Re: [RFC PATCH 3/9] rebase -i: comment out squash!/fixup! subjects from squash message

[Taylor Blau <me@ttaylorr.com>]

On Fri, Jan 08, 2021 at 02:53:41PM +0530, Charvi Mendiratta wrote:
> From: Phillip Wood <phillip.wood@dunelm.org.uk>
>
> When squashing commit messages the squash!/fixup! subjects are not of
> interest so comment them out to stop them becoming part of the final
> message.
>
> This change breaks a bunch of --autosquash tests which rely on the
> "squash! <subject>" line appearing in the final commit message. This is
> addressed by adding a second line to the commit message of the "squash!
> ..." commits and testing for that.
>
> Signed-off-by: Phillip Wood <phillip.wood@dunelm.org.uk>
> Signed-off-by: Charvi Mendiratta <charvi077@gmail.com>
> ---
>  sequencer.c                  | 25 ++++++++++++++++++++++++-
>  t/t3415-rebase-autosquash.sh | 27 +++++++++++++--------------
>  t/t3900-i18n-commit.sh       |  4 ----
>  3 files changed, 37 insertions(+), 19 deletions(-)
>
> diff --git a/sequencer.c b/sequencer.c
> index 5062976d10..b050a9a212 100644
> --- a/sequencer.c
> +++ b/sequencer.c
> @@ -1718,15 +1718,38 @@ static int is_pick_or_similar(enum todo_command command)
>  	}
>  }
>
> +static size_t subject_length(const char *body)
> +{
> +	size_t i, len = 0;
> +	char c;
> +	int blank_line = 1;
> +	for (i = 0, c = body[i]; c; c = body[++i]) {
> +		if (c == '\n') {
> +			if (blank_line)
> +				return len;
> +			len = i + 1;
> +			blank_line = 1;
> +		} else if (!isspace(c)) {
> +			blank_line = 0;
> +		}
> +	}
> +	return blank_line ? len : i;
> +}
> +

OK, so this gets the length of the subject in "body", which is defined
as the run of characters before a newline and then a space character. So
"foo bar\n\nbaz" would return 7, but "foo bar\nbaz" would return 11.

Makes sense. (Apologies for stating the obvious here, I just had to read
this function to myself a couple of times to make sure that I understood
what it was doing.)

>  static void append_squash_message(struct strbuf *buf, const char *body,
>  				  struct replay_opts *opts)
>  {
> +	size_t commented_len = 0;
> +
>  	unlink(rebase_path_fixup_msg());
> +	if (starts_with(body, "squash!") || starts_with(body, "fixup!"))
> +		commented_len = subject_length(body);
>  	strbuf_addf(buf, "\n%c ", comment_line_char);
>  	strbuf_addf(buf, _("This is the commit message #%d:"),
>  		    ++opts->current_fixup_count + 1);
>  	strbuf_addstr(buf, "\n\n");
> -	strbuf_addstr(buf, body);
> +	strbuf_add_commented_lines(buf, body, commented_len);
> +	strbuf_addstr(buf, body + commented_len);

Very nice; the subject gets commented when it starts with "squash!" or
"fixup!", but the body remains uncommented. Makes sense to me.

> @@ -224,7 +223,7 @@ test_expect_success 'auto squash that matches longer sha1' '
>  	git cat-file blob HEAD^:file1 >actual &&
>  	test_cmp expect actual &&
>  	git cat-file commit HEAD^ >commit &&
> -	grep squash commit >actual &&
> +	grep "extra para" commit >actual &&
>  	test_line_count = 1 actual
>  '

Worth checking that "squash" doesn't appear in an uncommented part of
actual? Or better yet, checking that "# squash ..." _does_ appear.

I.e., that we would leave this as:

    -	grep squash commit >actual &&
    +	grep "^# squash" commit >actual &&
    +	grep "extra para" commit >actual &&

> @@ -342,8 +341,8 @@ test_expect_success C_LOCALE_OUTPUT 'autosquash with custom inst format' '
>  	git cat-file blob HEAD^:file1 >actual &&
>  	test_cmp expect actual &&
>  	git cat-file commit HEAD^ >commit &&
> -	grep squash commit >actual &&
> -	test_line_count = 2 actual
> +	grep first commit >actual &&
> +	test_line_count = 3 actual
>  '

Ditto.

Thanks,
Taylor