1 files changed, 132 insertions, 48 deletions

diff --git a/builtin/revert.c b/builtin/revert.c
index 87df70edc3..1ea525c10e 100644
--- a/builtin/revert.c
+++ b/builtin/revert.c
@@ -40,7 +40,12 @@ static const char * const cherry_pick_usage[] = {
 };
 
 enum replay_action { REVERT, CHERRY_PICK };
-enum replay_subcommand { REPLAY_NONE, REPLAY_RESET, REPLAY_CONTINUE };
+enum replay_subcommand {
+	REPLAY_NONE,
+	REPLAY_REMOVE_STATE,
+	REPLAY_CONTINUE,
+	REPLAY_ROLLBACK
+};
 
 struct replay_opts {
 	enum replay_action action;
@@ -133,11 +138,13 @@ static void parse_args(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);
-	int reset = 0;
+	int remove_state = 0;
 	int contin = 0;
+	int rollback = 0;
 	struct option options[] = {
-		OPT_BOOLEAN(0, "reset", &reset, "forget the current operation"),
-		OPT_BOOLEAN(0, "continue", &contin, "continue the current operation"),
+		OPT_BOOLEAN(0, "quit", &remove_state, "end revert or cherry-pick sequence"),
+		OPT_BOOLEAN(0, "continue", &contin, "resume revert or cherry-pick sequence"),
+		OPT_BOOLEAN(0, "abort", &rollback, "cancel revert or cherry-pick sequence"),
 		OPT_BOOLEAN('n', "no-commit", &opts->no_commit, "don't automatically commit"),
 		OPT_BOOLEAN('e', "edit", &opts->edit, "edit the commit message"),
 		OPT_NOOP_NOARG('r', NULL),
@@ -168,25 +175,32 @@ static void parse_args(int argc, const char **argv, struct replay_opts *opts)
 
 	/* Check for incompatible subcommands */
 	verify_opt_mutually_compatible(me,
-				"--reset", reset,
+				"--quit", remove_state,
 				"--continue", contin,
+				"--abort", rollback,
 				NULL);
 
 	/* Set the subcommand */
-	if (reset)
-		opts->subcommand = REPLAY_RESET;
+	if (remove_state)
+		opts->subcommand = REPLAY_REMOVE_STATE;
 	else if (contin)
 		opts->subcommand = REPLAY_CONTINUE;
+	else if (rollback)
+		opts->subcommand = REPLAY_ROLLBACK;
 	else
 		opts->subcommand = REPLAY_NONE;
 
 	/* Check for incompatible command line arguments */
 	if (opts->subcommand != REPLAY_NONE) {
 		char *this_operation;
-		if (opts->subcommand == REPLAY_RESET)
-			this_operation = "--reset";
-		else
+		if (opts->subcommand == REPLAY_REMOVE_STATE)
+			this_operation = "--quit";
+		else if (opts->subcommand == REPLAY_CONTINUE)
 			this_operation = "--continue";
+		else {
+			assert(opts->subcommand == REPLAY_ROLLBACK);
+			this_operation = "--abort";
+		}
 
 		verify_opt_compatible(me, this_operation,
 				"--no-commit", opts->no_commit,
@@ -286,19 +300,20 @@ static char *get_encoding(const char *message)
 	return NULL;
 }
 
-static void write_cherry_pick_head(struct commit *commit)
+static void write_cherry_pick_head(struct commit *commit, const char *pseudoref)
 {
+	const char *filename;
 	int fd;
 	struct strbuf buf = STRBUF_INIT;
 
 	strbuf_addf(&buf, "%s\n", sha1_to_hex(commit->object.sha1));
 
-	fd = open(git_path("CHERRY_PICK_HEAD"), O_WRONLY | O_CREAT, 0666);
+	filename = git_path("%s", pseudoref);
+	fd = open(filename, O_WRONLY | O_CREAT, 0666);
 	if (fd < 0)
-		die_errno(_("Could not open '%s' for writing"),
-			  git_path("CHERRY_PICK_HEAD"));
+		die_errno(_("Could not open '%s' for writing"), filename);
 	if (write_in_full(fd, buf.buf, buf.len) != buf.len || close(fd))
-		die_errno(_("Could not write to '%s'"), git_path("CHERRY_PICK_HEAD"));
+		die_errno(_("Could not write to '%s'"), filename);
 	strbuf_release(&buf);
 }
 
@@ -331,7 +346,7 @@ static void write_message(struct strbuf *msgbuf, const char *filename)
 	int msg_fd = hold_lock_file_for_update(&msg_file, filename,
 					       LOCK_DIE_ON_ERROR);
 	if (write_in_full(msg_fd, msgbuf->buf, msgbuf->len) < 0)
-		die_errno(_("Could not write to %s."), filename);
+		die_errno(_("Could not write to %s"), filename);
 	strbuf_release(msgbuf);
 	if (commit_lock_file(&msg_file) < 0)
 		die(_("Error wrapping up %s"), filename);
@@ -593,7 +608,9 @@ static int do_pick_commit(struct commit *commit, struct replay_opts *opts)
 	 * write it at all.
 	 */
 	if (opts->action == CHERRY_PICK && !opts->no_commit && (res == 0 || res == 1))
-		write_cherry_pick_head(commit);
+		write_cherry_pick_head(commit, "CHERRY_PICK_HEAD");
+	if (opts->action == REVERT && ((opts->no_commit && res == 0) || res == 1))
+		write_cherry_pick_head(commit, "REVERT_HEAD");
 
 	if (res) {
 		error(opts->action == REVERT
@@ -767,7 +784,7 @@ static void read_populate_todo(struct commit_list **todo_list,
 
 	fd = open(todo_file, O_RDONLY);
 	if (fd < 0)
-		die_errno(_("Could not open %s."), todo_file);
+		die_errno(_("Could not open %s"), todo_file);
 	if (strbuf_read(&buf, fd, 0) < 0) {
 		close(fd);
 		strbuf_release(&buf);
@@ -842,10 +859,13 @@ static int create_seq_dir(void)
 {
 	const char *seq_dir = git_path(SEQ_DIR);
 
-	if (file_exists(seq_dir))
-		return error(_("%s already exists."), seq_dir);
+	if (file_exists(seq_dir)) {
+		error(_("a cherry-pick or revert is already in progress"));
+		advise(_("try \"git cherry-pick (--continue | --quit | --abort)\""));
+		return -1;
+	}
 	else if (mkdir(seq_dir, 0777) < 0)
-		die_errno(_("Could not create sequencer directory '%s'."), seq_dir);
+		die_errno(_("Could not create sequencer directory %s"), seq_dir);
 	return 0;
 }
 
@@ -859,11 +879,77 @@ static void save_head(const char *head)
 	fd = hold_lock_file_for_update(&head_lock, head_file, LOCK_DIE_ON_ERROR);
 	strbuf_addf(&buf, "%s\n", head);
 	if (write_in_full(fd, buf.buf, buf.len) < 0)
-		die_errno(_("Could not write to %s."), head_file);
+		die_errno(_("Could not write to %s"), head_file);
 	if (commit_lock_file(&head_lock) < 0)
 		die(_("Error wrapping up %s."), head_file);
 }
 
+static int reset_for_rollback(const unsigned char *sha1)
+{
+	const char *argv[4];	/* reset --merge <arg> + NULL */
+	argv[0] = "reset";
+	argv[1] = "--merge";
+	argv[2] = sha1_to_hex(sha1);
+	argv[3] = NULL;
+	return run_command_v_opt(argv, RUN_GIT_CMD);
+}
+
+static int rollback_single_pick(void)
+{
+	unsigned char head_sha1[20];
+
+	if (!file_exists(git_path("CHERRY_PICK_HEAD")) &&
+	    !file_exists(git_path("REVERT_HEAD")))
+		return error(_("no cherry-pick or revert in progress"));
+	if (!resolve_ref("HEAD", head_sha1, 0, NULL))
+		return error(_("cannot resolve HEAD"));
+	if (is_null_sha1(head_sha1))
+		return error(_("cannot abort from a branch yet to be born"));
+	return reset_for_rollback(head_sha1);
+}
+
+static int sequencer_rollback(struct replay_opts *opts)
+{
+	const char *filename;
+	FILE *f;
+	unsigned char sha1[20];
+	struct strbuf buf = STRBUF_INIT;
+
+	filename = git_path(SEQ_HEAD_FILE);
+	f = fopen(filename, "r");
+	if (!f && errno == ENOENT) {
+		/*
+		 * There is no multiple-cherry-pick in progress.
+		 * If CHERRY_PICK_HEAD or REVERT_HEAD indicates
+		 * a single-cherry-pick in progress, abort that.
+		 */
+		return rollback_single_pick();
+	}
+	if (!f)
+		return error(_("cannot open %s: %s"), filename,
+						strerror(errno));
+	if (strbuf_getline(&buf, f, '\n')) {
+		error(_("cannot read %s: %s"), filename, ferror(f) ?
+			strerror(errno) : _("unexpected end of file"));
+		fclose(f);
+		goto fail;
+	}
+	fclose(f);
+	if (get_sha1_hex(buf.buf, sha1) || buf.buf[40] != '\0') {
+		error(_("stored pre-cherry-pick HEAD file '%s' is corrupt"),
+			filename);
+		goto fail;
+	}
+	if (reset_for_rollback(sha1))
+		goto fail;
+	remove_sequencer_state(1);
+	strbuf_release(&buf);
+	return 0;
+fail:
+	strbuf_release(&buf);
+	return -1;
+}
+
 static void save_todo(struct commit_list *todo_list, struct replay_opts *opts)
 {
 	const char *todo_file = git_path(SEQ_TODO_FILE);
@@ -876,7 +962,7 @@ static void save_todo(struct commit_list *todo_list, struct replay_opts *opts)
 		die(_("Could not format %s."), todo_file);
 	if (write_in_full(fd, buf.buf, buf.len) < 0) {
 		strbuf_release(&buf);
-		die_errno(_("Could not write to %s."), todo_file);
+		die_errno(_("Could not write to %s"), todo_file);
 	}
 	if (commit_lock_file(&todo_lock) < 0) {
 		strbuf_release(&buf);
@@ -964,43 +1050,41 @@ static int pick_revisions(struct replay_opts *opts)
 	 * cherry-pick should be handled differently from an existing
 	 * one that is being continued
 	 */
-	if (opts->subcommand == REPLAY_RESET) {
+	if (opts->subcommand == REPLAY_REMOVE_STATE) {
 		remove_sequencer_state(1);
 		return 0;
-	} else if (opts->subcommand == REPLAY_CONTINUE) {
+	}
+	if (opts->subcommand == REPLAY_ROLLBACK)
+		return sequencer_rollback(opts);
+	if (opts->subcommand == REPLAY_CONTINUE) {
 		if (!file_exists(git_path(SEQ_TODO_FILE)))
-			goto error;
+			return error(_("No %s in progress"), action_name(opts));
 		read_populate_opts(&opts);
 		read_populate_todo(&todo_list, opts);
 
 		/* Verify that the conflict has been resolved */
 		if (!index_differs_from("HEAD", 0))
 			todo_list = todo_list->next;
-	} else {
-		/*
-		 * Start a new cherry-pick/ revert sequence; but
-		 * first, make sure that an existing one isn't in
-		 * progress
-		 */
+		return pick_commits(todo_list, opts);
+	}
 
-		walk_revs_populate_todo(&todo_list, opts);
-		if (create_seq_dir() < 0) {
-			error(_("A cherry-pick or revert is in progress."));
-			advise(_("Use --continue to continue the operation"));
-			advise(_("or --reset to forget about it"));
-			return -1;
-		}
-		if (get_sha1("HEAD", sha1)) {
-			if (opts->action == REVERT)
-				return error(_("Can't revert as initial commit"));
-			return error(_("Can't cherry-pick into empty head"));
-		}
-		save_head(sha1_to_hex(sha1));
-		save_opts(opts);
+	/*
+	 * Start a new cherry-pick/ revert sequence; but
+	 * first, make sure that an existing one isn't in
+	 * progress
+	 */
+
+	walk_revs_populate_todo(&todo_list, opts);
+	if (create_seq_dir() < 0)
+		return -1;
+	if (get_sha1("HEAD", sha1)) {
+		if (opts->action == REVERT)
+			return error(_("Can't revert as initial commit"));
+		return error(_("Can't cherry-pick into empty head"));
 	}
+	save_head(sha1_to_hex(sha1));
+	save_opts(opts);
 	return pick_commits(todo_list, opts);
-error:
-	return error(_("No %s in progress"), action_name(opts));
 }
 
 int cmd_revert(int argc, const char **argv, const char *prefix)