(&buf, "%c ", comment_line_char);
 -              strbuf_addf(&buf, _("This is a combination of %d commits."),
 -                          count);
 +              strbuf_addf(&buf, _("This is a combination of %d commits."), 2);
                strbuf_addf(&buf, "\n%c ", comment_line_char);
                strbuf_addstr(&buf, _("This is the 1st commit message:"));
                strbuf_addstr(&buf, "\n\n");
        if (command == TODO_SQUASH) {
                unlink(rebase_path_fixup_msg());
                strbuf_addf(&buf, "\n%c ", comment_line_char);
 -              strbuf_addf(&buf, _("This is the commit message #%d:"), count);
 +              strbuf_addf(&buf, _("This is the commit message #%d:"),
 +                          ++opts->current_fixup_count);
                strbuf_addstr(&buf, "\n\n");
                strbuf_addstr(&buf, body);
        } else if (command == TODO_FIXUP) {
                strbuf_addf(&buf, "\n%c ", comment_line_char);
                strbuf_addf(&buf, _("The commit message #%d will be skipped:"),
 -                          count);
 +                          ++opts->current_fixup_count);
                strbuf_addstr(&buf, "\n\n");
                strbuf_add_commented_lines(&buf, body, strlen(body));
        } else
  
        res = write_message(buf.buf, buf.len, rebase_path_squash_msg(), 0);
        strbuf_release(&buf);
 +
 +      if (!res) {
 +              strbuf_addf(&opts->current_fixups, "%s%s %s",
 +                          opts->current_fixups.len ? "\n" : "",
 +                          command_to_string(command),
 +                          oid_to_hex(&commit->object.oid));
 +              res = write_message(opts->current_fixups.buf,
 +                                  opts->current_fixups.len,
 +                                  rebase_path_current_fixups(), 0);
 +      }
 +
        return res;
  }
  
@@@ -1516,7 -1628,14 +1630,14 @@@ static int do_pick_commit(enum todo_com
                        return error(_("your index file is unmerged."));
        } else {
                unborn = get_oid("HEAD", &head);
-               if (unborn)
+               /* Do we want to generate a root commit? */
+               if (is_pick_or_similar(command) && opts->have_squash_onto &&
+                   !oidcmp(&head, &opts->squash_onto)) {
+                       if (is_fixup(command))
+                               return error(_("cannot fixup root commit"));
+                       flags |= CREATE_ROOT_COMMIT;
+                       unborn = 1;
+               } else if (unborn)
                        oidcpy(&head, the_hash_algo->empty_tree);
                if (index_differs_from(unborn ? EMPTY_TREE_SHA1_HEX : "HEAD",
                                       NULL, 0))
@@@ -1713,9 -1832,6 +1834,9 @@@ fast_forward_edit
        if (!res && final_fixup) {
                unlink(rebase_path_fixup_msg());
                unlink(rebase_path_squash_msg());
 +              unlink(rebase_path_current_fixups());
 +              strbuf_reset(&opts->current_fixups);
 +              opts->current_fixup_count = 0;
        }
  
  leave:
@@@ -2132,16 -2248,12 +2253,22 @@@ static int read_populate_opts(struct re
                read_strategy_opts(opts, &buf);
                strbuf_release(&buf);
  
 +              if (read_oneliner(&opts->current_fixups,
 +                                rebase_path_current_fixups(), 1)) {
 +                      const char *p = opts->current_fixups.buf;
 +                      opts->current_fixup_count = 1;
 +                      while ((p = strchr(p, '\n'))) {
 +                              opts->current_fixup_count++;
 +                              p++;
 +                      }
 +              }
 +
+               if (read_oneliner(&buf, rebase_path_squash_onto(), 0)) {
+                       if (get_oid_hex(buf.buf, &opts->squash_onto) < 0)
+                               return error(_("unusable squash-onto"));
+                       opts->have_squash_onto = 1;
+               }
                return 0;
        }
  
@@@ -2486,9 -2598,10 +2613,9 @@@ static int error_with_patch(struct comm
  static int error_failed_squash(struct commit *commit,
        struct replay_opts *opts, int subject_len, const char *subject)
  {
 -      if (rename(rebase_path_squash_msg(), rebase_path_message()))
 -              return error(_("could not rename '%s' to '%s'"),
 +      if (copy_file(rebase_path_message(), rebase_path_squash_msg(), 0666))
 +              return error(_("could not copy '%s' to '%s'"),
                        rebase_path_squash_msg(), rebase_path_message());
 -      unlink(rebase_path_fixup_msg());
        unlink(git_path_merge_msg());
        if (copy_file(git_path_merge_msg(), rebase_path_message(), 0666))
                return error(_("could not copy '%s' to '%s'"),
@@@ -2580,7 -2693,7 +2707,7 @@@ static int safe_append(const char *file
  
  static int do_label(const char *name, int len)
  {
 -      struct ref_store *refs = get_main_ref_store();
 +      struct ref_store *refs = get_main_ref_store(the_repository);
        struct ref_transaction *transaction;
        struct strbuf ref_name = STRBUF_INIT, err = STRBUF_INIT;
        struct strbuf msg = STRBUF_INIT;
@@@ -2634,18 -2747,34 +2761,34 @@@ static int do_reset(const char *name, i
        if (hold_locked_index(&lock, LOCK_REPORT_ON_ERROR) < 0)
                return -1;
  
-       /* Determine the length of the label */
-       for (i = 0; i < len; i++)
-               if (isspace(name[i]))
-                       len = i;
-       strbuf_addf(&ref_name, "refs/rewritten/%.*s", len, name);
-       if (get_oid(ref_name.buf, &oid) &&
-           get_oid(ref_name.buf + strlen("refs/rewritten/"), &oid)) {
-               error(_("could not read '%s'"), ref_name.buf);
-               rollback_lock_file(&lock);
-               strbuf_release(&ref_name);
-               return -1;
+       if (len == 10 && !strncmp("[new root]", name, len)) {
+               if (!opts->have_squash_onto) {
+                       const char *hex;
+                       if (commit_tree("", 0, the_hash_algo->empty_tree,
+                                       NULL, &opts->squash_onto,
+                                       NULL, NULL))
+                               return error(_("writing fake root commit"));
+                       opts->have_squash_onto = 1;
+                       hex = oid_to_hex(&opts->squash_onto);
+                       if (write_message(hex, strlen(hex),
+                                         rebase_path_squash_onto(), 0))
+                               return error(_("writing squash-onto"));
+               }
+               oidcpy(&oid, &opts->squash_onto);
+       } else {
+               /* Determine the length of the label */
+               for (i = 0; i < len; i++)
+                       if (isspace(name[i]))
+                               len = i;
+               strbuf_addf(&ref_name, "refs/rewritten/%.*s", len, name);
+               if (get_oid(ref_name.buf, &oid) &&
+                   get_oid(ref_name.buf + strlen("refs/rewritten/"), &oid)) {
+                       error(_("could not read '%s'"), ref_name.buf);
+                       rollback_lock_file(&lock);
+                       strbuf_release(&ref_name);
+                       return -1;
+               }
        }
  
        memset(&unpack_tree_opts, 0, sizeof(unpack_tree_opts));
@@@ -2741,6 -2870,18 +2884,18 @@@ static int do_merge(struct commit *comm
                goto leave_merge;
        }
  
+       if (opts->have_squash_onto &&
+           !oidcmp(&head_commit->object.oid, &opts->squash_onto)) {
+               /*
+                * When the user tells us to "merge" something into a
+                * "[new root]", let's simply fast-forward to the merge head.
+                */
+               rollback_lock_file(&lock);
+               ret = fast_forward_to(&merge_commit->object.oid,
+                                      &head_commit->object.oid, 0, opts);
+               goto leave_merge;
+       }
        if (commit) {
                const char *message = get_commit_buffer(commit, NULL);
                const char *body;
@@@ -3248,16 -3389,19 +3403,16 @@@ static int continue_single_pick(void
        return run_command_v_opt(argv, RUN_GIT_CMD);
  }
  
 -static int commit_staged_changes(struct replay_opts *opts)
 +static int commit_staged_changes(struct replay_opts *opts,
 +                               struct todo_list *todo_list)
  {
        unsigned int flags = ALLOW_EMPTY | EDIT_MSG;
 +      unsigned int final_fixup = 0, is_clean;
  
        if (has_unstaged_changes(1))
                return error(_("cannot rebase: You have unstaged changes."));
 -      if (!has_uncommitted_changes(0)) {
 -              const char *cherry_pick_head = git_path_cherry_pick_head();
  
 -              if (file_exists(cherry_pick_head) && unlink(cherry_pick_head))
 -                      return error(_("could not remove CHERRY_PICK_HEAD"));
 -              return 0;
 -      }
 +      is_clean = !has_uncommitted_changes(0);
  
        if (file_exists(rebase_path_amend())) {
                struct strbuf rev = STRBUF_INIT;
                if (get_oid_hex(rev.buf, &to_amend))
                        return error(_("invalid contents: '%s'"),
                                rebase_path_amend());
 -              if (oidcmp(&head, &to_amend))
 +              if (!is_clean && oidcmp(&head, &to_amend))
                        return error(_("\nYou have uncommitted changes in your "
                                       "working tree. Please, commit them\n"
                                       "first and then run 'git rebase "
                                       "--continue' again."));
 +              /*
 +               * When skipping a failed fixup/squash, we need to edit the
 +               * commit message, the current fixup list and count, and if it
 +               * was the last fixup/squash in the chain, we need to clean up
 +               * the commit message and if there was a squash, let the user
 +               * edit it.
 +               */
 +              if (is_clean && !oidcmp(&head, &to_amend) &&
 +                  opts->current_fixup_count > 0 &&
 +                  file_exists(rebase_path_stopped_sha())) {
 +                      const char *p = opts->current_fixups.buf;
 +                      int len = opts->current_fixups.len;
 +
 +                      opts->current_fixup_count--;
 +                      if (!len)
 +                              BUG("Incorrect current_fixups:\n%s", p);
 +                      while (len && p[len - 1] != '\n')
 +                              len--;
 +                      strbuf_setlen(&opts->current_fixups, len);
 +                      if (write_message(p, len, rebase_path_current_fixups(),
 +                                        0) < 0)
 +                              return error(_("could not write file: '%s'"),
 +                                           rebase_path_current_fixups());
 +
 +                      /*
 +                       * If a fixup/squash in a fixup/squash chain failed, the
 +                       * commit message is already correct, no need to commit
 +                       * it again.
 +                       *
 +                       * Only if it is the final command in the fixup/squash
 +                       * chain, and only if the chain is longer than a single
 +                       * fixup/squash command (which was just skipped), do we
 +                       * actually need to re-commit with a cleaned up commit
 +                       * message.
 +                       */
 +                      if (opts->current_fixup_count > 0 &&
 +                          !is_fixup(peek_command(todo_list, 0))) {
 +                              final_fixup = 1;
 +                              /*
 +                               * If there was not a single "squash" in the
 +                               * chain, we only need to clean up the commit
 +                               * message, no need to bother the user with
 +                               * opening the commit message in the editor.
 +                               */
 +                              if (!starts_with(p, "squash ") &&
 +                                  !strstr(p, "\nsquash "))
 +                                      flags = (flags & ~EDIT_MSG) | CLEANUP_MSG;
 +                      } else if (is_fixup(peek_command(todo_list, 0))) {
 +                              /*
 +                               * We need to update the squash message to skip
 +                               * the latest commit message.
 +                               */
 +                              struct commit *commit;
 +                              const char *path = rebase_path_squash_msg();
 +
 +                              if (parse_head(&commit) ||
 +                                  !(p = get_commit_buffer(commit, NULL)) ||
 +                                  write_message(p, strlen(p), path, 0)) {
 +                                      unuse_commit_buffer(commit, p);
 +                                      return error(_("could not write file: "
 +                                                     "'%s'"), path);
 +                              }
 +                              unuse_commit_buffer(commit, p);
 +                      }
 +              }
  
                strbuf_release(&rev);
                flags |= AMEND_MSG;
        }
  
 -      if (run_git_commit(rebase_path_message(), opts, flags))
 +      if (is_clean) {
 +              const char *cherry_pick_head = git_path_cherry_pick_head();
 +
 +              if (file_exists(cherry_pick_head) && unlink(cherry_pick_head))
 +                      return error(_("could not remove CHERRY_PICK_HEAD"));
 +              if (!final_fixup)
 +                      return 0;
 +      }
 +
 +      if (run_git_commit(final_fixup ? NULL : rebase_path_message(),
 +                         opts, flags))
                return error(_("could not commit staged changes."));
        unlink(rebase_path_amend());
 +      if (final_fixup) {
 +              unlink(rebase_path_fixup_msg());
 +              unlink(rebase_path_squash_msg());
 +      }
 +      if (opts->current_fixup_count > 0) {
 +              /*
 +               * Whether final fixup or not, we just cleaned up the commit
 +               * message...
 +               */
 +              unlink(rebase_path_current_fixups());
 +              strbuf_reset(&opts->current_fixups);
 +              opts->current_fixup_count = 0;
 +      }
        return 0;
  }
  
@@@ -3382,16 -3438,14 +3537,16 @@@ int sequencer_continue(struct replay_op
        if (read_and_refresh_cache(opts))
                return -1;
  
 +      if (read_populate_opts(opts))
 +              return -1;
        if (is_rebase_i(opts)) {
 -              if (commit_staged_changes(opts))
 +              if ((res = read_populate_todo(&todo_list, opts)))
 +                      goto release_todo_list;
 +              if (commit_staged_changes(opts, &todo_list))
                        return -1;
        } else if (!file_exists(get_todo_path(opts)))
                return continue_single_pick();
 -      if (read_populate_opts(opts))
 -              return -1;
 -      if ((res = read_populate_todo(&todo_list, opts)))
 +      else if ((res = read_populate_todo(&todo_list, opts)))
                goto release_todo_list;
  
        if (!is_rebase_i(opts)) {
@@@ -3450,8 -3504,7 +3605,8 @@@ int sequencer_pick_revisions(struct rep
  
                if (!get_oid(name, &oid)) {
                        if (!lookup_commit_reference_gently(&oid, 1)) {
 -                              enum object_type type = oid_object_info(&oid,
 +                              enum object_type type = oid_object_info(the_repository,
 +                                                                      &oid,
                                                                        NULL);
                                return error(_("%s: can't cherry-pick a %s"),
                                        name, type_name(type));
@@@ -3850,7 -3903,8 +4005,8 @@@ static int make_script_with_merges(stru
                }
  
                if (!commit)
-                       fprintf(out, "%s onto\n", cmd_reset);
+                       fprintf(out, "%s %s\n", cmd_reset,
+                               rebase_cousins ? "onto" : "[new root]");
                else {
                        const char *to = NULL;
  
diff --combined sequencer.h
index a800cb57558fab14d43cda47c9a69b3c5015e1a8,4b2717881fa1c6f5011cddd6a5f1c28761d8e8ca..c5787c6b566bbc89caad1a099f4281fecba01766
@@@ -44,14 -44,14 +44,18 @@@ struct replay_opts 
        char **xopts;
        size_t xopts_nr, xopts_alloc;
  
 +      /* Used by fixup/squash */
 +      struct strbuf current_fixups;
 +      int current_fixup_count;
 +
+       /* placeholder commit for -i --root */
+       struct object_id squash_onto;
+       int have_squash_onto;
        /* Only used by REPLAY_NONE */
        struct rev_info *revs;
  };
 -#define REPLAY_OPTS_INIT { -1 }
 +#define REPLAY_OPTS_INIT { .action = -1, .current_fixups = STRBUF_INIT }
  
  /* Call this to setup defaults before parsing command line options */
  void sequencer_init_config(struct replay_opts *opts);