Merge branch 'js/rebase-i-break'

"git rebase -i" learned a new insn, 'break', that the user can
insert in the to-do list.  Upon hitting it, the command returns
control back to the user.

* js/rebase-i-break:
  rebase -i: introduce the 'break' command
  rebase -i: clarify what happens on a failed `exec`

Documentation/git-rebase.txt

@@ -441,7 +441,8 @@ See also INCOMPATIBLE OPTIONS below.
 --exec <cmd>::
 	Append "exec <cmd>" after each line creating a commit in the
 	final history. <cmd> will be interpreted as one or more shell
-	commands.
+	commands. Any command that fails will interrupt the rebase,
+	with exit code 1.
 +
 You may execute several commands by either using one instance of `--exec`
 with several commands:
@@ -641,6 +642,9 @@ By replacing the command "pick" with the command "edit", you can tell
 the files and/or the commit message, amend the commit, and continue
 rebasing.
 
+To interrupt the rebase (just like an "edit" command would do, but without
+cherry-picking any commit first), use the "break" command.
+
 If you just want to edit the commit message for a commit, replace the
 command "pick" with the command "reword".
 

rebase-interactive.c

@@ -14,6 +14,7 @@ void append_todo_help(unsigned edit_todo, unsigned keep_empty,
 "s, squash <commit> = use commit, but meld into previous commit\n"
 "f, fixup <commit> = like \"squash\", but discard this commit's log message\n"
 "x, exec <command> = run command (the rest of the line) using shell\n"
+"b, break = stop here (continue rebase later with 'git rebase --continue')\n"
 "d, drop <commit> = remove commit\n"
 "l, label <label> = label current HEAD with a name\n"
 "t, reset <label> = reset HEAD to a label\n"

sequencer.c

@@ -1458,6 +1458,7 @@ enum todo_command {
 	TODO_SQUASH,
 	/* commands that do something else than handling a single commit */
 	TODO_EXEC,
+	TODO_BREAK,
 	TODO_LABEL,
 	TODO_RESET,
 	TODO_MERGE,
@@ -1479,6 +1480,7 @@ static struct {
 	{ 'f', "fixup" },
 	{ 's', "squash" },
 	{ 'x', "exec" },
+	{ 'b', "break" },
 	{ 'l', "label" },
 	{ 't', "reset" },
 	{ 'm', "merge" },
@@ -2004,7 +2006,7 @@ static int parse_insn_line(struct todo_item *item, const char *bol, char *eol)
 	padding = strspn(bol, " \t");
 	bol += padding;
 
-	if (item->command == TODO_NOOP) {
+	if (item->command == TODO_NOOP || item->command == TODO_BREAK) {
 		if (bol != eol)
 			return error(_("%s does not accept arguments: '%s'"),
 				     command_to_string(item->command), bol);
@@ -3393,6 +3395,24 @@ static int checkout_onto(struct replay_opts *opts,
 	return update_ref(NULL, "ORIG_HEAD", &oid, NULL, 0, UPDATE_REFS_MSG_ON_ERR);
 }
 
+static int stopped_at_head(void)
+{
+	struct object_id head;
+	struct commit *commit;
+	struct commit_message message;
+
+	if (get_oid("HEAD", &head) ||
+	    !(commit = lookup_commit(the_repository, &head)) ||
+	    parse_commit(commit) || get_message(commit, &message))
+		fprintf(stderr, _("Stopped at HEAD\n"));
+	else {
+		fprintf(stderr, _("Stopped at %s\n"), message.label);
+		free_message(commit, &message);
+	}
+	return 0;
+
+}
+
 static const char rescheduled_advice[] =
 N_("Could not execute the todo command\n"
 "\n"
@@ -3439,6 +3459,9 @@ static int pick_commits(struct todo_list *todo_list, struct replay_opts *opts)
 			unlink(rebase_path_stopped_sha());
 			unlink(rebase_path_amend());
 			delete_ref(NULL, "REBASE_HEAD", NULL, REF_NO_DEREF);
+
+			if (item->command == TODO_BREAK)
+				return stopped_at_head();
 		}
 		if (item->command <= TODO_SQUASH) {
 			if (is_rebase_i(opts))

t/lib-rebase.sh

@@ -49,7 +49,7 @@ set_fake_editor () {
 		case $line in
 		pick|squash|fixup|edit|reword|drop)
 			action="$line";;
-		exec*)
+		exec*|break)
 			echo "$line" | sed 's/_/ /g' >> "$1";;
 		"#")
 			echo '# comment' >> "$1";;

t/t3418-rebase-continue.sh

@@ -241,5 +241,14 @@ test_rerere_autoupdate -m
 GIT_SEQUENCE_EDITOR=: && export GIT_SEQUENCE_EDITOR
 test_rerere_autoupdate -i
 test_rerere_autoupdate --preserve-merges
+unset GIT_SEQUENCE_EDITOR
+
+test_expect_success 'the todo command "break" works' '
+	rm -f execed &&
+	FAKE_LINES="break exec_>execed" git rebase -i HEAD &&
+	test_path_is_missing execed &&
+	git rebase --continue &&
+	test_path_is_file execed
+'
 
 test_done