Merge 'prepare-sequencer' into HEAD

builtin/commit.c

@@ -173,7 +173,7 @@ static void determine_whence(struct wt_status *s)
 		whence = FROM_MERGE;
 	else if (file_exists(git_path_cherry_pick_head())) {
 		whence = FROM_CHERRY_PICK;
-		if (file_exists(git_path(SEQ_DIR)))
+		if (file_exists(git_path_seq_dir()))
 			sequencer_in_use = 1;
 	}
 	else

builtin/revert.c

@@ -71,7 +71,7 @@ static void verify_opt_compatible(const char *me, const char *base_opt, ...)
 		die(_("%s: %s cannot be used with %s"), me, this_opt, base_opt);
 }
 
-static void parse_args(int argc, const char **argv, struct replay_opts *opts)
+static int run_sequencer(int argc, const char **argv, struct replay_opts *opts)
 {
 	const char * const * usage_str = revert_or_cherry_pick_usage(opts);
 	const char *me = action_name(opts);
@@ -115,25 +115,15 @@ static void parse_args(int argc, const char **argv, struct replay_opts *opts)
 	if (opts->keep_redundant_commits)
 		opts->allow_empty = 1;
 
-	/* Set the subcommand */
-	if (cmd == 'q')
-		opts->subcommand = REPLAY_REMOVE_STATE;
-	else if (cmd == 'c')
-		opts->subcommand = REPLAY_CONTINUE;
-	else if (cmd == 'a')
-		opts->subcommand = REPLAY_ROLLBACK;
-	else
-		opts->subcommand = REPLAY_NONE;
-
 	/* Check for incompatible command line arguments */
-	if (opts->subcommand != REPLAY_NONE) {
+	if (cmd) {
 		char *this_operation;
-		if (opts->subcommand == REPLAY_REMOVE_STATE)
+		if (cmd == 'q')
 			this_operation = "--quit";
-		else if (opts->subcommand == REPLAY_CONTINUE)
+		else if (cmd == 'c')
 			this_operation = "--continue";
 		else {
-			assert(opts->subcommand == REPLAY_ROLLBACK);
+			assert(cmd == 'a');
 			this_operation = "--abort";
 		}
 
@@ -156,7 +146,7 @@ static void parse_args(int argc, const char **argv, struct replay_opts *opts)
 				"--edit", opts->edit,
 				NULL);
 
-	if (opts->subcommand != REPLAY_NONE) {
+	if (cmd) {
 		opts->revs = NULL;
 	} else {
 		struct setup_revision_opt s_r_opt;
@@ -174,20 +164,26 @@ static void parse_args(int argc, const char **argv, struct replay_opts *opts)
 
 	if (argc > 1)
 		usage_with_options(usage_str, options);
+
+	if (cmd == 'q')
+		return sequencer_remove_state(opts);
+	if (cmd == 'c')
+		return sequencer_continue(opts);
+	if (cmd == 'a')
+		return sequencer_rollback(opts);
+	return sequencer_pick_revisions(opts);
 }
 
 int cmd_revert(int argc, const char **argv, const char *prefix)
 {
-	struct replay_opts opts;
+	struct replay_opts opts = REPLAY_OPTS_INIT;
 	int res;
 
-	memset(&opts, 0, sizeof(opts));
 	if (isatty(0))
 		opts.edit = 1;
 	opts.action = REPLAY_REVERT;
 	git_config(git_default_config, NULL);
-	parse_args(argc, argv, &opts);
-	res = sequencer_pick_revisions(&opts);
+	res = run_sequencer(argc, argv, &opts);
 	if (res < 0)
 		die(_("revert failed"));
 	return res;
@@ -195,14 +191,12 @@ int cmd_revert(int argc, const char **argv, const char *prefix)
 
 int cmd_cherry_pick(int argc, const char **argv, const char *prefix)
 {
-	struct replay_opts opts;
+	struct replay_opts opts = REPLAY_OPTS_INIT;
 	int res;
 
-	memset(&opts, 0, sizeof(opts));
 	opts.action = REPLAY_PICK;
 	git_config(git_default_config, NULL);
-	parse_args(argc, argv, &opts);
-	res = sequencer_pick_revisions(&opts);
+	res = run_sequencer(argc, argv, &opts);
 	if (res < 0)
 		die(_("cherry-pick failed"));
 	return res;

sequencer.c

@@ -15,16 +15,46 @@
 #include "merge-recursive.h"
 #include "refs.h"
 #include "argv-array.h"
+#include "quote.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 ";
 
-static GIT_PATH_FUNC(git_path_todo_file, SEQ_TODO_FILE)
-static GIT_PATH_FUNC(git_path_opts_file, SEQ_OPTS_FILE)
-static GIT_PATH_FUNC(git_path_seq_dir, SEQ_DIR)
-static GIT_PATH_FUNC(git_path_head_file, SEQ_HEAD_FILE)
+GIT_PATH_FUNC(git_path_seq_dir, "sequencer")
+
+static GIT_PATH_FUNC(git_path_todo_file, "sequencer/todo")
+static GIT_PATH_FUNC(git_path_opts_file, "sequencer/opts")
+static GIT_PATH_FUNC(git_path_head_file, "sequencer/head")
+
+/*
+ * A script to set the GIT_AUTHOR_NAME, GIT_AUTHOR_EMAIL, and
+ * GIT_AUTHOR_DATE that will be used for the commit that is currently
+ * being rebased.
+ */
+static GIT_PATH_FUNC(rebase_path_author_script, "rebase-merge/author-script")
+/*
+ * The following files are written by git-rebase just after parsing the
+ * command-line (and are only consumed, not modified, by the sequencer).
+ */
+static GIT_PATH_FUNC(rebase_path_gpg_sign_opt, "rebase-merge/gpg_sign_opt")
+
+/* We will introduce the 'interactive rebase' mode later */
+static inline int is_rebase_i(const struct replay_opts *opts)
+{
+	return 0;
+}
+
+static const char *get_dir(const struct replay_opts *opts)
+{
+	return git_path_seq_dir();
+}
+
+static const char *get_todo_path(const struct replay_opts *opts)
+{
+	return git_path_todo_file();
+}
 
 static int is_rfc2822_line(const char *buf, int len)
 {
@@ -108,18 +138,45 @@ static int has_conforming_footer(struct strbuf *sb, struct strbuf *sob,
 	return 1;
 }
 
-static void remove_sequencer_state(void)
+static const char *gpg_sign_opt_quoted(struct replay_opts *opts)
 {
-	struct strbuf seq_dir = STRBUF_INIT;
+	static struct strbuf buf = STRBUF_INIT;
 
-	strbuf_addstr(&seq_dir, git_path(SEQ_DIR));
-	remove_dir_recursively(&seq_dir, 0);
-	strbuf_release(&seq_dir);
+	strbuf_reset(&buf);
+	if (opts->gpg_sign)
+		sq_quotef(&buf, "-S%s", opts->gpg_sign);
+	return buf.buf;
+}
+
+void *sequencer_entrust(struct replay_opts *opts, void *to_free)
+{
+	ALLOC_GROW(opts->owned, opts->owned_nr + 1, opts->owned_alloc);
+	opts->owned[opts->owned_nr++] = to_free;
+
+	return to_free;
+}
+
+int sequencer_remove_state(struct replay_opts *opts)
+{
+	struct strbuf dir = STRBUF_INIT;
+	int i;
+
+	for (i = 0; i < opts->owned_nr; i++)
+		free(opts->owned[i]);
+	free(opts->owned);
+
+	free(opts->xopts);
+
+	strbuf_addf(&dir, "%s", get_dir(opts));
+	remove_dir_recursively(&dir, 0);
+	strbuf_release(&dir);
+
+	return 0;
 }
 
 static const char *action_name(const struct replay_opts *opts)
 {
-	return opts->action == REPLAY_REVERT ? "revert" : "cherry-pick";
+	return opts->action == REPLAY_REVERT ? N_("revert") : N_("cherry-pick");
 }
 
 struct commit_message {
@@ -129,13 +186,18 @@ struct commit_message {
 	const char *message;
 };
 
+static const char *short_commit_name(struct commit *commit)
+{
+	return find_unique_abbrev(commit->object.oid.hash, DEFAULT_ABBREV);
+}
+
 static int get_message(struct commit *commit, struct commit_message *out)
 {
 	const char *abbrev, *subject;
 	int subject_len;
 
 	out->message = logmsg_reencode(commit, NULL, get_commit_output_encoding());
-	abbrev = find_unique_abbrev(commit->object.oid.hash, DEFAULT_ABBREV);
+	abbrev = short_commit_name(commit);
 
 	subject_len = find_commit_subject(out->message, &subject);
 
@@ -180,22 +242,68 @@ static void print_advice(int show_hint, struct replay_opts *opts)
 	}
 }
 
-static int write_message(struct strbuf *msgbuf, const char *filename)
+static int write_with_lock_file(const char *filename,
+				const void *buf, size_t len, int append_eol)
 {
 	static struct lock_file msg_file;
 
 	int msg_fd = hold_lock_file_for_update(&msg_file, filename, 0);
 	if (msg_fd < 0)
 		return error_errno(_("Could not lock '%s'"), filename);
-	if (write_in_full(msg_fd, msgbuf->buf, msgbuf->len) < 0)
-		return error_errno(_("Could not write to %s"), filename);
-	strbuf_release(msgbuf);
+	if (write_in_full(msg_fd, buf, len) < 0)
+		return error_errno(_("Could not write to '%s'"), filename);
+	if (append_eol && write(msg_fd, "\n", 1) < 0)
+		return error_errno(_("Could not write eol to '%s"), filename);
 	if (commit_lock_file(&msg_file) < 0)
-		return error(_("Error wrapping up %s."), filename);
+		return error(_("Error wrapping up '%s'."), filename);
 
 	return 0;
 }
 
+static int write_message(struct strbuf *msgbuf, const char *filename)
+{
+	int res = write_with_lock_file(filename, msgbuf->buf, msgbuf->len, 0);
+	strbuf_release(msgbuf);
+	return res;
+}
+
+static int write_file_gently(const char *filename,
+			     const char *text, int append_eol)
+{
+	return write_with_lock_file(filename, text, strlen(text), append_eol);
+}
+
+/*
+ * Reads a file that was presumably written by a shell script, i.e.
+ * with an end-of-line marker that needs to be stripped.
+ *
+ * Returns 1 if the file was read, 0 if it could not be read or does not exist.
+ */
+static int read_oneliner(struct strbuf *buf,
+	const char *path, int skip_if_empty)
+{
+	int orig_len = buf->len;
+
+	if (!file_exists(path))
+		return 0;
+
+	if (strbuf_read_file(buf, path, 0) < 0) {
+		warning_errno("could not read '%s'", path);
+		return 0;
+	}
+
+	if (buf->len > orig_len && buf->buf[buf->len - 1] == '\n') {
+		if (--buf->len > orig_len && buf->buf[buf->len - 1] == '\r')
+			--buf->len;
+		buf->buf[buf->len] = '\0';
+	}
+
+	if (skip_if_empty && buf->len == orig_len)
+		return 0;
+
+	return 1;
+}
+
 static struct tree *empty_tree(void)
 {
 	return lookup_tree(EMPTY_TREE_SHA1_BIN);
@@ -204,13 +312,10 @@ static struct tree *empty_tree(void)
 static int error_dirty_index(struct replay_opts *opts)
 {
 	if (read_cache_unmerged())
-		return error_resolve_conflict(action_name(opts));
+		return error_resolve_conflict(_(action_name(opts)));
 
-	/* Different translation strings for cherry-pick and revert */
-	if (opts->action == REPLAY_PICK)
-		error(_("Your local changes would be overwritten by cherry-pick."));
-	else
-		error(_("Your local changes would be overwritten by revert."));
+	error(_("Your local changes would be overwritten by %s."),
+		_(action_name(opts)));
 
 	if (advice_commit_before_merge)
 		advise(_("Commit your changes or stash them to proceed."));
@@ -228,7 +333,7 @@ static int fast_forward_to(const unsigned char *to, const unsigned char *from,
 	if (checkout_fast_forward(from, to, 1))
 		return -1; /* the callee should have complained already */
 
-	strbuf_addf(&sb, _("%s: fast-forward"), action_name(opts));
+	strbuf_addf(&sb, _("%s: fast-forward"), _(action_name(opts)));
 
 	transaction = ref_transaction_begin(&err);
 	if (!transaction ||
@@ -304,7 +409,7 @@ static int do_recursive_merge(struct commit *base, struct commit *next,
 	    write_locked_index(&the_index, &index_lock, COMMIT_LOCK))
 		/* TRANSLATORS: %s will be "revert" or "cherry-pick" */
 		return error(_("%s: Unable to write new index file"),
-			action_name(opts));
+			_(action_name(opts)));
 	rollback_lock_file(&index_lock);
 
 	if (opts->signoff)
@@ -347,36 +452,100 @@ static int is_index_unchanged(void)
 	return !hashcmp(active_cache_tree->sha1, head_commit->tree->object.oid.hash);
 }
 
+static char **read_author_script(void)
+{
+	struct strbuf script = STRBUF_INIT;
+	int i, count = 0;
+	char *p, *p2, **env;
+	size_t env_size;
+
+	if (strbuf_read_file(&script, rebase_path_author_script(), 256) <= 0)
+		return NULL;
+
+	for (p = script.buf; *p; p++)
+		if (skip_prefix(p, "'\\\\''", (const char **)&p2))
+			strbuf_splice(&script, p - script.buf, p2 - p, "'", 1);
+		else if (*p == '\'')
+			strbuf_splice(&script, p-- - script.buf, 1, "", 0);
+		else if (*p == '\n') {
+			*p = '\0';
+			count++;
+		}
+
+	env_size = (count + 1) * sizeof(*env);
+	strbuf_grow(&script, env_size);
+	memmove(script.buf + env_size, script.buf, script.len);
+	p = script.buf + env_size;
+	env = (char **)strbuf_detach(&script, NULL);
+
+	for (i = 0; i < count; i++) {
+		env[i] = p;
+		p += strlen(p) + 1;
+	}
+	env[count] = NULL;
+
+	return env;
+}
+
 /*
  * If we are cherry-pick, and if the merge did not result in
  * hand-editing, we will hit this commit and inherit the original
  * author date and name.
+ *
  * If we are revert, or if our cherry-pick results in a hand merge,
  * we had better say that the current user is responsible for that.
+ *
+ * An exception is when sequencer_commit() is called during an
+ * interactive rebase: in that case, we will want to retain the
+ * author metadata.
  */
-static int run_git_commit(const char *defmsg, struct replay_opts *opts,
-			  int allow_empty)
+int sequencer_commit(const char *defmsg, struct replay_opts *opts,
+			  int allow_empty, int edit, int amend,
+			  int cleanup_commit_message)
 {
+	char **env = NULL;
 	struct argv_array array;
 	int rc;
 	const char *value;
 
+	if (is_rebase_i(opts)) {
+		env = read_author_script();
+		if (!env) {
+			const char *gpg_opt = gpg_sign_opt_quoted(opts);
+
+			return error("You have staged changes in your working "
+				"tree. If these changes are meant to be\n"
+				"squashed into the previous commit, run:\n\n"
+				"  git commit --amend %s\n\n"
+				"If they are meant to go into a new commit, "
+				"run:\n\n"
+				"  git commit %s\n\n"
+				"In both cases, once you're done, continue "
+				"with:\n\n"
+				"  git rebase --continue\n", gpg_opt, gpg_opt);
+		}
+	}
+
 	argv_array_init(&array);
 	argv_array_push(&array, "commit");
 	argv_array_push(&array, "-n");
 
+	if (amend)
+		argv_array_push(&array, "--amend");
 	if (opts->gpg_sign)
 		argv_array_pushf(&array, "-S%s", opts->gpg_sign);
 	if (opts->signoff)
 		argv_array_push(&array, "-s");
-	if (!opts->edit) {
-		argv_array_push(&array, "-F");
-		argv_array_push(&array, defmsg);
-		if (!opts->signoff &&
-		    !opts->record_origin &&
-		    git_config_get_value("commit.cleanup", &value))
-			argv_array_push(&array, "--cleanup=verbatim");
-	}
+	if (defmsg)
+		argv_array_pushl(&array, "-F", defmsg, NULL);
+	if (cleanup_commit_message)
+		argv_array_push(&array, "--cleanup=strip");
+	if (edit)
+		argv_array_push(&array, "-e");
+	else if (!cleanup_commit_message &&
+		 !opts->signoff && !opts->record_origin &&
+		 git_config_get_value("commit.cleanup", &value))
+		argv_array_push(&array, "--cleanup=verbatim");
 
 	if (allow_empty)
 		argv_array_push(&array, "--allow-empty");
@@ -384,8 +553,11 @@ static int run_git_commit(const char *defmsg, struct replay_opts *opts,
 	if (opts->allow_empty_message)
 		argv_array_push(&array, "--allow-empty-message");
 
-	rc = run_command_v_opt(array.argv, RUN_GIT_CMD);
+	rc = run_command_v_opt_cd_env(array.argv, RUN_GIT_CMD, NULL,
+			(const char *const *)env);
 	argv_array_clear(&array);
+	free(env);
+
 	return rc;
 }
 
@@ -447,14 +619,33 @@ static int allow_empty(struct replay_opts *opts, struct commit *commit)
 		return 1;
 }
 
-static int do_pick_commit(struct commit *commit, struct replay_opts *opts)
+enum todo_command {
+	TODO_PICK = 0,
+	TODO_REVERT
+};
+
+static const char *todo_command_strings[] = {
+	"pick",
+	"revert"
+};
+
+static const char *command_to_string(const enum todo_command command)
+{
+	if (command < ARRAY_SIZE(todo_command_strings))
+		return todo_command_strings[command];
+	die("Unknown command: %d", command);
+}
+
+
+static int do_pick_commit(enum todo_command command, struct commit *commit,
+		struct replay_opts *opts)
 {
 	unsigned char head[20];
 	struct commit *base, *next, *parent;
 	const char *base_label, *next_label;
 	struct commit_message msg = { NULL, NULL, NULL, NULL };
 	struct strbuf msgbuf = STRBUF_INIT;
-	int res, unborn = 0, allow;
+	int res = 0, unborn = 0, allow;
 
 	if (opts->no_commit) {
 		/*
@@ -506,10 +697,9 @@ static int do_pick_commit(struct commit *commit, struct replay_opts *opts)
 		return fast_forward_to(commit->object.oid.hash, head, unborn, opts);
 
 	if (parent && parse_commit(parent) < 0)
-		/* TRANSLATORS: The first %s will be "revert" or
-		   "cherry-pick", the second %s a SHA1 */
 		return error(_("%s: cannot parse parent commit %s"),
-			action_name(opts), oid_to_hex(&parent->object.oid));
+			command_to_string(command),
+			oid_to_hex(&parent->object.oid));
 
 	if (get_message(commit, &msg) != 0)
 		return error(_("Cannot get commit message for %s"),
@@ -522,7 +712,7 @@ static int do_pick_commit(struct commit *commit, struct replay_opts *opts)
 	 * reverse of it if we are revert.
 	 */
 
-	if (opts->action == REPLAY_REVERT) {
+	if (command == TODO_REVERT) {
 		base = commit;
 		base_label = msg.label;
 		next = parent;
@@ -563,8 +753,8 @@ static int do_pick_commit(struct commit *commit, struct replay_opts *opts)
 		}
 	}
 
-	if (!opts->strategy || !strcmp(opts->strategy, "recursive") || opts->action == REPLAY_REVERT) {
-		res = do_recursive_merge(base, next, base_label, next_label,
+	if (!opts->strategy || !strcmp(opts->strategy, "recursive") || command == TODO_REVERT) {
+		res |= do_recursive_merge(base, next, base_label, next_label,
 					 head, &msgbuf, opts);
 		if (res < 0)
 			return res;
@@ -573,7 +763,7 @@ static int do_pick_commit(struct commit *commit, struct replay_opts *opts)
 		struct commit_list *common = NULL;
 		struct commit_list *remotes = NULL;
 
-		res = write_message(&msgbuf, git_path_merge_msg());
+		res |= write_message(&msgbuf, git_path_merge_msg());
 
 		commit_list_insert(base, &common);
 		commit_list_insert(next, &remotes);
@@ -589,21 +779,20 @@ static int do_pick_commit(struct commit *commit, struct replay_opts *opts)
 	 * However, if the merge did not even start, then we don't want to
 	 * write it at all.
 	 */
-	if (opts->action == REPLAY_PICK && !opts->no_commit && (res == 0 || res == 1) &&
+	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))
 		res = -1;
-	if (opts->action == REPLAY_REVERT && ((opts->no_commit && res == 0) || 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))
 		res = -1;
 
 	if (res) {
-		error(opts->action == REPLAY_REVERT
+		error(command == TODO_REVERT
 		      ? _("could not revert %s... %s")
 		      : _("could not apply %s... %s"),
-		      find_unique_abbrev(commit->object.oid.hash, DEFAULT_ABBREV),
-		      msg.subject);
+		      short_commit_name(commit), msg.subject);
 		print_advice(res == 1, opts);
 		rerere(opts->allow_rerere_auto);
 		goto leave;
@@ -611,11 +800,13 @@ static int do_pick_commit(struct commit *commit, struct replay_opts *opts)
 
 	allow = allow_empty(opts, commit);
 	if (allow < 0) {
-		res = allow;
+		res |= allow;
 		goto leave;
 	}
 	if (!opts->no_commit)
-		res = run_git_commit(git_path_merge_msg(), opts, allow);
+		res |= sequencer_commit(opts->edit ?
+				NULL : git_path_merge_msg(),
+			opts, allow, opts->edit, 0, 0);
 
 leave:
 	free_message(commit, &msg);
@@ -647,133 +838,146 @@ static int read_and_refresh_cache(struct replay_opts *opts)
 	if (read_index_preload(&the_index, NULL) < 0) {
 		rollback_lock_file(&index_lock);
 		return error(_("git %s: failed to read the index"),
-			action_name(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)) {
 			rollback_lock_file(&index_lock);
 			return error(_("git %s: failed to refresh the index"),
-				action_name(opts));
+				_(action_name(opts)));
 		}
 	}
 	rollback_lock_file(&index_lock);
 	return 0;
 }
 
-static int format_todo(struct strbuf *buf, struct commit_list *todo_list,
-		struct replay_opts *opts)
-{
-	struct commit_list *cur = NULL;
-	const char *sha1_abbrev = NULL;
-	const char *action_str = opts->action == REPLAY_REVERT ? "revert" : "pick";
-	const char *subject;
-	int subject_len;
+struct todo_item {
+	enum todo_command command;
+	struct commit *commit;
+	const char *arg;
+	int arg_len;
+	size_t offset_in_buf;
+};
 
-	for (cur = todo_list; cur; cur = cur->next) {
-		const char *commit_buffer = get_commit_buffer(cur->item, NULL);
-		sha1_abbrev = find_unique_abbrev(cur->item->object.oid.hash, DEFAULT_ABBREV);
-		subject_len = find_commit_subject(commit_buffer, &subject);
-		strbuf_addf(buf, "%s %s %.*s\n", action_str, sha1_abbrev,
-			subject_len, subject);
-		unuse_commit_buffer(cur->item, commit_buffer);
-	}
-	return 0;
+struct todo_list {
+	struct strbuf buf;
+	struct todo_item *items;
+	int nr, alloc, current;
+};
+
+#define TODO_LIST_INIT { STRBUF_INIT }
+
+static void todo_list_release(struct todo_list *todo_list)
+{
+	strbuf_release(&todo_list->buf);
+	free(todo_list->items);
+	todo_list->items = NULL;
+	todo_list->nr = todo_list->alloc = 0;
 }
 
-static struct commit *parse_insn_line(char *bol, char *eol, struct replay_opts *opts)
+struct todo_item *append_new_todo(struct todo_list *todo_list)
+{
+	ALLOC_GROW(todo_list->items, todo_list->nr + 1, todo_list->alloc);
+	return todo_list->items + todo_list->nr++;
+}
+
+static int parse_insn_line(struct todo_item *item, const char *bol, char *eol)
 {
 	unsigned char commit_sha1[20];
-	enum replay_action action;
 	char *end_of_object_name;
-	int saved, status, padding;
+	int i, saved, status, padding;
 
-	if (starts_with(bol, "pick")) {
-		action = REPLAY_PICK;
-		bol += strlen("pick");
-	} else if (starts_with(bol, "revert")) {
-		action = REPLAY_REVERT;
-		bol += strlen("revert");
-	} else
-		return NULL;
+	/* left-trim */
+	bol += strspn(bol, " \t");
+
+	for (i = 0; i < ARRAY_SIZE(todo_command_strings); i++)
+		if (skip_prefix(bol, todo_command_strings[i], &bol)) {
+			item->command = i;
+			break;
+		}
+	if (i >= ARRAY_SIZE(todo_command_strings))
+		return -1;
 
 	/* Eat up extra spaces/ tabs before object name */
 	padding = strspn(bol, " \t");
 	if (!padding)
-		return NULL;
+		return -1;
 	bol += padding;
 
-	end_of_object_name = bol + strcspn(bol, " \t\n");
+	end_of_object_name = (char *) bol + strcspn(bol, " \t\n");
 	saved = *end_of_object_name;
 	*end_of_object_name = '\0';
 	status = get_sha1(bol, commit_sha1);
 	*end_of_object_name = saved;
 
-	/*
-	 * Verify that the action matches up with the one in
-	 * opts; we don't support arbitrary instructions
-	 */
-	if (action != opts->action) {
-		if (action == REPLAY_REVERT)
-		      error((opts->action == REPLAY_REVERT)
-			    ? _("Cannot revert during another revert.")
-			    : _("Cannot revert during a cherry-pick."));
-		else
-		      error((opts->action == REPLAY_REVERT)
-			    ? _("Cannot cherry-pick during a revert.")
-			    : _("Cannot cherry-pick during another cherry-pick."));
-		return NULL;
-	}
+	item->arg = end_of_object_name + strspn(end_of_object_name, " \t");
+	item->arg_len = (int)(eol - item->arg);
 
 	if (status < 0)
-		return NULL;
+		return -1;
 
-	return lookup_commit_reference(commit_sha1);
+	item->commit = lookup_commit_reference(commit_sha1);
+	return !item->commit;
 }
 
-static int parse_insn_buffer(char *buf, struct commit_list **todo_list,
-			struct replay_opts *opts)
+static int parse_insn_buffer(char *buf, struct todo_list *todo_list)
 {
-	struct commit_list **next = todo_list;
-	struct commit *commit;
+	struct todo_item *item;
 	char *p = buf;
-	int i;
+	int i, res = 0;
 
 	for (i = 1; *p; i++) {
 		char *eol = strchrnul(p, '\n');
-		commit = parse_insn_line(p, eol, opts);
-		if (!commit)
-			return error(_("Could not parse line %d."), i);
-		next = commit_list_append(commit, next);
+
+		item = append_new_todo(todo_list);
+		item->offset_in_buf = p - todo_list->buf.buf;
+		if (parse_insn_line(item, p, eol)) {
+			res |= error(_("Invalid line %d: %.*s"),
+				i, (int)(eol - p), p);
+			item->command = -1;
+		}
 		p = *eol ? eol + 1 : eol;
 	}
-	if (!*todo_list)
+	if (!todo_list->nr)
 		return error(_("No commits parsed."));
-	return 0;
+	return res;
 }
 
-static int read_populate_todo(struct commit_list **todo_list,
+static int read_populate_todo(struct todo_list *todo_list,
 			struct replay_opts *opts)
 {
-	struct strbuf buf = STRBUF_INIT;
+	const char *todo_file = get_todo_path(opts);
 	int fd, res;
 
-	fd = open(git_path_todo_file(), O_RDONLY);
+	strbuf_reset(&todo_list->buf);
+	fd = open(todo_file, O_RDONLY);
 	if (fd < 0)
-		return error_errno(_("Could not open %s"),
-				   git_path_todo_file());
-	if (strbuf_read(&buf, fd, 0) < 0) {
+		return error_errno(_("Could not open '%s'"), todo_file);
+	if (strbuf_read(&todo_list->buf, fd, 0) < 0) {
 		close(fd);
-		strbuf_release(&buf);
-		return error(_("Could not read %s."), git_path_todo_file());
+		return error(_("Could not read '%s'."), todo_file);
 	}
 	close(fd);
 
-	res = parse_insn_buffer(buf.buf, todo_list, opts);
-	strbuf_release(&buf);
+	res = parse_insn_buffer(todo_list->buf.buf, todo_list);
 	if (res)
-		return error(_("Unusable instruction sheet: %s"),
-			git_path_todo_file());
+		return error(_("Unusable instruction sheet: '%s'"), todo_file);
+
+	if (!is_rebase_i(opts)) {
+		enum todo_command valid =
+			opts->action == REPLAY_PICK ? TODO_PICK : TODO_REVERT;
+		int i;
+
+		for (i = 0; i < todo_list->nr; i++)
+			if (valid == todo_list->items[i].command)
+				continue;
+			else if (valid == TODO_PICK)
+				return error(_("Cannot cherry-pick during a revert."));
+			else
+				return error(_("Cannot revert during a cherry-pick."));
+	}
+
 	return 0;
 }
 
@@ -796,13 +1000,18 @@ static int populate_opts_cb(const char *key, const char *value, void *data)
 		opts->allow_ff = git_config_bool_or_int(key, value, &error_flag);
 	else if (!strcmp(key, "options.mainline"))
 		opts->mainline = git_config_int(key, value);
-	else if (!strcmp(key, "options.strategy"))
+	else if (!strcmp(key, "options.strategy")) {
 		git_config_string(&opts->strategy, key, value);
-	else if (!strcmp(key, "options.gpg-sign"))
+		sequencer_entrust(opts, (char *) opts->strategy);
+	}
+	else if (!strcmp(key, "options.gpg-sign")) {
 		git_config_string(&opts->gpg_sign, key, value);
+		sequencer_entrust(opts, (char *) opts->gpg_sign);
+	}
 	else if (!strcmp(key, "options.strategy-option")) {
 		ALLOC_GROW(opts->xopts, opts->xopts_nr + 1, opts->xopts_alloc);
-		opts->xopts[opts->xopts_nr++] = xstrdup(value);
+		opts->xopts[opts->xopts_nr++] =
+			sequencer_entrust(opts, xstrdup(value));
 	} else
 		return error(_("Invalid key: %s"), key);
 
@@ -812,8 +1021,24 @@ static int populate_opts_cb(const char *key, const char *value, void *data)
 	return 0;
 }
 
-static int read_populate_opts(struct replay_opts **opts)
+static int read_populate_opts(struct replay_opts *opts)
 {
+	if (is_rebase_i(opts)) {
+		struct strbuf buf = STRBUF_INIT;
+
+		if (read_oneliner(&buf, rebase_path_gpg_sign_opt(), 1)) {
+			if (!starts_with(buf.buf, "-S"))
+				strbuf_reset(&buf);
+			else {
+				opts->gpg_sign = buf.buf + 2;
+				sequencer_entrust(opts,
+					strbuf_detach(&buf, NULL));
+			}
+		}
+
+		return 0;
+	}
+
 	if (!file_exists(git_path_opts_file()))
 		return 0;
 	/*
@@ -822,24 +1047,39 @@ static int read_populate_opts(struct replay_opts **opts)
 	 * about this case, though, because we wrote that file ourselves, so we
 	 * are pretty certain that it is syntactically correct.
 	 */
-	if (git_config_from_file(populate_opts_cb, git_path_opts_file(), *opts) < 0)
-		return error(_("Malformed options sheet: %s"),
+	if (git_config_from_file(populate_opts_cb, git_path_opts_file(), opts) < 0)
+		return error(_("Malformed options sheet: '%s'"),
 			git_path_opts_file());
 	return 0;
 }
 
-static int walk_revs_populate_todo(struct commit_list **todo_list,
+static int walk_revs_populate_todo(struct todo_list *todo_list,
 				struct replay_opts *opts)
 {
+	enum todo_command command = opts->action == REPLAY_PICK ?
+		TODO_PICK : TODO_REVERT;
+	const char *command_string = todo_command_strings[command];
 	struct commit *commit;
-	struct commit_list **next;
 
 	if (prepare_revs(opts))
 		return -1;
 
-	next = todo_list;
-	while ((commit = get_revision(opts->revs)))
-		next = commit_list_append(commit, next);
+	while ((commit = get_revision(opts->revs))) {
+		struct todo_item *item = append_new_todo(todo_list);
+		const char *commit_buffer = get_commit_buffer(commit, NULL);
+		const char *subject;
+		int subject_len;
+
+		item->command = command;
+		item->commit = commit;
+		item->arg = NULL;
+		item->arg_len = 0;
+		item->offset_in_buf = todo_list->buf.len;
+		subject_len = find_commit_subject(commit_buffer, &subject);
+		strbuf_addf(&todo_list->buf, "%s %s %.*s\n", command_string,
+			short_commit_name(commit), subject_len, subject);
+		unuse_commit_buffer(commit, commit_buffer);
+	}
 	return 0;
 }
 
@@ -851,7 +1091,7 @@ static int create_seq_dir(void)
 		return -1;
 	}
 	else if (mkdir(git_path_seq_dir(), 0777) < 0)
-		return error_errno(_("Could not create sequencer directory %s"),
+		return error_errno(_("Could not create sequencer directory '%s'"),
 				   git_path_seq_dir());
 	return 0;
 }
@@ -870,12 +1110,12 @@ static int save_head(const char *head)
 	strbuf_addf(&buf, "%s\n", head);
 	if (write_in_full(fd, buf.buf, buf.len) < 0) {
 		rollback_lock_file(&head_lock);
-		return error_errno(_("Could not write to %s"),
+		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(_("Error wrapping up %s."), git_path_head_file());
+		return error(_("Error wrapping up '%s'."), git_path_head_file());
 	}
 	return 0;
 }
@@ -904,7 +1144,7 @@ static int rollback_single_pick(void)
 	return reset_for_rollback(head_sha1);
 }
 
-static int sequencer_rollback(struct replay_opts *opts)
+int sequencer_rollback(struct replay_opts *opts)
 {
 	FILE *f;
 	unsigned char sha1[20];
@@ -920,9 +1160,9 @@ static int sequencer_rollback(struct replay_opts *opts)
 		return rollback_single_pick();
 	}
 	if (!f)
-		return error_errno(_("cannot open %s"), git_path_head_file());
+		return error_errno(_("cannot open '%s'"), git_path_head_file());
 	if (strbuf_getline_lf(&buf, f)) {
-		error(_("cannot read %s: %s"), git_path_head_file(),
+		error(_("cannot read '%s': %s"), git_path_head_file(),
 		      ferror(f) ?  strerror(errno) : _("unexpected end of file"));
 		fclose(f);
 		goto fail;
@@ -939,38 +1179,29 @@ static int sequencer_rollback(struct replay_opts *opts)
 	}
 	if (reset_for_rollback(sha1))
 		goto fail;
-	remove_sequencer_state();
 	strbuf_release(&buf);
-	return 0;
+	return sequencer_remove_state(opts);
 fail:
 	strbuf_release(&buf);
 	return -1;
 }
 
-static int save_todo(struct commit_list *todo_list, struct replay_opts *opts)
+static int save_todo(struct todo_list *todo_list, struct replay_opts *opts)
 {
 	static struct lock_file todo_lock;
-	struct strbuf buf = STRBUF_INIT;
-	int fd;
+	const char *todo_path = get_todo_path(opts);
+	int next = todo_list->current, offset, fd;
 
-	fd = hold_lock_file_for_update(&todo_lock, git_path_todo_file(), 0);
+	fd = hold_lock_file_for_update(&todo_lock, todo_path, 0);
 	if (fd < 0)
-		return error_errno(_("Could not lock '%s'"),
-				   git_path_todo_file());
-	if (format_todo(&buf, todo_list, opts) < 0) {
-		strbuf_release(&buf);
-		return error(_("Could not format %s."), git_path_todo_file());
-	}
-	if (write_in_full(fd, buf.buf, buf.len) < 0) {
-		strbuf_release(&buf);
-		return error_errno(_("Could not write to %s"),
-				   git_path_todo_file());
-	}
-	if (commit_lock_file(&todo_lock) < 0) {
-		strbuf_release(&buf);
-		return error(_("Error wrapping up %s."), git_path_todo_file());
-	}
-	strbuf_release(&buf);
+		return error_errno(_("Could not lock '%s'"), todo_path);
+	offset = next < todo_list->nr ?
+		todo_list->items[next].offset_in_buf : todo_list->buf.len;
+	if (write_in_full(fd, todo_list->buf.buf + offset,
+			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(_("Error wrapping up '%s'."), todo_path);
 	return 0;
 }
 
@@ -1009,9 +1240,8 @@ static int save_opts(struct replay_opts *opts)
 	return res;
 }
 
-static int pick_commits(struct commit_list *todo_list, struct replay_opts *opts)
+static int pick_commits(struct todo_list *todo_list, struct replay_opts *opts)
 {
-	struct commit_list *cur;
 	int res;
 
 	setenv(GIT_REFLOG_ACTION, action_name(opts), 0);
@@ -1021,10 +1251,12 @@ static int pick_commits(struct commit_list *todo_list, struct replay_opts *opts)
 	if (read_and_refresh_cache(opts))
 		return -1;
 
-	for (cur = todo_list; cur; cur = cur->next) {
-		if (save_todo(cur, opts))
+	while (todo_list->current < todo_list->nr) {
+		struct todo_item *item = todo_list->items + todo_list->current;
+		if (save_todo(todo_list, opts))
 			return -1;
-		res = do_pick_commit(cur->item, opts);
+		res = do_pick_commit(item->command, item->commit, opts);
+		todo_list->current++;
 		if (res)
 			return res;
 	}
@@ -1033,8 +1265,7 @@ static int pick_commits(struct commit_list *todo_list, struct replay_opts *opts)
 	 * Sequence of picks finished successfully; cleanup by
 	 * removing the .git/sequencer directory
 	 */
-	remove_sequencer_state();
-	return 0;
+	return sequencer_remove_state(opts);
 }
 
 static int continue_single_pick(void)
@@ -1047,61 +1278,56 @@ static int continue_single_pick(void)
 	return run_command_v_opt(argv, RUN_GIT_CMD);
 }
 
-static int sequencer_continue(struct replay_opts *opts)
+int sequencer_continue(struct replay_opts *opts)
 {
-	struct commit_list *todo_list = NULL;
+	struct todo_list todo_list = TODO_LIST_INIT;
+	int res;
 
-	if (!file_exists(git_path_todo_file()))
-		return continue_single_pick();
-	if (read_populate_opts(&opts) ||
-			read_populate_todo(&todo_list, opts))
+	if (read_and_refresh_cache(opts))
 		return -1;
 
+	if (!file_exists(get_todo_path(opts)))
+		return continue_single_pick();
+	if (read_populate_opts(opts))
+		return -1;
+	if ((res = read_populate_todo(&todo_list, opts)))
+		goto release_todo_list;
+
 	/* Verify that the conflict has been resolved */
 	if (file_exists(git_path_cherry_pick_head()) ||
 	    file_exists(git_path_revert_head())) {
-		int ret = continue_single_pick();
-		if (ret)
-			return ret;
+		res = continue_single_pick();
+		if (res)
+			goto release_todo_list;
 	}
-	if (index_differs_from("HEAD", 0))
-		return error_dirty_index(opts);
-	todo_list = todo_list->next;
-	return pick_commits(todo_list, opts);
+	if (index_differs_from("HEAD", 0)) {
+		res = error_dirty_index(opts);
+		goto release_todo_list;
+	}
+	todo_list.current++;
+	res = pick_commits(&todo_list, opts);
+release_todo_list:
+	todo_list_release(&todo_list);
+	return res;
 }
 
 static int single_pick(struct commit *cmit, struct replay_opts *opts)
 {
 	setenv(GIT_REFLOG_ACTION, action_name(opts), 0);
-	return do_pick_commit(cmit, opts);
+	return do_pick_commit(opts->action == REPLAY_PICK ?
+		TODO_PICK : TODO_REVERT, cmit, opts);
 }
 
 int sequencer_pick_revisions(struct replay_opts *opts)
 {
-	struct commit_list *todo_list = NULL;
+	struct todo_list todo_list = TODO_LIST_INIT;
 	unsigned char sha1[20];
-	int i;
-
-	if (opts->subcommand == REPLAY_NONE)
-		assert(opts->revs);
+	int i, res;
 
+	assert(opts->revs);
 	if (read_and_refresh_cache(opts))
 		return -1;
 
-	/*
-	 * Decide what to do depending on the arguments; a fresh
-	 * cherry-pick should be handled differently from an existing
-	 * one that is being continued
-	 */
-	if (opts->subcommand == REPLAY_REMOVE_STATE) {
-		remove_sequencer_state();
-		return 0;
-	}
-	if (opts->subcommand == REPLAY_ROLLBACK)
-		return sequencer_rollback(opts);
-	if (opts->subcommand == REPLAY_CONTINUE)
-		return sequencer_continue(opts);
-
 	for (i = 0; i < opts->revs->pending.nr; i++) {
 		unsigned char sha1[20];
 		const char *name = opts->revs->pending.objects[i].name;
@@ -1155,7 +1381,9 @@ int sequencer_pick_revisions(struct replay_opts *opts)
 		return -1;
 	if (save_opts(opts))
 		return -1;
-	return pick_commits(todo_list, opts);
+	res = pick_commits(&todo_list, opts);
+	todo_list_release(&todo_list);
+	return res;
 }
 
 void append_signoff(struct strbuf *msgbuf, int ignore_footer, unsigned flag)

sequencer.h

@@ -1,10 +1,7 @@
 #ifndef SEQUENCER_H
 #define SEQUENCER_H
 
-#define SEQ_DIR		"sequencer"
-#define SEQ_HEAD_FILE	"sequencer/head"
-#define SEQ_TODO_FILE	"sequencer/todo"
-#define SEQ_OPTS_FILE	"sequencer/opts"
+const char *git_path_seq_dir(void);
 
 #define APPEND_SIGNOFF_DEDUP (1u << 0)
 
@@ -13,16 +10,8 @@ enum replay_action {
 	REPLAY_PICK
 };
 
-enum replay_subcommand {
-	REPLAY_NONE,
-	REPLAY_REMOVE_STATE,
-	REPLAY_CONTINUE,
-	REPLAY_ROLLBACK
-};
-
 struct replay_opts {
 	enum replay_action action;
-	enum replay_subcommand subcommand;
 
 	/* Boolean options */
 	int edit;
@@ -46,9 +35,27 @@ struct replay_opts {
 
 	/* Only used by REPLAY_NONE */
 	struct rev_info *revs;
+
+	/* malloc()ed data entrusted to the sequencer */
+	void **owned;
+	int owned_nr, owned_alloc;
 };
+#define REPLAY_OPTS_INIT { -1 }
+
+/*
+ * Make it the duty of sequencer_remove_state() to release the memory;
+ * For ease of use, return the same pointer.
+ */
+void *sequencer_entrust(struct replay_opts *opts, void *to_free);
 
 int sequencer_pick_revisions(struct replay_opts *opts);
+int sequencer_continue(struct replay_opts *opts);
+int sequencer_rollback(struct replay_opts *opts);
+int sequencer_remove_state(struct replay_opts *opts);
+
+int sequencer_commit(const char *defmsg, struct replay_opts *opts,
+			  int allow_empty, int edit, int amend,
+			  int cleanup_commit_message);
 
 extern const char sign_off_header[];