Re: [PATCH] rebase -i: allow a comment after a "break" command

> On Thu, Jan 12 2023, Phillip Wood via GitGitGadget wrote:
>
>> From: Phillip Wood <phillip.wood@dunelm.org.uk>
>>
>> When adding a "break" command to a rebase todo list it can be helpful to
>> add a comment as a reminder as to what the user was planning to do when
>> the rebase stopped. Anything following the command is interpreted as an
>> argument to the command and results in an error. Change this so that a
>> "break command may be followed by "# <comment>" in the same way as
>> a "merge" command. Requiring the comment to begin with "# " allows the
>> break command to start taking an argument in the future if that turns
>> out to be useful.
>>
>> Reported-by: Olliver Schinagl <oliver@schinagl.nl>
>> Signed-off-by: Phillip Wood <phillip.wood@dunelm.org.uk>
>> ---
>>      rebase -i: allow a comment after a "break" command
>>      
>>      I'm open to suggestions for other ways to handle comments but copying
>>      what we do to separate merge parents from the merge commit subject
>>      seemed simplest.
>>      
>>      Should this print the comment when stopping for a break command?
>>
>> Published-As: https://github.com/gitgitgadget/git/releases/tag/pr-1460%2Fphillipwood%2Fsequencer-allow-comment-after-break-v1
>> Fetch-It-Via: git fetch https://github.com/gitgitgadget/git pr-1460/phillipwood/sequencer-allow-comment-after-break-v1
>> Pull-Request: https://github.com/gitgitgadget/git/pull/1460
>>
>>   Documentation/git-rebase.txt |  4 +++-
>>   sequencer.c                  |  7 +++++--
>>   t/lib-rebase.sh              |  2 +-
>>   t/t3418-rebase-continue.sh   | 16 ++++++++++++++++
>>   4 files changed, 25 insertions(+), 4 deletions(-)
>>
>> diff --git a/Documentation/git-rebase.txt b/Documentation/git-rebase.txt
>> index f9675bd24e6..511ace43db0 100644
>> --- a/Documentation/git-rebase.txt
>> +++ b/Documentation/git-rebase.txt
>> @@ -869,7 +869,9 @@ 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.
>> +cherry-picking any commit first), use the "break" command. A "break"
>> +command may be followed by a comment beginning with `#` followed by a
>> +space.
> You're missing a corresponding edit here to the help string in
> append_todo_help(), as you note you're making "break" support what
> "merge" does, and that help string documents that "merge" accepts a
> comment, after this we don't do that for "break", but should one way or
> the other (see below).
>
>> --- a/sequencer.c
>> +++ b/sequencer.c
>> @@ -2509,7 +2509,9 @@ static int parse_insn_line(struct repository *r, struct todo_item *item,
>>   	padding = strspn(bol, " \t");
>>   	bol += padding;
>>   
>> -	if (item->command == TODO_NOOP || item->command == TODO_BREAK) {
>> +	if (item->command == TODO_NOOP ||
>> +	    (item->command == TODO_BREAK &&
>> +	     (bol[0] != '#' || (bol[1] && !isspace (bol[1]))))) {
>>   		if (bol != eol)
>>   			return error(_("%s does not accept arguments: '%s'"),
>>   				     command_to_string(item->command), bol);
>> @@ -2524,7 +2526,8 @@ static int parse_insn_line(struct repository *r, struct todo_item *item,
>>   			     command_to_string(item->command));
>>   
>>   	if (item->command == TODO_EXEC || item->command == TODO_LABEL ||
>> -	    item->command == TODO_RESET || item->command == TODO_UPDATE_REF) {
>> +	    item->command == TODO_RESET || item->command == TODO_UPDATE_REF ||
>> +	    item->command == TODO_BREAK) {
>>   		item->commit = NULL;
>>   		item->arg_offset = bol - buf;
>>   		item->arg_len = (int)(eol - bol);
>> diff --git a/t/lib-rebase.sh b/t/lib-rebase.sh
>> index b57541356bd..a648013f299 100644
>> --- a/t/lib-rebase.sh
>> +++ b/t/lib-rebase.sh
>> @@ -51,7 +51,7 @@ set_fake_editor () {
>>   		case $line in
>>   		pick|p|squash|s|fixup|f|edit|e|reword|r|drop|d|label|l|reset|r|merge|m)
>>   			action="$line";;
>> -		exec_*|x_*|break|b)
>> +		exec_*|x_*|break_*|b_*|break|b)
>>   			echo "$line" | sed 's/_/ /g' >> "$1";;
>>   		merge_*|fixup_*)
>>   			action=$(echo "$line" | sed 's/_/ /g');;
>> diff --git a/t/t3418-rebase-continue.sh b/t/t3418-rebase-continue.sh
>> index 130e2f9b553..18d82869b38 100755
>> --- a/t/t3418-rebase-continue.sh
>> +++ b/t/t3418-rebase-continue.sh
>> @@ -266,6 +266,22 @@ test_expect_success 'the todo command "break" works' '
>>   	test_path_is_file execed
>>   '
>>   
>> +test_expect_success 'the todo command "break" accepts a comment' '
>> +	rm -f execed &&
>> +	test_write_lines "break # comment" "break #" "exec >execed" >expect &&
>> +	write_script cat-todo.sh <<-\EOS &&
>> +	GIT_SEQUENCE_EDITOR="grep ^\[^#\]" git rebase --edit-todo >actual
>> +	EOS
>> +	FAKE_LINES="exec_./cat-todo.sh break_#_comment b_# exec_>execed" \
>> +		git rebase -i HEAD &&
>> +	test_cmp expect actual &&
>> +	test_path_is_missing execed &&
>> +	git rebase --continue &&
>> +	test_path_is_missing execed &&
>> +	git rebase --continue &&
>> +	test_path_is_file execed
>> +'
>> +
>>   test_expect_success '--reschedule-failed-exec' '
>>   	test_when_finished "git rebase --abort" &&
>>   	test_must_fail git rebase -x false --reschedule-failed-exec HEAD^ &&
>>
>> base-commit: 8a4e8f6a67e7fc97048d4666eec38399b88e0e3b
> I like this direction, but I don't see why we need to continue this
> special-snowflakeness of only allowing specific commands to accept these
> #-comments.

>
> Why not just have them all support it? It started with "merge", which as
> 4c68e7ddb59 (sequencer: introduce the `merge` command, 2018-04-25) note
> can be used for:
>
> 	merge -C baaabaaa abc # Merge the branch 'abc' into master
>
> As Olliver points out we should probably support "#" without the
> following " ", which seems to be an accident of history &
> over-strictness.

>
> But in this commit you extend it to "break", but we're going out of or
> way to e.g. extend this to "noop".
>
> So I'd expect that just like the first for-loop in "parse_insn_line()"
> we'd check if strchr(bol, '#') returns non-NULL, and if so set eol to
> that result.
>
> The "just like" being that we may want to explicitly forbid this or
> handle it specially for some, e.g. I didn't check but do the "label" and
> "reset" perhaps support arbitrary non-'\n' (probably by accident, and we
> could support commments there too).
>
> For "pick" we probably need to explicitly exclude it, although I can't
> remember if we do anything useful with the part of the line after the
> OID (maybe not...).