1 files changed, 586 insertions, 82 deletions

diff --git a/sequencer.c b/sequencer.c
index 4d3f60594c..667f35ebdf 100644
--- a/sequencer.c
+++ b/sequencer.c
@@ -1,10 +1,10 @@
 #include "cache.h"
 #include "config.h"
 #include "lockfile.h"
-#include "sequencer.h"
 #include "dir.h"
 #include "object.h"
 #include "commit.h"
+#include "sequencer.h"
 #include "tag.h"
 #include "run-command.h"
 #include "exec_cmd.h"
@@ -21,12 +21,16 @@
 #include "log-tree.h"
 #include "wt-status.h"
 #include "hashmap.h"
+#include "notes-utils.h"
+#include "sigchain.h"
 
 #define GIT_REFLOG_ACTION "GIT_REFLOG_ACTION"
 
 const char sign_off_header[] = "Signed-off-by: ";
 static const char cherry_picked_prefix[] = "(cherry picked from commit ";
 
+GIT_PATH_FUNC(git_path_commit_editmsg, "COMMIT_EDITMSG")
+
 GIT_PATH_FUNC(git_path_seq_dir, "sequencer")
 
 static GIT_PATH_FUNC(git_path_todo_file, "sequencer/todo")
@@ -130,6 +134,51 @@ static GIT_PATH_FUNC(rebase_path_strategy, "rebase-merge/strategy")
 static GIT_PATH_FUNC(rebase_path_strategy_opts, "rebase-merge/strategy_opts")
 static GIT_PATH_FUNC(rebase_path_allow_rerere_autoupdate, "rebase-merge/allow_rerere_autoupdate")
 
+static int git_sequencer_config(const char *k, const char *v, void *cb)
+{
+	struct replay_opts *opts = cb;
+	int status;
+
+	if (!strcmp(k, "commit.cleanup")) {
+		const char *s;
+
+		status = git_config_string(&s, k, v);
+		if (status)
+			return status;
+
+		if (!strcmp(s, "verbatim"))
+			opts->default_msg_cleanup = COMMIT_MSG_CLEANUP_NONE;
+		else if (!strcmp(s, "whitespace"))
+			opts->default_msg_cleanup = COMMIT_MSG_CLEANUP_SPACE;
+		else if (!strcmp(s, "strip"))
+			opts->default_msg_cleanup = COMMIT_MSG_CLEANUP_ALL;
+		else if (!strcmp(s, "scissors"))
+			opts->default_msg_cleanup = COMMIT_MSG_CLEANUP_SPACE;
+		else
+			warning(_("invalid commit message cleanup mode '%s'"),
+				  s);
+
+		return status;
+	}
+
+	if (!strcmp(k, "commit.gpgsign")) {
+		opts->gpg_sign = git_config_bool(k, v) ? xstrdup("") : NULL;
+		return 0;
+	}
+
+	status = git_gpg_config(k, v, NULL);
+	if (status)
+		return status;
+
+	return git_diff_basic_config(k, v, NULL);
+}
+
+void sequencer_init_config(struct replay_opts *opts)
+{
+	opts->default_msg_cleanup = COMMIT_MSG_CLEANUP_NONE;
+	git_config(git_sequencer_config, opts);
+}
+
 static inline int is_rebase_i(const struct replay_opts *opts)
 {
 	return opts->action == REPLAY_INTERACTIVE_REBASE;
@@ -233,7 +282,7 @@ struct commit_message {
 
 static const char *short_commit_name(struct commit *commit)
 {
-	return find_unique_abbrev(commit->object.oid.hash, DEFAULT_ABBREV);
+	return find_unique_abbrev(&commit->object.oid, DEFAULT_ABBREV);
 }
 
 static int get_message(struct commit *commit, struct commit_message *out)
@@ -290,7 +339,7 @@ static void print_advice(int show_hint, struct replay_opts *opts)
 static int write_message(const void *buf, size_t len, const char *filename,
 			 int append_eol)
 {
-	static struct lock_file msg_file;
+	struct lock_file msg_file = LOCK_INIT;
 
 	int msg_fd = hold_lock_file_for_update(&msg_file, filename, 0);
 	if (msg_fd < 0)
@@ -303,10 +352,8 @@ static int write_message(const void *buf, size_t len, const char *filename,
 		rollback_lock_file(&msg_file);
 		return error_errno(_("could not write eol to '%s'"), filename);
 	}
-	if (commit_lock_file(&msg_file) < 0) {
-		rollback_lock_file(&msg_file);
-		return error(_("failed to finalize '%s'."), filename);
-	}
+	if (commit_lock_file(&msg_file) < 0)
+		return error(_("failed to finalize '%s'"), filename);
 
 	return 0;
 }
@@ -436,7 +483,7 @@ static int do_recursive_merge(struct commit *base, struct commit *next,
 	struct tree *result, *next_tree, *base_tree, *head_tree;
 	int clean;
 	char **xopt;
-	static struct lock_file index_lock;
+	struct lock_file index_lock = LOCK_INIT;
 
 	if (hold_locked_index(&index_lock, LOCK_REPORT_ON_ERROR) < 0)
 		return -1;
@@ -465,21 +512,19 @@ static int do_recursive_merge(struct commit *base, struct commit *next,
 		fputs(o.obuf.buf, stdout);
 	strbuf_release(&o.obuf);
 	diff_warn_rename_limit("merge.renamelimit", o.needed_rename_limit, 0);
-	if (clean < 0)
+	if (clean < 0) {
+		rollback_lock_file(&index_lock);
 		return clean;
+	}
 
-	if (active_cache_changed &&
-	    write_locked_index(&the_index, &index_lock, COMMIT_LOCK))
+	if (write_locked_index(&the_index, &index_lock,
+			       COMMIT_LOCK | SKIP_IF_UNCHANGED))
 		/*
 		 * TRANSLATORS: %s will be "revert", "cherry-pick" or
 		 * "rebase -i".
 		 */
 		return error(_("%s: Unable to write new index file"),
 			_(action_name(opts)));
-	rollback_lock_file(&index_lock);
-
-	if (opts->signoff)
-		append_signoff(msgbuf, 0, 0);
 
 	if (!clean)
 		append_conflicts_hint(msgbuf);
@@ -596,6 +641,18 @@ static int read_env_script(struct argv_array *env)
 	return 0;
 }
 
+static char *get_author(const char *message)
+{
+	size_t len;
+	const char *a;
+
+	a = find_commit_header(message, "author", &len);
+	if (a)
+		return xmemdupz(a, len);
+
+	return NULL;
+}
+
 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"
@@ -658,8 +715,6 @@ static int run_git_commit(const char *defmsg, struct replay_opts *opts,
 		argv_array_push(&cmd.args, "--amend");
 	if (opts->gpg_sign)
 		argv_array_pushf(&cmd.args, "-S%s", opts->gpg_sign);
-	if (opts->signoff)
-		argv_array_push(&cmd.args, "-s");
 	if (defmsg)
 		argv_array_pushl(&cmd.args, "-F", defmsg, NULL);
 	if ((flags & CLEANUP_MSG))
@@ -694,6 +749,461 @@ static int run_git_commit(const char *defmsg, struct replay_opts *opts,
 	return run_command(&cmd);
 }
 
+static int rest_is_empty(const struct strbuf *sb, int start)
+{
+	int i, eol;
+	const char *nl;
+
+	/* Check if the rest is just whitespace and Signed-off-by's. */
+	for (i = start; i < sb->len; i++) {
+		nl = memchr(sb->buf + i, '\n', sb->len - i);
+		if (nl)
+			eol = nl - sb->buf;
+		else
+			eol = sb->len;
+
+		if (strlen(sign_off_header) <= eol - i &&
+		    starts_with(sb->buf + i, sign_off_header)) {
+			i = eol;
+			continue;
+		}
+		while (i < eol)
+			if (!isspace(sb->buf[i++]))
+				return 0;
+	}
+
+	return 1;
+}
+
+/*
+ * Find out if the message in the strbuf contains only whitespace and
+ * Signed-off-by lines.
+ */
+int message_is_empty(const struct strbuf *sb,
+		     enum commit_msg_cleanup_mode cleanup_mode)
+{
+	if (cleanup_mode == COMMIT_MSG_CLEANUP_NONE && sb->len)
+		return 0;
+	return rest_is_empty(sb, 0);
+}
+
+/*
+ * See if the user edited the message in the editor or left what
+ * was in the template intact
+ */
+int template_untouched(const struct strbuf *sb, const char *template_file,
+		       enum commit_msg_cleanup_mode cleanup_mode)
+{
+	struct strbuf tmpl = STRBUF_INIT;
+	const char *start;
+
+	if (cleanup_mode == COMMIT_MSG_CLEANUP_NONE && sb->len)
+		return 0;
+
+	if (!template_file || strbuf_read_file(&tmpl, template_file, 0) <= 0)
+		return 0;
+
+	strbuf_stripspace(&tmpl, cleanup_mode == COMMIT_MSG_CLEANUP_ALL);
+	if (!skip_prefix(sb->buf, tmpl.buf, &start))
+		start = sb->buf;
+	strbuf_release(&tmpl);
+	return rest_is_empty(sb, start - sb->buf);
+}
+
+int update_head_with_reflog(const struct commit *old_head,
+			    const struct object_id *new_head,
+			    const char *action, const struct strbuf *msg,
+			    struct strbuf *err)
+{
+	struct ref_transaction *transaction;
+	struct strbuf sb = STRBUF_INIT;
+	const char *nl;
+	int ret = 0;
+
+	if (action) {
+		strbuf_addstr(&sb, action);
+		strbuf_addstr(&sb, ": ");
+	}
+
+	nl = strchr(msg->buf, '\n');
+	if (nl) {
+		strbuf_add(&sb, msg->buf, nl + 1 - msg->buf);
+	} else {
+		strbuf_addbuf(&sb, msg);
+		strbuf_addch(&sb, '\n');
+	}
+
+	transaction = ref_transaction_begin(err);
+	if (!transaction ||
+	    ref_transaction_update(transaction, "HEAD", new_head,
+				   old_head ? &old_head->object.oid : &null_oid,
+				   0, sb.buf, err) ||
+	    ref_transaction_commit(transaction, err)) {
+		ret = -1;
+	}
+	ref_transaction_free(transaction);
+	strbuf_release(&sb);
+
+	return ret;
+}
+
+static int run_rewrite_hook(const struct object_id *oldoid,
+			    const struct object_id *newoid)
+{
+	struct child_process proc = CHILD_PROCESS_INIT;
+	const char *argv[3];
+	int code;
+	struct strbuf sb = STRBUF_INIT;
+
+	argv[0] = find_hook("post-rewrite");
+	if (!argv[0])
+		return 0;
+
+	argv[1] = "amend";
+	argv[2] = NULL;
+
+	proc.argv = argv;
+	proc.in = -1;
+	proc.stdout_to_stderr = 1;
+
+	code = start_command(&proc);
+	if (code)
+		return code;
+	strbuf_addf(&sb, "%s %s\n", oid_to_hex(oldoid), oid_to_hex(newoid));
+	sigchain_push(SIGPIPE, SIG_IGN);
+	write_in_full(proc.in, sb.buf, sb.len);
+	close(proc.in);
+	strbuf_release(&sb);
+	sigchain_pop(SIGPIPE);
+	return finish_command(&proc);
+}
+
+void commit_post_rewrite(const struct commit *old_head,
+			 const struct object_id *new_head)
+{
+	struct notes_rewrite_cfg *cfg;
+
+	cfg = init_copy_notes_for_rewrite("amend");
+	if (cfg) {
+		/* we are amending, so old_head is not NULL */
+		copy_note_for_rewrite(cfg, &old_head->object.oid, new_head);
+		finish_copy_notes_for_rewrite(cfg, "Notes added by 'git commit --amend'");
+	}
+	run_rewrite_hook(&old_head->object.oid, new_head);
+}
+
+static int run_prepare_commit_msg_hook(struct strbuf *msg, const char *commit)
+{
+	struct argv_array hook_env = ARGV_ARRAY_INIT;
+	int ret;
+	const char *name;
+
+	name = git_path_commit_editmsg();
+	if (write_message(msg->buf, msg->len, name, 0))
+		return -1;
+
+	argv_array_pushf(&hook_env, "GIT_INDEX_FILE=%s", get_index_file());
+	argv_array_push(&hook_env, "GIT_EDITOR=:");
+	if (commit)
+		ret = run_hook_le(hook_env.argv, "prepare-commit-msg", name,
+				  "commit", commit, NULL);
+	else
+		ret = run_hook_le(hook_env.argv, "prepare-commit-msg", name,
+				  "message", NULL);
+	if (ret)
+		ret = error(_("'prepare-commit-msg' hook failed"));
+	argv_array_clear(&hook_env);
+
+	return ret;
+}
+
+static const char implicit_ident_advice_noconfig[] =
+N_("Your name and email address were configured automatically based\n"
+"on your username and hostname. Please check that they are accurate.\n"
+"You can suppress this message by setting them explicitly. Run the\n"
+"following command and follow the instructions in your editor to edit\n"
+"your configuration file:\n"
+"\n"
+"    git config --global --edit\n"
+"\n"
+"After doing this, you may fix the identity used for this commit with:\n"
+"\n"
+"    git commit --amend --reset-author\n");
+
+static const char implicit_ident_advice_config[] =
+N_("Your name and email address were configured automatically based\n"
+"on your username and hostname. Please check that they are accurate.\n"
+"You can suppress this message by setting them explicitly:\n"
+"\n"
+"    git config --global user.name \"Your Name\"\n"
+"    git config --global user.email you@example.com\n"
+"\n"
+"After doing this, you may fix the identity used for this commit with:\n"
+"\n"
+"    git commit --amend --reset-author\n");
+
+static const char *implicit_ident_advice(void)
+{
+	char *user_config = expand_user_path("~/.gitconfig", 0);
+	char *xdg_config = xdg_config_home("config");
+	int config_exists = file_exists(user_config) || file_exists(xdg_config);
+
+	free(user_config);
+	free(xdg_config);
+
+	if (config_exists)
+		return _(implicit_ident_advice_config);
+	else
+		return _(implicit_ident_advice_noconfig);
+
+}
+
+void print_commit_summary(const char *prefix, const struct object_id *oid,
+			  unsigned int flags)
+{
+	struct rev_info rev;
+	struct commit *commit;
+	struct strbuf format = STRBUF_INIT;
+	const char *head;
+	struct pretty_print_context pctx = {0};
+	struct strbuf author_ident = STRBUF_INIT;
+	struct strbuf committer_ident = STRBUF_INIT;
+
+	commit = lookup_commit(oid);
+	if (!commit)
+		die(_("couldn't look up newly created commit"));
+	if (parse_commit(commit))
+		die(_("could not parse newly created commit"));
+
+	strbuf_addstr(&format, "format:%h] %s");
+
+	format_commit_message(commit, "%an <%ae>", &author_ident, &pctx);
+	format_commit_message(commit, "%cn <%ce>", &committer_ident, &pctx);
+	if (strbuf_cmp(&author_ident, &committer_ident)) {
+		strbuf_addstr(&format, "\n Author: ");
+		strbuf_addbuf_percentquote(&format, &author_ident);
+	}
+	if (flags & SUMMARY_SHOW_AUTHOR_DATE) {
+		struct strbuf date = STRBUF_INIT;
+
+		format_commit_message(commit, "%ad", &date, &pctx);
+		strbuf_addstr(&format, "\n Date: ");
+		strbuf_addbuf_percentquote(&format, &date);
+		strbuf_release(&date);
+	}
+	if (!committer_ident_sufficiently_given()) {
+		strbuf_addstr(&format, "\n Committer: ");
+		strbuf_addbuf_percentquote(&format, &committer_ident);
+		if (advice_implicit_identity) {
+			strbuf_addch(&format, '\n');
+			strbuf_addstr(&format, implicit_ident_advice());
+		}
+	}
+	strbuf_release(&author_ident);
+	strbuf_release(&committer_ident);
+
+	init_revisions(&rev, prefix);
+	setup_revisions(0, NULL, &rev, NULL);
+
+	rev.diff = 1;
+	rev.diffopt.output_format =
+		DIFF_FORMAT_SHORTSTAT | DIFF_FORMAT_SUMMARY;
+
+	rev.verbose_header = 1;
+	rev.show_root_diff = 1;
+	get_commit_format(format.buf, &rev);
+	rev.always_show_header = 0;
+	rev.diffopt.detect_rename = DIFF_DETECT_RENAME;
+	rev.diffopt.break_opt = 0;
+	diff_setup_done(&rev.diffopt);
+
+	head = resolve_ref_unsafe("HEAD", 0, NULL, NULL);
+	if (!head)
+		die_errno(_("unable to resolve HEAD after creating commit"));
+	if (!strcmp(head, "HEAD"))
+		head = _("detached HEAD");
+	else
+		skip_prefix(head, "refs/heads/", &head);
+	printf("[%s%s ", head, (flags & SUMMARY_INITIAL_COMMIT) ?
+						_(" (root-commit)") : "");
+
+	if (!log_tree_commit(&rev, commit)) {
+		rev.always_show_header = 1;
+		rev.use_terminator = 1;
+		log_tree_commit(&rev, commit);
+	}
+
+	strbuf_release(&format);
+}
+
+static int parse_head(struct commit **head)
+{
+	struct commit *current_head;
+	struct object_id oid;
+
+	if (get_oid("HEAD", &oid)) {
+		current_head = NULL;
+	} else {
+		current_head = lookup_commit_reference(&oid);
+		if (!current_head)
+			return error(_("could not parse HEAD"));
+		if (oidcmp(&oid, &current_head->object.oid)) {
+			warning(_("HEAD %s is not a commit!"),
+				oid_to_hex(&oid));
+		}
+		if (parse_commit(current_head))
+			return error(_("could not parse HEAD commit"));
+	}
+	*head = current_head;
+
+	return 0;
+}
+
+/*
+ * Try to commit without forking 'git commit'. In some cases we need
+ * to run 'git commit' to display an error message
+ *
+ * Returns:
+ *  -1 - error unable to commit
+ *   0 - success
+ *   1 - run 'git commit'
+ */
+static int try_to_commit(struct strbuf *msg, const char *author,
+			 struct replay_opts *opts, unsigned int flags,
+			 struct object_id *oid)
+{
+	struct object_id tree;
+	struct commit *current_head;
+	struct commit_list *parents = NULL;
+	struct commit_extra_header *extra = NULL;
+	struct strbuf err = STRBUF_INIT;
+	struct strbuf commit_msg = STRBUF_INIT;
+	char *amend_author = NULL;
+	const char *hook_commit = NULL;
+	enum commit_msg_cleanup_mode cleanup;
+	int res = 0;
+
+	if (parse_head(&current_head))
+		return -1;
+
+	if (flags & AMEND_MSG) {
+		const char *exclude_gpgsig[] = { "gpgsig", NULL };
+		const char *out_enc = get_commit_output_encoding();
+		const char *message = logmsg_reencode(current_head, NULL,
+						      out_enc);
+
+		if (!msg) {
+			const char *orig_message = NULL;
+
+			find_commit_subject(message, &orig_message);
+			msg = &commit_msg;
+			strbuf_addstr(msg, orig_message);
+			hook_commit = "HEAD";
+		}
+		author = amend_author = get_author(message);
+		unuse_commit_buffer(current_head, message);
+		if (!author) {
+			res = error(_("unable to parse commit author"));
+			goto out;
+		}
+		parents = copy_commit_list(current_head->parents);
+		extra = read_commit_extra_headers(current_head, exclude_gpgsig);
+	} else if (current_head) {
+		commit_list_insert(current_head, &parents);
+	}
+
+	if (write_cache_as_tree(&tree, 0, NULL)) {
+		res = error(_("git write-tree failed to write a tree"));
+		goto out;
+	}
+
+	if (!(flags & ALLOW_EMPTY) && !oidcmp(current_head ?
+					      &current_head->tree->object.oid :
+					      &empty_tree_oid, &tree)) {
+		res = 1; /* run 'git commit' to display error message */
+		goto out;
+	}
+
+	if (find_hook("prepare-commit-msg")) {
+		res = run_prepare_commit_msg_hook(msg, hook_commit);
+		if (res)
+			goto out;
+		if (strbuf_read_file(&commit_msg, git_path_commit_editmsg(),
+				     2048) < 0) {
+			res = error_errno(_("unable to read commit message "
+					      "from '%s'"),
+					    git_path_commit_editmsg());
+			goto out;
+		}
+		msg = &commit_msg;
+	}
+
+	cleanup = (flags & CLEANUP_MSG) ? COMMIT_MSG_CLEANUP_ALL :
+					  opts->default_msg_cleanup;
+
+	if (cleanup != COMMIT_MSG_CLEANUP_NONE)
+		strbuf_stripspace(msg, cleanup == COMMIT_MSG_CLEANUP_ALL);
+	if (!opts->allow_empty_message && message_is_empty(msg, cleanup)) {
+		res = 1; /* run 'git commit' to display error message */
+		goto out;
+	}
+
+	if (commit_tree_extended(msg->buf, msg->len, &tree, parents,
+				 oid, author, opts->gpg_sign, extra)) {
+		res = error(_("failed to write commit object"));
+		goto out;
+	}
+
+	if (update_head_with_reflog(current_head, oid,
+				    getenv("GIT_REFLOG_ACTION"), msg, &err)) {
+		res = error("%s", err.buf);
+		goto out;
+	}
+
+	if (flags & AMEND_MSG)
+		commit_post_rewrite(current_head, oid);
+
+out:
+	free_commit_extra_headers(extra);
+	strbuf_release(&err);
+	strbuf_release(&commit_msg);
+	free(amend_author);
+
+	return res;
+}
+
+static int do_commit(const char *msg_file, const char *author,
+		     struct replay_opts *opts, unsigned int flags)
+{
+	int res = 1;
+
+	if (!(flags & EDIT_MSG) && !(flags & VERIFY_MSG)) {
+		struct object_id oid;
+		struct strbuf sb = STRBUF_INIT;
+
+		if (msg_file && strbuf_read_file(&sb, msg_file, 2048) < 0)
+			return error_errno(_("unable to read commit message "
+					     "from '%s'"),
+					   msg_file);
+
+		res = try_to_commit(msg_file ? &sb : NULL, author, opts, flags,
+				    &oid);
+		strbuf_release(&sb);
+		if (!res) {
+			unlink(git_path_cherry_pick_head());
+			unlink(git_path_merge_msg());
+			if (!is_rebase_i(opts))
+				print_commit_summary(NULL, &oid,
+						SUMMARY_SHOW_AUTHOR_DATE);
+			return res;
+		}
+	}
+	if (res == 1)
+		return run_git_commit(msg_file, opts, flags);
+
+	return res;
+}
+
 static int is_original_commit_empty(struct commit *commit)
 {
 	const struct object_id *ptree_oid;
@@ -952,6 +1462,7 @@ static int do_pick_commit(enum todo_command command, struct commit *commit,
 	struct object_id head;
 	struct commit *base, *next, *parent;
 	const char *base_label, *next_label;
+	char *author = NULL;
 	struct commit_message msg = { NULL, NULL, NULL, NULL };
 	struct strbuf msgbuf = STRBUF_INIT;
 	int res, unborn = 0, allow;
@@ -963,7 +1474,7 @@ 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.hash, 0, NULL))
+		if (write_cache_as_tree(&head, 0, NULL))
 			return error(_("your index file is unmerged."));
 	} else {
 		unborn = get_oid("HEAD", &head);
@@ -1066,6 +1577,8 @@ static int do_pick_commit(enum todo_command command, struct commit *commit,
 			strbuf_addstr(&msgbuf, oid_to_hex(&commit->object.oid));
 			strbuf_addstr(&msgbuf, ")\n");
 		}
+		if (!is_fixup(command))
+			author = get_author(msg.message);
 	}
 
 	if (command == TODO_REWORD)
@@ -1091,6 +1604,9 @@ static int do_pick_commit(enum todo_command command, struct commit *commit,
 		}
 	}
 
+	if (opts->signoff)
+		append_signoff(&msgbuf, 0, 0);
+
 	if (is_rebase_i(opts) && write_author_script(msg.message) < 0)
 		res = -1;
 	else if (!opts->strategy || !strcmp(opts->strategy, "recursive") || command == TODO_REVERT) {
@@ -1148,9 +1664,13 @@ static int do_pick_commit(enum todo_command command, struct commit *commit,
 		goto leave;
 	} else if (allow)
 		flags |= ALLOW_EMPTY;
-	if (!opts->no_commit)
+	if (!opts->no_commit) {
 fast_forward_edit:
-		res = run_git_commit(msg_file, opts, flags);
+		if (author || command == TODO_REVERT || (flags & AMEND_MSG))
+			res = do_commit(msg_file, author, opts, flags);
+		else
+			res = error(_("unable to parse commit author"));
+	}
 
 	if (!res && final_fixup) {
 		unlink(rebase_path_fixup_msg());
@@ -1159,6 +1679,7 @@ fast_forward_edit:
 
 leave:
 	free_message(commit, &msg);
+	free(author);
 	update_abort_safety_file();
 
 	return res;
@@ -1183,7 +1704,7 @@ static int prepare_revs(struct replay_opts *opts)
 
 static int read_and_refresh_cache(struct replay_opts *opts)
 {
-	static struct lock_file index_lock;
+	struct lock_file index_lock = LOCK_INIT;
 	int index_fd = hold_locked_index(&index_lock, 0);
 	if (read_index_preload(&the_index, NULL) < 0) {
 		rollback_lock_file(&index_lock);
@@ -1191,13 +1712,13 @@ static int read_and_refresh_cache(struct replay_opts *opts)
 			_(action_name(opts)));
 	}
 	refresh_index(&the_index, REFRESH_QUIET|REFRESH_UNMERGED, NULL, NULL, NULL);
-	if (the_index.cache_changed && index_fd >= 0) {
-		if (write_locked_index(&the_index, &index_lock, COMMIT_LOCK)) {
+	if (index_fd >= 0) {
+		if (write_locked_index(&the_index, &index_lock,
+				       COMMIT_LOCK | SKIP_IF_UNCHANGED)) {
 			return error(_("git %s: failed to refresh the index"),
 				_(action_name(opts)));
 		}
 	}
-	rollback_lock_file(&index_lock);
 	return 0;
 }
 
@@ -1347,22 +1868,31 @@ static int count_commands(struct todo_list *todo_list)
 	return count;
 }
 
+static ssize_t strbuf_read_file_or_whine(struct strbuf *sb, const char *path)
+{
+	int fd;
+	ssize_t len;
+
+	fd = open(path, O_RDONLY);
+	if (fd < 0)
+		return error_errno(_("could not open '%s'"), path);
+	len = strbuf_read(sb, fd, 0);
+	close(fd);
+	if (len < 0)
+		return error(_("could not read '%s'."), path);
+	return len;
+}
+
 static int read_populate_todo(struct todo_list *todo_list,
 			struct replay_opts *opts)
 {
 	struct stat st;
 	const char *todo_file = get_todo_path(opts);
-	int fd, res;
+	int res;
 
 	strbuf_reset(&todo_list->buf);
-	fd = open(todo_file, O_RDONLY);
-	if (fd < 0)
-		return error_errno(_("could not open '%s'"), todo_file);
-	if (strbuf_read(&todo_list->buf, fd, 0) < 0) {
-		close(fd);
-		return error(_("could not read '%s'."), todo_file);
-	}
-	close(fd);
+	if (strbuf_read_file_or_whine(&todo_list->buf, todo_file) < 0)
+		return -1;
 
 	res = stat(todo_file, &st);
 	if (res)
@@ -1577,16 +2107,14 @@ static int create_seq_dir(void)
 
 static int save_head(const char *head)
 {
-	static struct lock_file head_lock;
+	struct lock_file head_lock = LOCK_INIT;
 	struct strbuf buf = STRBUF_INIT;
 	int fd;
 	ssize_t written;
 
 	fd = hold_lock_file_for_update(&head_lock, git_path_head_file(), 0);
-	if (fd < 0) {
-		rollback_lock_file(&head_lock);
+	if (fd < 0)
 		return error_errno(_("could not lock HEAD"));
-	}
 	strbuf_addf(&buf, "%s\n", head);
 	written = write_in_full(fd, buf.buf, buf.len);
 	strbuf_release(&buf);
@@ -1595,10 +2123,8 @@ static int save_head(const char *head)
 		return error_errno(_("could not write to '%s'"),
 				   git_path_head_file());
 	}
-	if (commit_lock_file(&head_lock) < 0) {
-		rollback_lock_file(&head_lock);
-		return error(_("failed to finalize '%s'."), git_path_head_file());
-	}
+	if (commit_lock_file(&head_lock) < 0)
+		return error(_("failed to finalize '%s'"), git_path_head_file());
 	return 0;
 }
 
@@ -1702,7 +2228,7 @@ fail:
 
 static int save_todo(struct todo_list *todo_list, struct replay_opts *opts)
 {
-	static struct lock_file todo_lock;
+	struct lock_file todo_lock = LOCK_INIT;
 	const char *todo_path = get_todo_path(opts);
 	int next = todo_list->current, offset, fd;
 
@@ -1722,7 +2248,7 @@ static int save_todo(struct todo_list *todo_list, struct replay_opts *opts)
 			todo_list->buf.len - offset) < 0)
 		return error_errno(_("could not write to '%s'"), todo_path);
 	if (commit_lock_file(&todo_lock) < 0)
-		return error(_("failed to finalize '%s'."), todo_path);
+		return error(_("failed to finalize '%s'"), todo_path);
 
 	if (is_rebase_i(opts)) {
 		const char *done_path = rebase_path_done();
@@ -1792,6 +2318,9 @@ static int make_patch(struct commit *commit, struct replay_opts *opts)
 	p = short_commit_name(commit);
 	if (write_message(p, strlen(p), rebase_path_stopped_sha(), 1) < 0)
 		return -1;
+	if (update_ref("rebase", "REBASE_HEAD", &commit->object.oid,
+		       NULL, REF_NO_DEREF, UPDATE_REFS_MSG_ON_ERR))
+		res |= error(_("could not update %s"), "REBASE_HEAD");
 
 	strbuf_addf(&buf, "%s/patch", get_dir(opts));
 	memset(&log_tree_opt, 0, sizeof(log_tree_opt));
@@ -2043,6 +2572,7 @@ static int pick_commits(struct todo_list *todo_list, struct replay_opts *opts)
 			unlink(rebase_path_author_script());
 			unlink(rebase_path_stopped_sha());
 			unlink(rebase_path_amend());
+			delete_ref(NULL, "REBASE_HEAD", NULL, REF_NO_DEREF);
 		}
 		if (item->command <= TODO_SQUASH) {
 			if (is_rebase_i(opts))
@@ -2346,9 +2876,10 @@ int sequencer_pick_revisions(struct replay_opts *opts)
 
 		if (!get_oid(name, &oid)) {
 			if (!lookup_commit_reference_gently(&oid, 1)) {
-				enum object_type type = sha1_object_info(oid.hash, NULL);
+				enum object_type type = oid_object_info(&oid,
+									NULL);
 				return error(_("%s: can't cherry-pick a %s"),
-					name, typename(type));
+					name, type_name(type));
 			}
 		} else
 			return error(_("%s: bad revision"), name);
@@ -2629,20 +3160,13 @@ int check_todo_list(void)
 	struct strbuf todo_file = STRBUF_INIT;
 	struct todo_list todo_list = TODO_LIST_INIT;
 	struct strbuf missing = STRBUF_INIT;
-	int advise_to_edit_todo = 0, res = 0, fd, i;
+	int advise_to_edit_todo = 0, res = 0, i;
 
 	strbuf_addstr(&todo_file, rebase_path_todo());
-	fd = open(todo_file.buf, O_RDONLY);
-	if (fd < 0) {
-		res = error_errno(_("could not open '%s'"), todo_file.buf);
-		goto leave_check;
-	}
-	if (strbuf_read(&todo_list.buf, fd, 0) < 0) {
-		close(fd);
-		res = error(_("could not read '%s'."), todo_file.buf);
+	if (strbuf_read_file_or_whine(&todo_list.buf, todo_file.buf) < 0) {
+		res = -1;
 		goto leave_check;
 	}
-	close(fd);
 	advise_to_edit_todo = res =
 		parse_insn_buffer(todo_list.buf.buf, &todo_list);
 
@@ -2658,17 +3182,10 @@ int check_todo_list(void)
 
 	todo_list_release(&todo_list);
 	strbuf_addstr(&todo_file, ".backup");
-	fd = open(todo_file.buf, O_RDONLY);
-	if (fd < 0) {
-		res = error_errno(_("could not open '%s'"), todo_file.buf);
-		goto leave_check;
-	}
-	if (strbuf_read(&todo_list.buf, fd, 0) < 0) {
-		close(fd);
-		res = error(_("could not read '%s'."), todo_file.buf);
+	if (strbuf_read_file_or_whine(&todo_list.buf, todo_file.buf) < 0) {
+		res = -1;
 		goto leave_check;
 	}
-	close(fd);
 	strbuf_release(&todo_file);
 	res = !!parse_insn_buffer(todo_list.buf.buf, &todo_list);
 
@@ -2749,15 +3266,8 @@ int skip_unnecessary_picks(void)
 	}
 	strbuf_release(&buf);
 
-	fd = open(todo_file, O_RDONLY);
-	if (fd < 0) {
-		return error_errno(_("could not open '%s'"), todo_file);
-	}
-	if (strbuf_read(&todo_list.buf, fd, 0) < 0) {
-		close(fd);
-		return error(_("could not read '%s'."), todo_file);
-	}
-	close(fd);
+	if (strbuf_read_file_or_whine(&todo_list.buf, todo_file) < 0)
+		return -1;
 	if (parse_insn_buffer(todo_list.buf.buf, &todo_list) < 0) {
 		todo_list_release(&todo_list);
 		return -1;
@@ -2848,17 +3358,11 @@ int rearrange_squash(void)
 	const char *todo_file = rebase_path_todo();
 	struct todo_list todo_list = TODO_LIST_INIT;
 	struct hashmap subject2item;
-	int res = 0, rearranged = 0, *next, *tail, fd, i;
+	int res = 0, rearranged = 0, *next, *tail, i;
 	char **subjects;
 
-	fd = open(todo_file, O_RDONLY);
-	if (fd < 0)
-		return error_errno(_("could not open '%s'"), todo_file);
-	if (strbuf_read(&todo_list.buf, fd, 0) < 0) {
-		close(fd);
-		return error(_("could not read '%s'."), todo_file);
-	}
-	close(fd);
+	if (strbuf_read_file_or_whine(&todo_list.buf, todo_file) < 0)
+		return -1;
 	if (parse_insn_buffer(todo_list.buf.buf, &todo_list) < 0) {
 		todo_list_release(&todo_list);
 		return -1;