Merge branch 'pw/rebase-i-merge-segv-fix'
[git/git.git] / sequencer.c
index df49199..65d371c 100644 (file)
@@ -2,6 +2,7 @@
 #include "config.h"
 #include "lockfile.h"
 #include "dir.h"
+#include "object-store.h"
 #include "object.h"
 #include "commit.h"
 #include "sequencer.h"
@@ -27,6 +28,7 @@
 #include "worktree.h"
 #include "oidmap.h"
 #include "oidset.h"
+#include "commit-slab.h"
 #include "alias.h"
 
 #define GIT_REFLOG_ACTION "GIT_REFLOG_ACTION"
@@ -61,12 +63,12 @@ static GIT_PATH_FUNC(rebase_path_done, "rebase-merge/done")
  * The file to keep track of how many commands were already processed (e.g.
  * for the prompt).
  */
-static GIT_PATH_FUNC(rebase_path_msgnum, "rebase-merge/msgnum");
+static GIT_PATH_FUNC(rebase_path_msgnum, "rebase-merge/msgnum")
 /*
  * The file to keep track of how many commands are to be processed in total
  * (e.g. for the prompt).
  */
-static GIT_PATH_FUNC(rebase_path_msgtotal, "rebase-merge/end");
+static GIT_PATH_FUNC(rebase_path_msgtotal, "rebase-merge/end")
 /*
  * The commit message that is planned to be used for any changes that
  * need to be committed following a user interaction.
@@ -175,6 +177,7 @@ static int git_sequencer_config(const char *k, const char *v, void *cb)
                        warning(_("invalid commit message cleanup mode '%s'"),
                                  s);
 
+               free((char *)s);
                return status;
        }
 
@@ -304,7 +307,7 @@ static const char *action_name(const struct replay_opts *opts)
        case REPLAY_INTERACTIVE_REBASE:
                return N_("rebase -i");
        }
-       die(_("Unknown action: %d"), opts->action);
+       die(_("unknown action: %d"), opts->action);
 }
 
 struct commit_message {
@@ -355,7 +358,7 @@ static void print_advice(int show_hint, struct replay_opts *opts)
                 * (typically rebase --interactive) wants to take care
                 * of the commit itself so remove CHERRY_PICK_HEAD
                 */
-               unlink(git_path_cherry_pick_head());
+               unlink(git_path_cherry_pick_head(the_repository));
                return;
        }
 
@@ -430,7 +433,7 @@ static int read_oneliner(struct strbuf *buf,
 
 static struct tree *empty_tree(void)
 {
-       return lookup_tree(the_hash_algo->empty_tree);
+       return lookup_tree(the_repository, the_repository->hash_algo->empty_tree);
 }
 
 static int error_dirty_index(struct replay_opts *opts)
@@ -591,7 +594,7 @@ static int is_index_unchanged(void)
        if (!resolve_ref_unsafe("HEAD", RESOLVE_REF_READING, &head_oid, NULL))
                return error(_("could not resolve HEAD commit"));
 
-       head_commit = lookup_commit(&head_oid);
+       head_commit = lookup_commit(the_repository, &head_oid);
 
        /*
         * If head_commit is NULL, check_commit, called from
@@ -651,6 +654,7 @@ missing_author:
                        strbuf_addch(&buf, *(message++));
                else
                        strbuf_addf(&buf, "'\\\\%c'", *(message++));
+       strbuf_addch(&buf, '\'');
        res = write_message(buf.buf, buf.len, rebase_path_author_script(), 1);
        strbuf_release(&buf);
        return res;
@@ -705,43 +709,51 @@ 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;
+       struct strbuf out = STRBUF_INIT;
+       char *in, *eol;
+       const char *val[3];
+       int i = 0;
 
        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++) {
+       for (in = 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'",
+                       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++) = '>';
+               if (!sq_dequote(in)) {
+                       warning(_("bad quoting on %s value in '%s'"),
+                               keys[i], rebase_path_author_script());
+                       return NULL;
+               }
+               val[i] = in;
                in = eol + 1;
        }
 
        if (i < 3) {
-               warning("could not parse '%s' (looking for '%s')",
+               warning(_("could not parse '%s' (looking for '%s')"),
                        rebase_path_author_script(), keys[i]);
                return NULL;
        }
 
-       buf->len = out - buf->buf;
+       /* validate date since fmt_ident() will die() on bad value */
+       if (parse_date(val[2], &out)){
+               warning(_("invalid date format '%s' in '%s'"),
+                       val[2], rebase_path_author_script());
+               strbuf_release(&out);
+               return NULL;
+       }
+
+       strbuf_reset(&out);
+       strbuf_addstr(&out, fmt_ident(val[0], val[1], val[2], 0));
+       strbuf_swap(buf, &out);
+       strbuf_release(&out);
        return buf->buf;
 }
 
@@ -1098,7 +1110,7 @@ void print_commit_summary(const char *prefix, const struct object_id *oid,
        struct strbuf author_ident = STRBUF_INIT;
        struct strbuf committer_ident = STRBUF_INIT;
 
-       commit = lookup_commit(oid);
+       commit = lookup_commit(the_repository, oid);
        if (!commit)
                die(_("couldn't look up newly created commit"));
        if (parse_commit(commit))
@@ -1173,7 +1185,7 @@ static int parse_head(struct commit **head)
        if (get_oid("HEAD", &oid)) {
                current_head = NULL;
        } else {
-               current_head = lookup_commit_reference(&oid);
+               current_head = lookup_commit_reference(the_repository, &oid);
                if (!current_head)
                        return error(_("could not parse HEAD"));
                if (oidcmp(&oid, &current_head->object.oid)) {
@@ -1241,7 +1253,7 @@ static int try_to_commit(struct strbuf *msg, const char *author,
                commit_list_insert(current_head, &parents);
        }
 
-       if (write_cache_as_tree(&tree, 0, NULL)) {
+       if (write_index_as_tree(&tree, &the_index, get_index_file(), 0, NULL)) {
                res = error(_("git write-tree failed to write a tree"));
                goto out;
        }
@@ -1322,8 +1334,8 @@ static int do_commit(const char *msg_file, const char *author,
                                    &oid);
                strbuf_release(&sb);
                if (!res) {
-                       unlink(git_path_cherry_pick_head());
-                       unlink(git_path_merge_msg());
+                       unlink(git_path_cherry_pick_head(the_repository));
+                       unlink(git_path_merge_msg(the_repository));
                        if (!is_rebase_i(opts))
                                print_commit_summary(NULL, &oid,
                                                SUMMARY_SHOW_AUTHOR_DATE);
@@ -1442,7 +1454,7 @@ static const char *command_to_string(const enum todo_command command)
 {
        if (command < TODO_COMMENT)
                return todo_command_info[command].str;
-       die("Unknown command: %d", command);
+       die(_("unknown command: %d"), command);
 }
 
 static char command_to_char(const enum todo_command command)
@@ -1508,7 +1520,7 @@ static int update_squash_messages(enum todo_command command,
 
                if (get_oid("HEAD", &head))
                        return error(_("need a HEAD to fixup"));
-               if (!(head_commit = lookup_commit_reference(&head)))
+               if (!(head_commit = lookup_commit_reference(the_repository, &head)))
                        return error(_("could not read HEAD"));
                if (!(head_message = get_commit_buffer(head_commit, NULL)))
                        return error(_("could not read HEAD's commit message"));
@@ -1540,13 +1552,13 @@ static int update_squash_messages(enum todo_command command,
                unlink(rebase_path_fixup_msg());
                strbuf_addf(&buf, "\n%c ", comment_line_char);
                strbuf_addf(&buf, _("This is the commit message #%d:"),
-                           ++opts->current_fixup_count);
+                           ++opts->current_fixup_count + 1);
                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:"),
-                           ++opts->current_fixup_count);
+                           ++opts->current_fixup_count + 1);
                strbuf_addstr(&buf, "\n\n");
                strbuf_add_commented_lines(&buf, body, strlen(body));
        } else
@@ -1611,7 +1623,7 @@ static int do_pick_commit(enum todo_command command, struct commit *commit,
                struct replay_opts *opts, int final_fixup)
 {
        unsigned int flags = opts->edit ? EDIT_MSG : 0;
-       const char *msg_file = opts->edit ? NULL : git_path_merge_msg();
+       const char *msg_file = opts->edit ? NULL : git_path_merge_msg(the_repository);
        struct object_id head;
        struct commit *base, *next, *parent;
        const char *base_label, *next_label;
@@ -1627,7 +1639,7 @@ static int do_pick_commit(enum todo_command command, struct commit *commit,
                 * that represents the "current" state for merge-recursive
                 * to work on.
                 */
-               if (write_cache_as_tree(&head, 0, NULL))
+               if (write_index_as_tree(&head, &the_index, get_index_file(), 0, NULL))
                        return error(_("your index file is unmerged."));
        } else {
                unborn = get_oid("HEAD", &head);
@@ -1753,12 +1765,12 @@ static int do_pick_commit(enum todo_command command, struct commit *commit,
                        flags |= CLEANUP_MSG;
                        msg_file = rebase_path_fixup_msg();
                } else {
-                       const char *dest = git_path_squash_msg();
+                       const char *dest = git_path_squash_msg(the_repository);
                        unlink(dest);
                        if (copy_file(dest, rebase_path_squash_msg(), 0666))
                                return error(_("could not rename '%s' to '%s'"),
                                             rebase_path_squash_msg(), dest);
-                       unlink(git_path_merge_msg());
+                       unlink(git_path_merge_msg(the_repository));
                        msg_file = dest;
                        flags |= EDIT_MSG;
                }
@@ -1773,15 +1785,16 @@ static int do_pick_commit(enum todo_command command, struct commit *commit,
                res = do_recursive_merge(base, next, base_label, next_label,
                                         &head, &msgbuf, opts);
                if (res < 0)
-                       return res;
+                       goto leave;
+
                res |= write_message(msgbuf.buf, msgbuf.len,
-                                    git_path_merge_msg(), 0);
+                                    git_path_merge_msg(the_repository), 0);
        } else {
                struct commit_list *common = NULL;
                struct commit_list *remotes = NULL;
 
                res = write_message(msgbuf.buf, msgbuf.len,
-                                   git_path_merge_msg(), 0);
+                                   git_path_merge_msg(the_repository), 0);
 
                commit_list_insert(base, &common);
                commit_list_insert(next, &remotes);
@@ -1860,8 +1873,6 @@ static int prepare_revs(struct replay_opts *opts)
        if (prepare_revision_walk(opts->revs))
                return error(_("revision walk setup failed"));
 
-       if (!opts->revs->commits)
-               return error(_("empty commit set passed"));
        return 0;
 }
 
@@ -2005,7 +2016,7 @@ static int parse_insn_line(struct todo_item *item, const char *bol, char *eol)
        if (status < 0)
                return -1;
 
-       item->commit = lookup_commit_reference(&commit_oid);
+       item->commit = lookup_commit_reference(the_repository, &commit_oid);
        return !item->commit;
 }
 
@@ -2203,6 +2214,7 @@ static int populate_opts_cb(const char *key, const char *value, void *data)
 static void read_strategy_opts(struct replay_opts *opts, struct strbuf *buf)
 {
        int i;
+       char *strategy_opts_string;
 
        strbuf_reset(buf);
        if (!read_oneliner(buf, rebase_path_strategy(), 0))
@@ -2211,7 +2223,11 @@ static void read_strategy_opts(struct replay_opts *opts, struct strbuf *buf)
        if (!read_oneliner(buf, rebase_path_strategy_opts(), 0))
                return;
 
-       opts->xopts_nr = split_cmdline(buf->buf, (const char ***)&opts->xopts);
+       strategy_opts_string = buf->buf;
+       if (*strategy_opts_string == ' ')
+               strategy_opts_string++;
+       opts->xopts_nr = split_cmdline(strategy_opts_string,
+                                      (const char ***)&opts->xopts);
        for (i = 0; i < opts->xopts_nr; i++) {
                const char *arg = opts->xopts[i];
 
@@ -2314,6 +2330,10 @@ static int walk_revs_populate_todo(struct todo_list *todo_list,
                        short_commit_name(commit), subject_len, subject);
                unuse_commit_buffer(commit, commit_buffer);
        }
+
+       if (!todo_list->nr)
+               return error(_("empty commit set passed"));
+
        return 0;
 }
 
@@ -2391,8 +2411,8 @@ static int rollback_single_pick(void)
 {
        struct object_id head_oid;
 
-       if (!file_exists(git_path_cherry_pick_head()) &&
-           !file_exists(git_path_revert_head()))
+       if (!file_exists(git_path_cherry_pick_head(the_repository)) &&
+           !file_exists(git_path_revert_head(the_repository)))
                return error(_("no cherry-pick or revert in progress"));
        if (read_ref_full("HEAD", 0, &head_oid, NULL))
                return error(_("cannot resolve HEAD"));
@@ -2593,33 +2613,35 @@ static int error_with_patch(struct commit *commit,
        if (commit) {
                if (make_patch(commit, opts))
                        return -1;
-       } else if (copy_file(rebase_path_message(), git_path_merge_msg(), 0666))
+       } else if (copy_file(rebase_path_message(),
+                            git_path_merge_msg(the_repository), 0666))
                return error(_("unable to copy '%s' to '%s'"),
-                            git_path_merge_msg(), rebase_path_message());
+                            git_path_merge_msg(the_repository), rebase_path_message());
 
        if (to_amend) {
                if (intend_to_amend())
                        return -1;
 
-               fprintf(stderr, "You can amend the commit now, with\n"
-                       "\n"
-                       "  git commit --amend %s\n"
-                       "\n"
-                       "Once you are satisfied with your changes, run\n"
-                       "\n"
-                       "  git rebase --continue\n", gpg_sign_opt_quoted(opts));
+               fprintf(stderr,
+                       _("You can amend the commit now, with\n"
+                         "\n"
+                         "  git commit --amend %s\n"
+                         "\n"
+                         "Once you are satisfied with your changes, run\n"
+                         "\n"
+                         "  git rebase --continue\n"),
+                       gpg_sign_opt_quoted(opts));
        } else if (exit_code) {
                if (commit)
-                       fprintf(stderr, "Could not apply %s... %.*s\n",
-                               short_commit_name(commit),
-                               subject_len, subject);
+                       fprintf_ln(stderr, _("Could not apply %s... %.*s"),
+                                  short_commit_name(commit), subject_len, subject);
                else
                        /*
                         * We don't have the hash of the parent so
                         * just print the line from the todo file.
                         */
-                       fprintf(stderr, "Could not merge %.*s\n",
-                               subject_len, subject);
+                       fprintf_ln(stderr, _("Could not merge %.*s"),
+                                  subject_len, subject);
        }
 
        return exit_code;
@@ -2631,10 +2653,11 @@ static int error_failed_squash(struct commit *commit,
        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(git_path_merge_msg());
-       if (copy_file(git_path_merge_msg(), rebase_path_message(), 0666))
+       unlink(git_path_merge_msg(the_repository));
+       if (copy_file(git_path_merge_msg(the_repository), rebase_path_message(), 0666))
                return error(_("could not copy '%s' to '%s'"),
-                            rebase_path_message(), git_path_merge_msg());
+                            rebase_path_message(),
+                            git_path_merge_msg(the_repository));
        return error_with_patch(commit, subject, subject_len, opts, 1, 0);
 }
 
@@ -2647,6 +2670,8 @@ static int do_exec(const char *command_line)
        fprintf(stderr, "Executing: %s\n", command_line);
        child_argv[0] = command_line;
        argv_array_pushf(&child_env, "GIT_DIR=%s", absolute_path(get_git_dir()));
+       argv_array_pushf(&child_env, "GIT_WORK_TREE=%s",
+                        absolute_path(get_git_work_tree()));
        status = run_command_v_opt_cd_env(child_argv, RUN_USING_SHELL, NULL,
                                          child_env.argv);
 
@@ -2730,7 +2755,7 @@ static int do_label(const char *name, int len)
        struct object_id head_oid;
 
        if (len == 1 && *name == '#')
-               return error("Illegal label name: '%.*s'", len, name);
+               return error(_("illegal label name: '%.*s'"), len, name);
 
        strbuf_addf(&ref_name, "refs/rewritten/%.*s", len, name);
        strbuf_addf(&msg, "rebase -i (label) '%.*s'", len, name);
@@ -2852,6 +2877,26 @@ static int do_reset(const char *name, int len, struct replay_opts *opts)
        return ret;
 }
 
+static struct commit *lookup_label(const char *label, int len,
+                                  struct strbuf *buf)
+{
+       struct commit *commit;
+
+       strbuf_reset(buf);
+       strbuf_addf(buf, "refs/rewritten/%.*s", len, label);
+       commit = lookup_commit_reference_by_name(buf->buf);
+       if (!commit) {
+               /* fall back to non-rewritten ref or commit */
+               strbuf_splice(buf, 0, strlen("refs/rewritten/"), "", 0);
+               commit = lookup_commit_reference_by_name(buf->buf);
+       }
+
+       if (!commit)
+               error(_("could not resolve '%s'"), buf->buf);
+
+       return commit;
+}
+
 static int do_merge(struct commit *commit, const char *arg, int arg_len,
                    int flags, struct replay_opts *opts)
 {
@@ -2860,8 +2905,9 @@ static int do_merge(struct commit *commit, const char *arg, int arg_len,
        struct strbuf ref_name = STRBUF_INIT;
        struct commit *head_commit, *merge_commit, *i;
        struct commit_list *bases, *j, *reversed = NULL;
+       struct commit_list *to_merge = NULL, **tail = &to_merge;
        struct merge_options o;
-       int merge_arg_len, oneline_offset, can_fast_forward, ret;
+       int merge_arg_len, oneline_offset, can_fast_forward, ret, k;
        static struct lock_file lock;
        const char *p;
 
@@ -2876,26 +2922,34 @@ static int do_merge(struct commit *commit, const char *arg, int arg_len,
                goto leave_merge;
        }
 
-       oneline_offset = arg_len;
-       merge_arg_len = strcspn(arg, " \t\n");
-       p = arg + merge_arg_len;
-       p += strspn(p, " \t\n");
-       if (*p == '#' && (!p[1] || isspace(p[1]))) {
-               p += 1 + strspn(p + 1, " \t\n");
-               oneline_offset = p - arg;
-       } else if (p - arg < arg_len)
-               BUG("octopus merges are not supported yet: '%s'", p);
-
-       strbuf_addf(&ref_name, "refs/rewritten/%.*s", merge_arg_len, arg);
-       merge_commit = lookup_commit_reference_by_name(ref_name.buf);
-       if (!merge_commit) {
-               /* fall back to non-rewritten ref or commit */
-               strbuf_splice(&ref_name, 0, strlen("refs/rewritten/"), "", 0);
-               merge_commit = lookup_commit_reference_by_name(ref_name.buf);
+       /*
+        * For octopus merges, the arg starts with the list of revisions to be
+        * merged. The list is optionally followed by '#' and the oneline.
+        */
+       merge_arg_len = oneline_offset = arg_len;
+       for (p = arg; p - arg < arg_len; p += strspn(p, " \t\n")) {
+               if (!*p)
+                       break;
+               if (*p == '#' && (!p[1] || isspace(p[1]))) {
+                       p += 1 + strspn(p + 1, " \t\n");
+                       oneline_offset = p - arg;
+                       break;
+               }
+               k = strcspn(p, " \t\n");
+               if (!k)
+                       continue;
+               merge_commit = lookup_label(p, k, &ref_name);
+               if (!merge_commit) {
+                       ret = error(_("unable to parse '%.*s'"), k, p);
+                       goto leave_merge;
+               }
+               tail = &commit_list_insert(merge_commit, tail)->next;
+               p += k;
+               merge_arg_len = p - arg;
        }
 
-       if (!merge_commit) {
-               ret = error(_("could not resolve '%s'"), ref_name.buf);
+       if (!to_merge) {
+               ret = error(_("nothing to merge: '%.*s'"), arg_len, arg);
                goto leave_merge;
        }
 
@@ -2906,8 +2960,13 @@ static int do_merge(struct commit *commit, const char *arg, int arg_len,
                 * "[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);
+               if (to_merge->next)
+                       ret = error(_("octopus merge cannot be executed on "
+                                     "top of a [new root]"));
+               else
+                       ret = fast_forward_to(&to_merge->item->object.oid,
+                                             &head_commit->object.oid, 0,
+                                             opts);
                goto leave_merge;
        }
 
@@ -2924,11 +2983,11 @@ static int do_merge(struct commit *commit, const char *arg, int arg_len,
                write_author_script(message);
                find_commit_subject(message, &body);
                len = strlen(body);
-               ret = write_message(body, len, git_path_merge_msg(), 0);
+               ret = write_message(body, len, git_path_merge_msg(the_repository), 0);
                unuse_commit_buffer(commit, message);
                if (ret) {
                        error_errno(_("could not write '%s'"),
-                                   git_path_merge_msg());
+                                   git_path_merge_msg(the_repository));
                        goto leave_merge;
                }
        } else {
@@ -2943,17 +3002,18 @@ static int do_merge(struct commit *commit, const char *arg, int arg_len,
                        p = arg + oneline_offset;
                        len = arg_len - oneline_offset;
                } else {
-                       strbuf_addf(&buf, "Merge branch '%.*s'",
+                       strbuf_addf(&buf, "Merge %s '%.*s'",
+                                   to_merge->next ? "branches" : "branch",
                                    merge_arg_len, arg);
                        p = buf.buf;
                        len = buf.len;
                }
 
-               ret = write_message(p, len, git_path_merge_msg(), 0);
+               ret = write_message(p, len, git_path_merge_msg(the_repository), 0);
                strbuf_release(&buf);
                if (ret) {
                        error_errno(_("could not write '%s'"),
-                                   git_path_merge_msg());
+                                   git_path_merge_msg(the_repository));
                        goto leave_merge;
                }
        }
@@ -2967,31 +3027,79 @@ static int do_merge(struct commit *commit, const char *arg, int arg_len,
                        &head_commit->object.oid);
 
        /*
-        * If the merge head is different from the original one, we cannot
+        * If any merge head is different from the original one, we cannot
         * fast-forward.
         */
        if (can_fast_forward) {
-               struct commit_list *second_parent = commit->parents->next;
+               struct commit_list *p = commit->parents->next;
 
-               if (second_parent && !second_parent->next &&
-                   oidcmp(&merge_commit->object.oid,
-                          &second_parent->item->object.oid))
+               for (j = to_merge; j && p; j = j->next, p = p->next)
+                       if (oidcmp(&j->item->object.oid,
+                                  &p->item->object.oid)) {
+                               can_fast_forward = 0;
+                               break;
+                       }
+               /*
+                * If the number of merge heads differs from the original merge
+                * commit, we cannot fast-forward.
+                */
+               if (j || p)
                        can_fast_forward = 0;
        }
 
-       if (can_fast_forward && commit->parents->next &&
-           !commit->parents->next->next &&
-           !oidcmp(&commit->parents->next->item->object.oid,
-                   &merge_commit->object.oid)) {
+       if (can_fast_forward) {
                rollback_lock_file(&lock);
                ret = fast_forward_to(&commit->object.oid,
                                      &head_commit->object.oid, 0, opts);
                goto leave_merge;
        }
 
+       if (to_merge->next) {
+               /* Octopus merge */
+               struct child_process cmd = CHILD_PROCESS_INIT;
+
+               if (read_env_script(&cmd.env_array)) {
+                       const char *gpg_opt = gpg_sign_opt_quoted(opts);
+
+                       ret = error(_(staged_changes_advice), gpg_opt, gpg_opt);
+                       goto leave_merge;
+               }
+
+               cmd.git_cmd = 1;
+               argv_array_push(&cmd.args, "merge");
+               argv_array_push(&cmd.args, "-s");
+               argv_array_push(&cmd.args, "octopus");
+               argv_array_push(&cmd.args, "--no-edit");
+               argv_array_push(&cmd.args, "--no-ff");
+               argv_array_push(&cmd.args, "--no-log");
+               argv_array_push(&cmd.args, "--no-stat");
+               argv_array_push(&cmd.args, "-F");
+               argv_array_push(&cmd.args, git_path_merge_msg(the_repository));
+               if (opts->gpg_sign)
+                       argv_array_push(&cmd.args, opts->gpg_sign);
+
+               /* Add the tips to be merged */
+               for (j = to_merge; j; j = j->next)
+                       argv_array_push(&cmd.args,
+                                       oid_to_hex(&j->item->object.oid));
+
+               strbuf_release(&ref_name);
+               unlink(git_path_cherry_pick_head(the_repository));
+               rollback_lock_file(&lock);
+
+               rollback_lock_file(&lock);
+               ret = run_command(&cmd);
+
+               /* force re-reading of the cache */
+               if (!ret && (discard_cache() < 0 || read_cache() < 0))
+                       ret = error(_("could not read index"));
+               goto leave_merge;
+       }
+
+       merge_commit = to_merge->item;
        write_message(oid_to_hex(&merge_commit->object.oid), GIT_SHA1_HEXSZ,
-                     git_path_merge_head(), 0);
-       write_message("no-ff", 5, git_path_merge_mode(), 0);
+                     git_path_merge_head(the_repository), 0);
+       write_message("no-ff", 5, git_path_merge_mode(the_repository), 0);
 
        bases = get_merge_bases(head_commit, merge_commit);
        if (bases && !oidcmp(&merge_commit->object.oid,
@@ -3045,12 +3153,13 @@ static int do_merge(struct commit *commit, const char *arg, int arg_len,
                 * value (a negative one would indicate that the `merge`
                 * command needs to be rescheduled).
                 */
-               ret = !!run_git_commit(git_path_merge_msg(), opts,
+               ret = !!run_git_commit(git_path_merge_msg(the_repository), opts,
                                     run_commit_flags);
 
 leave_merge:
        strbuf_release(&ref_name);
        rollback_lock_file(&lock);
+       free_commit_list(to_merge);
        return ret;
 }
 
@@ -3228,10 +3337,27 @@ static int pick_commits(struct todo_list *todo_list, struct replay_opts *opts)
                                        intend_to_amend();
                                return error_failed_squash(item->commit, opts,
                                        item->arg_len, item->arg);
-                       } else if (res && is_rebase_i(opts) && item->commit)
+                       } else if (res && is_rebase_i(opts) && item->commit) {
+                               int to_amend = 0;
+                               struct object_id oid;
+
+                               /*
+                                * If we are rewording and have either
+                                * fast-forwarded already, or are about to
+                                * create a new root commit, we want to amend,
+                                * otherwise we do not.
+                                */
+                               if (item->command == TODO_REWORD &&
+                                   !get_oid("HEAD", &oid) &&
+                                   (!oidcmp(&item->commit->object.oid, &oid) ||
+                                    (opts->have_squash_onto &&
+                                     !oidcmp(&opts->squash_onto, &oid))))
+                                       to_amend = 1;
+
                                return res | error_with_patch(item->commit,
-                                       item->arg, item->arg_len, opts, res,
-                                       item->command == TODO_REWORD);
+                                               item->arg, item->arg_len, opts,
+                                               res, to_amend);
+                       }
                } else if (item->command == TODO_EXEC) {
                        char *end_of_arg = (char *)(item->arg + item->arg_len);
                        int saved = *end_of_arg;
@@ -3412,8 +3538,8 @@ static int continue_single_pick(void)
 {
        const char *argv[] = { "commit", NULL };
 
-       if (!file_exists(git_path_cherry_pick_head()) &&
-           !file_exists(git_path_revert_head()))
+       if (!file_exists(git_path_cherry_pick_head(the_repository)) &&
+           !file_exists(git_path_revert_head(the_repository)))
                return error(_("no cherry-pick or revert in progress"));
        return run_command_v_opt(argv, RUN_GIT_CMD);
 }
@@ -3516,7 +3642,7 @@ static int commit_staged_changes(struct replay_opts *opts,
        }
 
        if (is_clean) {
-               const char *cherry_pick_head = git_path_cherry_pick_head();
+               const char *cherry_pick_head = git_path_cherry_pick_head(the_repository);
 
                if (file_exists(cherry_pick_head) && unlink(cherry_pick_head))
                        return error(_("could not remove CHERRY_PICK_HEAD"));
@@ -3566,8 +3692,8 @@ int sequencer_continue(struct replay_opts *opts)
 
        if (!is_rebase_i(opts)) {
                /* Verify that the conflict has been resolved */
-               if (file_exists(git_path_cherry_pick_head()) ||
-                   file_exists(git_path_revert_head())) {
+               if (file_exists(git_path_cherry_pick_head(the_repository)) ||
+                   file_exists(git_path_revert_head(the_repository))) {
                        res = continue_single_pick();
                        if (res)
                                goto release_todo_list;
@@ -3619,7 +3745,7 @@ int sequencer_pick_revisions(struct replay_opts *opts)
                        continue;
 
                if (!get_oid(name, &oid)) {
-                       if (!lookup_commit_reference_gently(&oid, 1)) {
+                       if (!lookup_commit_reference_gently(the_repository, &oid, 1)) {
                                enum object_type type = oid_object_info(the_repository,
                                                                        &oid,
                                                                        NULL);
@@ -3645,8 +3771,10 @@ int sequencer_pick_revisions(struct replay_opts *opts)
                if (prepare_revision_walk(opts->revs))
                        return error(_("revision walk setup failed"));
                cmit = get_revision(opts->revs);
-               if (!cmit || get_revision(opts->revs))
-                       return error("BUG: expected exactly one commit from walk");
+               if (!cmit)
+                       return error(_("empty commit set passed"));
+               if (get_revision(opts->revs))
+                       BUG("unexpected extra commit from walk");
                return single_pick(cmit, opts);
        }
 
@@ -3888,7 +4016,6 @@ static int make_script_with_merges(struct pretty_print_context *pp,
         */
        while ((commit = get_revision(revs))) {
                struct commit_list *to_merge;
-               int is_octopus;
                const char *p1, *p2;
                struct object_id *oid;
                int is_empty;
@@ -3920,11 +4047,6 @@ static int make_script_with_merges(struct pretty_print_context *pp,
                        continue;
                }
 
-               is_octopus = to_merge && to_merge->next;
-
-               if (is_octopus)
-                       BUG("Octopus merges not yet supported");
-
                /* Create a label */
                strbuf_reset(&label);
                if (skip_prefix(oneline.buf, "Merge ", &p1) &&
@@ -3946,13 +4068,17 @@ static int make_script_with_merges(struct pretty_print_context *pp,
                strbuf_addf(&buf, "%s -C %s",
                            cmd_merge, oid_to_hex(&commit->object.oid));
 
-               /* label the tip of merged branch */
-               oid = &to_merge->item->object.oid;
-               strbuf_addch(&buf, ' ');
+               /* label the tips of merged branches */
+               for (; to_merge; to_merge = to_merge->next) {
+                       oid = &to_merge->item->object.oid;
+                       strbuf_addch(&buf, ' ');
+
+                       if (!oidset_contains(&interesting, oid)) {
+                               strbuf_addstr(&buf, label_oid(oid, NULL,
+                                                             &state));
+                               continue;
+                       }
 
-               if (!oidset_contains(&interesting, oid))
-                       strbuf_addstr(&buf, label_oid(oid, NULL, &state));
-               else {
                        tips_tail = &commit_list_insert(to_merge->item,
                                                        tips_tail)->next;
 
@@ -4005,7 +4131,7 @@ static int make_script_with_merges(struct pretty_print_context *pp,
                entry = oidmap_get(&state.commit2label, &commit->object.oid);
 
                if (entry)
-                       fprintf(out, "\n# Branch %s\n", entry->string);
+                       fprintf(out, "\n%c Branch %s\n", comment_line_char, entry->string);
                else
                        fprintf(out, "\n");
 
@@ -4143,10 +4269,9 @@ int sequencer_add_exec_commands(const char *commands)
 {
        const char *todo_file = rebase_path_todo();
        struct todo_list todo_list = TODO_LIST_INIT;
-       struct todo_item *item;
        struct strbuf *buf = &todo_list.buf;
        size_t offset = 0, commands_len = strlen(commands);
-       int i, first;
+       int i, insert;
 
        if (strbuf_read_file(&todo_list.buf, todo_file, 0) < 0)
                return error(_("could not read '%s'."), todo_file);
@@ -4156,19 +4281,40 @@ int sequencer_add_exec_commands(const char *commands)
                return error(_("unusable todo list: '%s'"), todo_file);
        }
 
-       first = 1;
-       /* insert <commands> before every pick except the first one */
-       for (item = todo_list.items, i = 0; i < todo_list.nr; i++, item++) {
-               if (item->command == TODO_PICK && !first) {
-                       strbuf_insert(buf, item->offset_in_buf + offset,
-                                     commands, commands_len);
+       /*
+        * Insert <commands> after every pick. Here, fixup/squash chains
+        * are considered part of the pick, so we insert the commands *after*
+        * those chains if there are any.
+        */
+       insert = -1;
+       for (i = 0; i < todo_list.nr; i++) {
+               enum todo_command command = todo_list.items[i].command;
+
+               if (insert >= 0) {
+                       /* skip fixup/squash chains */
+                       if (command == TODO_COMMENT)
+                               continue;
+                       else if (is_fixup(command)) {
+                               insert = i + 1;
+                               continue;
+                       }
+                       strbuf_insert(buf,
+                                     todo_list.items[insert].offset_in_buf +
+                                     offset, commands, commands_len);
                        offset += commands_len;
+                       insert = -1;
                }
-               first = 0;
+
+               if (command == TODO_PICK || command == TODO_MERGE)
+                       insert = i + 1;
        }
 
-       /* append final <commands> */
-       strbuf_add(buf, commands, commands_len);
+       /* insert or append final <commands> */
+       if (insert >= 0 && insert < todo_list.nr)
+               strbuf_insert(buf, todo_list.items[insert].offset_in_buf +
+                             offset, commands, commands_len);
+       else if (insert >= 0 || !offset)
+               strbuf_add(buf, commands, commands_len);
 
        i = write_message(buf->buf, buf->len, todo_file, 0);
        todo_list_release(&todo_list);
@@ -4252,6 +4398,7 @@ static enum check_level get_missing_commit_check_level(void)
        return CHECK_IGNORE;
 }
 
+define_commit_slab(commit_seen, unsigned char);
 /*
  * Check if the user dropped some commits by mistake
  * Behaviour determined by rebase.missingCommitsCheck.
@@ -4265,6 +4412,9 @@ int check_todo_list(void)
        struct todo_list todo_list = TODO_LIST_INIT;
        struct strbuf missing = STRBUF_INIT;
        int advise_to_edit_todo = 0, res = 0, i;
+       struct commit_seen commit_seen;
+
+       init_commit_seen(&commit_seen);
 
        strbuf_addstr(&todo_file, rebase_path_todo());
        if (strbuf_read_file_or_whine(&todo_list.buf, todo_file.buf) < 0) {
@@ -4281,7 +4431,7 @@ int check_todo_list(void)
        for (i = 0; i < todo_list.nr; i++) {
                struct commit *commit = todo_list.items[i].commit;
                if (commit)
-                       commit->util = (void *)1;
+                       *commit_seen_at(&commit_seen, commit) = 1;
        }
 
        todo_list_release(&todo_list);
@@ -4297,11 +4447,11 @@ int check_todo_list(void)
        for (i = todo_list.nr - 1; i >= 0; i--) {
                struct todo_item *item = todo_list.items + i;
                struct commit *commit = item->commit;
-               if (commit && !commit->util) {
+               if (commit && !*commit_seen_at(&commit_seen, commit)) {
                        strbuf_addf(&missing, " - %s %.*s\n",
                                    short_commit_name(commit),
                                    item->arg_len, item->arg);
-                       commit->util = (void *)1;
+                       *commit_seen_at(&commit_seen, commit) = 1;
                }
        }
 
@@ -4327,6 +4477,7 @@ int check_todo_list(void)
                "The possible behaviours are: ignore, warn, error.\n\n"));
 
 leave_check:
+       clear_commit_seen(&commit_seen);
        strbuf_release(&todo_file);
        todo_list_release(&todo_list);
 
@@ -4447,6 +4598,8 @@ static int subject2item_cmp(const void *fndata,
        return key ? strcmp(a->subject, key) : strcmp(a->subject, b->subject);
 }
 
+define_commit_slab(commit_todo_item, struct todo_item *);
+
 /*
  * Rearrange the todo list that has both "pick commit-id msg" and "pick
  * commit-id fixup!/squash! msg" in it so that the latter is put immediately
@@ -4463,6 +4616,7 @@ int rearrange_squash(void)
        struct hashmap subject2item;
        int res = 0, rearranged = 0, *next, *tail, i;
        char **subjects;
+       struct commit_todo_item commit_todo;
 
        if (strbuf_read_file_or_whine(&todo_list.buf, todo_file) < 0)
                return -1;
@@ -4471,6 +4625,7 @@ int rearrange_squash(void)
                return -1;
        }
 
+       init_commit_todo_item(&commit_todo);
        /*
         * The hashmap maps onelines to the respective todo list index.
         *
@@ -4501,10 +4656,11 @@ int rearrange_squash(void)
 
                if (is_fixup(item->command)) {
                        todo_list_release(&todo_list);
+                       clear_commit_todo_item(&commit_todo);
                        return error(_("the script was already rearranged."));
                }
 
-               item->commit->util = item;
+               *commit_todo_item_at(&commit_todo, item->commit) = item;
 
                parse_commit(item->commit);
                commit_buffer = get_commit_buffer(item->commit, NULL);
@@ -4531,9 +4687,9 @@ int rearrange_squash(void)
                        else if (!strchr(p, ' ') &&
                                 (commit2 =
                                  lookup_commit_reference_by_name(p)) &&
-                                commit2->util)
+                                *commit_todo_item_at(&commit_todo, commit2))
                                /* found by commit name */
-                               i2 = (struct todo_item *)commit2->util
+                               i2 = *commit_todo_item_at(&commit_todo, commit2)
                                        - todo_list.items;
                        else {
                                /* copy can be a prefix of the commit subject */
@@ -4610,5 +4766,6 @@ int rearrange_squash(void)
        hashmap_free(&subject2item, 1);
        todo_list_release(&todo_list);
 
+       clear_commit_todo_item(&commit_todo);
        return res;
 }