1 files changed, 675 insertions, 108 deletions

diff --git a/sequencer.c b/sequencer.c
index c31d48b..a35a0e6 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;
@@ -347,7 +396,7 @@ static int read_oneliner(struct strbuf *buf,
 
 static struct tree *empty_tree(void)
 {
-	return lookup_tree(&empty_tree_oid);
+	return lookup_tree(the_hash_algo->empty_tree);
 }
 
 static int error_dirty_index(struct replay_opts *opts)
@@ -393,7 +442,7 @@ static int fast_forward_to(const struct object_id *to, const struct object_id *f
 	transaction = ref_transaction_begin(&err);
 	if (!transaction ||
 	    ref_transaction_update(transaction, "HEAD",
-				   to->hash, unborn ? null_sha1 : from->hash,
+				   to, unborn ? &null_oid : from,
 				   0, sb.buf, &err) ||
 	    ref_transaction_commit(transaction, &err)) {
 		ref_transaction_free(transaction);
@@ -438,7 +487,8 @@ static int do_recursive_merge(struct commit *base, struct commit *next,
 	char **xopt;
 	static struct lock_file index_lock;
 
-	hold_locked_index(&index_lock, LOCK_DIE_ON_ERROR);
+	if (hold_locked_index(&index_lock, LOCK_REPORT_ON_ERROR) < 0)
+		return -1;
 
 	read_cache();
 
@@ -448,6 +498,7 @@ static int do_recursive_merge(struct commit *base, struct commit *next,
 	o.branch2 = next ? next_label : "(empty tree)";
 	if (is_rebase_i(opts))
 		o.buffer_output = 2;
+	o.show_rename_progress = 1;
 
 	head_tree = parse_tree_indirect(head);
 	next_tree = next ? next->tree : empty_tree();
@@ -462,6 +513,7 @@ static int do_recursive_merge(struct commit *base, struct commit *next,
 	if (is_rebase_i(opts) && clean <= 0)
 		fputs(o.obuf.buf, stdout);
 	strbuf_release(&o.obuf);
+	diff_warn_rename_limit("merge.renamelimit", o.needed_rename_limit, 0);
 	if (clean < 0)
 		return clean;
 
@@ -475,9 +527,6 @@ static int do_recursive_merge(struct commit *base, struct commit *next,
 			_(action_name(opts)));
 	rollback_lock_file(&index_lock);
 
-	if (opts->signoff)
-		append_signoff(msgbuf, 0, 0);
-
 	if (!clean)
 		append_conflicts_hint(msgbuf);
 
@@ -489,8 +538,8 @@ static int is_index_unchanged(void)
 	struct object_id head_oid;
 	struct commit *head_commit;
 
-	if (!resolve_ref_unsafe("HEAD", RESOLVE_REF_READING, head_oid.hash, NULL))
-		return error(_("could not resolve HEAD commit\n"));
+	if (!resolve_ref_unsafe("HEAD", RESOLVE_REF_READING, &head_oid, NULL))
+		return error(_("could not resolve HEAD commit"));
 
 	head_commit = lookup_commit(&head_oid);
 
@@ -510,7 +559,7 @@ static int is_index_unchanged(void)
 
 	if (!cache_tree_fully_valid(active_cache_tree))
 		if (cache_tree_update(&the_index, 0))
-			return error(_("unable to update cache tree\n"));
+			return error(_("unable to update cache tree"));
 
 	return !oidcmp(&active_cache_tree->oid,
 		       &head_commit->tree->object.oid);
@@ -593,6 +642,18 @@ 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"
@@ -655,8 +716,6 @@ 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))
@@ -691,21 +750,476 @@ 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.hash, 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;
 
 	if (parse_commit(commit))
-		return error(_("could not parse commit %s\n"),
+		return error(_("could not parse commit %s"),
 			     oid_to_hex(&commit->object.oid));
 	if (commit->parents) {
 		struct commit *parent = commit->parents->item;
 		if (parse_commit(parent))
-			return error(_("could not parse parent commit %s\n"),
+			return error(_("could not parse parent commit %s"),
 				oid_to_hex(&parent->object.oid));
 		ptree_oid = &parent->tree->object.oid;
 	} else {
-		ptree_oid = &empty_tree_oid; /* commit is root */
+		ptree_oid = the_hash_algo->empty_tree; /* commit is root */
 	}
 
 	return !oidcmp(ptree_oid, &commit->tree->object.oid);
@@ -794,6 +1308,13 @@ static const char *command_to_string(const enum todo_command command)
 	die("Unknown command: %d", command);
 }
 
+static char command_to_char(const enum todo_command command)
+{
+	if (command < TODO_COMMENT && todo_command_info[command].c)
+		return todo_command_info[command].c;
+	return comment_line_char;
+}
+
 static int is_noop(const enum todo_command command)
 {
 	return TODO_NOOP <= command;
@@ -942,6 +1463,7 @@ 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;
@@ -958,8 +1480,9 @@ static int do_pick_commit(enum todo_command command, struct commit *commit,
 	} else {
 		unborn = get_oid("HEAD", &head);
 		if (unborn)
-			oidcpy(&head, &empty_tree_oid);
-		if (index_differs_from(unborn ? EMPTY_TREE_SHA1_HEX : "HEAD", 0, 0))
+			oidcpy(&head, the_hash_algo->empty_tree);
+		if (index_differs_from(unborn ? EMPTY_TREE_SHA1_HEX : "HEAD",
+				       NULL, 0))
 			return error_dirty_index(opts);
 	}
 	discard_cache();
@@ -1002,9 +1525,7 @@ static int do_pick_commit(enum todo_command command, struct commit *commit,
 			opts);
 		if (res || command != TODO_REWORD)
 			goto leave;
-		flags |= EDIT_MSG | AMEND_MSG;
-		if (command == TODO_REWORD)
-			flags |= VERIFY_MSG;
+		flags |= EDIT_MSG | AMEND_MSG | VERIFY_MSG;
 		msg_file = NULL;
 		goto fast_forward_edit;
 	}
@@ -1057,6 +1578,8 @@ 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)
@@ -1082,6 +1605,9 @@ 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) {
@@ -1115,12 +1641,12 @@ static int do_pick_commit(enum todo_command command, struct commit *commit,
 	 * write it at all.
 	 */
 	if (command == TODO_PICK && !opts->no_commit && (res == 0 || res == 1) &&
-	    update_ref(NULL, "CHERRY_PICK_HEAD", commit->object.oid.hash, NULL,
-		       REF_NODEREF, UPDATE_REFS_MSG_ON_ERR))
+	    update_ref(NULL, "CHERRY_PICK_HEAD", &commit->object.oid, NULL,
+		       REF_NO_DEREF, UPDATE_REFS_MSG_ON_ERR))
 		res = -1;
 	if (command == TODO_REVERT && ((opts->no_commit && res == 0) || res == 1) &&
-	    update_ref(NULL, "REVERT_HEAD", commit->object.oid.hash, NULL,
-		       REF_NODEREF, UPDATE_REFS_MSG_ON_ERR))
+	    update_ref(NULL, "REVERT_HEAD", &commit->object.oid, NULL,
+		       REF_NO_DEREF, UPDATE_REFS_MSG_ON_ERR))
 		res = -1;
 
 	if (res) {
@@ -1139,9 +1665,13 @@ 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());
@@ -1150,6 +1680,7 @@ fast_forward_edit:
 
 leave:
 	free_message(commit, &msg);
+	free(author);
 	update_abort_safety_file();
 
 	return res;
@@ -1184,7 +1715,6 @@ static int read_and_refresh_cache(struct replay_opts *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)) {
-			rollback_lock_file(&index_lock);
 			return error(_("git %s: failed to refresh the index"),
 				_(action_name(opts)));
 		}
@@ -1253,20 +1783,26 @@ static int parse_insn_line(struct todo_item *item, const char *bol, char *eol)
 	if (i >= TODO_COMMENT)
 		return -1;
 
+	/* Eat up extra spaces/ tabs before object name */
+	padding = strspn(bol, " \t");
+	bol += padding;
+
 	if (item->command == TODO_NOOP) {
+		if (bol != eol)
+			return error(_("%s does not accept arguments: '%s'"),
+				     command_to_string(item->command), bol);
 		item->commit = NULL;
 		item->arg = bol;
 		item->arg_len = eol - bol;
 		return 0;
 	}
 
-	/* Eat up extra spaces/ tabs before object name */
-	padding = strspn(bol, " \t");
 	if (!padding)
-		return -1;
-	bol += padding;
+		return error(_("missing arguments for %s"),
+			     command_to_string(item->command));
 
 	if (item->command == TODO_EXEC) {
+		item->commit = NULL;
 		item->arg = bol;
 		item->arg_len = (int)(eol - bol);
 		return 0;
@@ -1639,7 +2175,7 @@ static int rollback_single_pick(void)
 	if (!file_exists(git_path_cherry_pick_head()) &&
 	    !file_exists(git_path_revert_head()))
 		return error(_("no cherry-pick or revert in progress"));
-	if (read_ref_full("HEAD", 0, head_oid.hash, NULL))
+	if (read_ref_full("HEAD", 0, &head_oid, NULL))
 		return error(_("cannot resolve HEAD"));
 	if (is_null_oid(&head_oid))
 		return error(_("cannot abort from a branch yet to be born"));
@@ -1787,6 +2323,9 @@ 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));
@@ -1871,12 +2410,15 @@ static int error_failed_squash(struct commit *commit,
 
 static int do_exec(const char *command_line)
 {
+	struct argv_array child_env = ARGV_ARRAY_INIT;
 	const char *child_argv[] = { NULL, NULL };
 	int dirty, status;
 
 	fprintf(stderr, "Executing: %s\n", command_line);
 	child_argv[0] = command_line;
-	status = run_command_v_opt(child_argv, RUN_USING_SHELL);
+	argv_array_pushf(&child_env, "GIT_DIR=%s", absolute_path(get_git_dir()));
+	status = run_command_v_opt_cd_env(child_argv, RUN_USING_SHELL, NULL,
+					  child_env.argv);
 
 	/* force re-reading of the cache */
 	if (discard_cache() < 0 || read_cache() < 0)
@@ -1906,6 +2448,8 @@ static int do_exec(const char *command_line)
 		status = 1;
 	}
 
+	argv_array_clear(&child_env);
+
 	return status;
 }
 
@@ -2033,6 +2577,7 @@ 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))
@@ -2133,8 +2678,8 @@ cleanup_head_ref:
 			}
 			msg = reflog_message(opts, "finish", "%s onto %s",
 				head_ref.buf, buf.buf);
-			if (update_ref(msg, head_ref.buf, head.hash, orig.hash,
-					REF_NODEREF, UPDATE_REFS_MSG_ON_ERR)) {
+			if (update_ref(msg, head_ref.buf, &head, &orig,
+				       REF_NO_DEREF, UPDATE_REFS_MSG_ON_ERR)) {
 				res = error(_("could not update %s"),
 					head_ref.buf);
 				goto cleanup_head_ref;
@@ -2288,7 +2833,7 @@ int sequencer_continue(struct replay_opts *opts)
 			if (res)
 				goto release_todo_list;
 		}
-		if (index_differs_from("HEAD", 0, 0)) {
+		if (index_differs_from("HEAD", NULL, 0)) {
 			res = error_dirty_index(opts);
 			goto release_todo_list;
 		}
@@ -2446,14 +2991,16 @@ void append_signoff(struct strbuf *msgbuf, int ignore_footer, unsigned flag)
 	strbuf_release(&sob);
 }
 
-int sequencer_make_script(int keep_empty, FILE *out,
-		int argc, const char **argv)
+int sequencer_make_script(FILE *out, int argc, const char **argv,
+			  unsigned flags)
 {
 	char *format = NULL;
 	struct pretty_print_context pp = {0};
 	struct strbuf buf = STRBUF_INIT;
 	struct rev_info revs;
 	struct commit *commit;
+	int keep_empty = flags & TODO_LIST_KEEP_EMPTY;
+	const char *insn = flags & TODO_LIST_ABBREVIATE_CMDS ? "p" : "pick";
 
 	init_revisions(&revs, NULL);
 	revs.verbose_header = 1;
@@ -2486,7 +3033,8 @@ int sequencer_make_script(int keep_empty, FILE *out,
 		strbuf_reset(&buf);
 		if (!keep_empty && is_original_commit_empty(commit))
 			strbuf_addf(&buf, "%c ", comment_line_char);
-		strbuf_addf(&buf, "pick %s ", oid_to_hex(&commit->object.oid));
+		strbuf_addf(&buf, "%s %s ", insn,
+			    oid_to_hex(&commit->object.oid));
 		pretty_print_commit(&pp, commit, &buf);
 		strbuf_addch(&buf, '\n');
 		fputs(buf.buf, out);
@@ -2495,61 +3043,93 @@ int sequencer_make_script(int keep_empty, FILE *out,
 	return 0;
 }
 
-
-int transform_todo_ids(int shorten_ids)
+/*
+ * Add commands after pick and (series of) squash/fixup commands
+ * in the todo list.
+ */
+int sequencer_add_exec_commands(const char *commands)
 {
 	const char *todo_file = rebase_path_todo();
 	struct todo_list todo_list = TODO_LIST_INIT;
-	int fd, res, i;
-	FILE *out;
+	struct todo_item *item;
+	struct strbuf *buf = &todo_list.buf;
+	size_t offset = 0, commands_len = strlen(commands);
+	int i, first;
 
-	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);
+	if (strbuf_read_file(&todo_list.buf, todo_file, 0) < 0)
 		return error(_("could not read '%s'."), todo_file);
-	}
-	close(fd);
 
-	res = parse_insn_buffer(todo_list.buf.buf, &todo_list);
-	if (res) {
+	if (parse_insn_buffer(todo_list.buf.buf, &todo_list)) {
 		todo_list_release(&todo_list);
 		return error(_("unusable todo list: '%s'"), todo_file);
 	}
 
-	out = fopen(todo_file, "w");
-	if (!out) {
+	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);
+			offset += commands_len;
+		}
+		first = 0;
+	}
+
+	/* append final <commands> */
+	strbuf_add(buf, commands, commands_len);
+
+	i = write_message(buf->buf, buf->len, todo_file, 0);
+	todo_list_release(&todo_list);
+	return i;
+}
+
+int transform_todos(unsigned flags)
+{
+	const char *todo_file = rebase_path_todo();
+	struct todo_list todo_list = TODO_LIST_INIT;
+	struct strbuf buf = STRBUF_INIT;
+	struct todo_item *item;
+	int i;
+
+	if (strbuf_read_file(&todo_list.buf, todo_file, 0) < 0)
+		return error(_("could not read '%s'."), todo_file);
+
+	if (parse_insn_buffer(todo_list.buf.buf, &todo_list)) {
 		todo_list_release(&todo_list);
-		return error(_("unable to open '%s' for writing"), todo_file);
+		return error(_("unusable todo list: '%s'"), todo_file);
 	}
-	for (i = 0; i < todo_list.nr; i++) {
-		struct todo_item *item = todo_list.items + i;
-		int bol = item->offset_in_buf;
-		const char *p = todo_list.buf.buf + bol;
-		int eol = i + 1 < todo_list.nr ?
-			todo_list.items[i + 1].offset_in_buf :
-			todo_list.buf.len;
-
-		if (item->command >= TODO_EXEC && item->command != TODO_DROP)
-			fwrite(p, eol - bol, 1, out);
-		else {
-			const char *id = shorten_ids ?
-				short_commit_name(item->commit) :
-				oid_to_hex(&item->commit->object.oid);
-			int len;
-
-			p += strspn(p, " \t"); /* left-trim command */
-			len = strcspn(p, " \t"); /* length of command */
-
-			fprintf(out, "%.*s %s %.*s\n",
-				len, p, id, item->arg_len, item->arg);
+
+	for (item = todo_list.items, i = 0; i < todo_list.nr; i++, item++) {
+		/* if the item is not a command write it and continue */
+		if (item->command >= TODO_COMMENT) {
+			strbuf_addf(&buf, "%.*s\n", item->arg_len, item->arg);
+			continue;
+		}
+
+		/* add command to the buffer */
+		if (flags & TODO_LIST_ABBREVIATE_CMDS)
+			strbuf_addch(&buf, command_to_char(item->command));
+		else
+			strbuf_addstr(&buf, command_to_string(item->command));
+
+		/* add commit id */
+		if (item->commit) {
+			const char *oid = flags & TODO_LIST_SHORTEN_IDS ?
+					  short_commit_name(item->commit) :
+					  oid_to_hex(&item->commit->object.oid);
+
+			strbuf_addf(&buf, " %s", oid);
 		}
+		/* add all the rest */
+		if (!item->arg_len)
+			strbuf_addch(&buf, '\n');
+		else
+			strbuf_addf(&buf, " %.*s\n", item->arg_len, item->arg);
 	}
-	fclose(out);
+
+	i = write_message(buf.buf, buf.len, todo_file, 0);
 	todo_list_release(&todo_list);
-	return 0;
+	return i;
 }
 
 enum check_level {
@@ -2660,6 +3240,19 @@ leave_check:
 	return res;
 }
 
+static int rewrite_file(const char *path, const char *buf, size_t len)
+{
+	int rc = 0;
+	int fd = open(path, O_WRONLY | O_TRUNC);
+	if (fd < 0)
+		return error_errno(_("could not open '%s' for writing"), path);
+	if (write_in_full(fd, buf, len) < 0)
+		rc = error_errno(_("could not write to '%s'"), path);
+	if (close(fd) && !rc)
+		rc = error_errno(_("could not close '%s'"), path);
+	return rc;
+}
+
 /* skip picking commits whose parents are unchanged */
 int skip_unnecessary_picks(void)
 {
@@ -2725,29 +3318,11 @@ int skip_unnecessary_picks(void)
 		}
 		close(fd);
 
-		fd = open(rebase_path_todo(), O_WRONLY, 0666);
-		if (fd < 0) {
-			error_errno(_("could not open '%s' for writing"),
-				    rebase_path_todo());
-			todo_list_release(&todo_list);
-			return -1;
-		}
-		if (write_in_full(fd, todo_list.buf.buf + offset,
-				todo_list.buf.len - offset) < 0) {
-			error_errno(_("could not write to '%s'"),
-				    rebase_path_todo());
-			close(fd);
-			todo_list_release(&todo_list);
-			return -1;
-		}
-		if (ftruncate(fd, todo_list.buf.len - offset) < 0) {
-			error_errno(_("could not truncate '%s'"),
-				    rebase_path_todo());
+		if (rewrite_file(rebase_path_todo(), todo_list.buf.buf + offset,
+				 todo_list.buf.len - offset) < 0) {
 			todo_list_release(&todo_list);
-			close(fd);
 			return -1;
 		}
-		close(fd);
 
 		todo_list.current = i;
 		if (is_fixup(peek_command(&todo_list, 0)))
@@ -2926,15 +3501,7 @@ int rearrange_squash(void)
 			}
 		}
 
-		fd = open(todo_file, O_WRONLY);
-		if (fd < 0)
-			res = error_errno(_("could not open '%s'"), todo_file);
-		else if (write(fd, buf.buf, buf.len) < 0)
-			res = error_errno(_("could not write to '%s'"), todo_file);
-		else if (ftruncate(fd, buf.len) < 0)
-			res = error_errno(_("could not truncate '%s'"),
-					   todo_file);
-		close(fd);
+		res = rewrite_file(todo_file, buf.buf, buf.len);
 		strbuf_release(&buf);
 	}