Re: [PATCH] rebase -i: fix numbering in squash message

> 
> Phillip Wood <phillip.wood@talktalk.net> writes:
> 
>> From: Phillip Wood <phillip.wood@dunelm.org.uk>
>>
>> Commit e12a7ef597 ("rebase -i: Handle "combination of <n> commits" with
>> GETTEXT_POISON", 2018-04-27) changed the way that individual commit
>> messages are labelled when squashing commits together. In doing so a
>> regression was introduced where the numbering of the messages is off by
>> one. This commit fixes that and adds a test for the numbering.
>>
>> Signed-off-by: Phillip Wood <phillip.wood@dunelm.org.uk>
>> ---
>>  sequencer.c                | 4 ++--
>>  t/t3418-rebase-continue.sh | 4 +++-
>>  2 files changed, 5 insertions(+), 3 deletions(-)
>>
>> diff --git a/sequencer.c b/sequencer.c
>> index 2eb5ec7227..77d3c2346f 100644
>> --- a/sequencer.c
>> +++ b/sequencer.c
>> @@ -1387,13 +1387,13 @@ static int update_squash_messages(enum todo_command command,
>>  		unlink(rebase_path_fixup_msg());
>>  		strbuf_addf(&buf, "\n%c ", comment_line_char);
>>  		strbuf_addf(&buf, _("This is the commit message #%d:"),
>> -			    ++opts->current_fixup_count);
>> +			    ++opts->current_fixup_count + 1);
>>  		strbuf_addstr(&buf, "\n\n");
>>  		strbuf_addstr(&buf, body);
>>  	} else if (command == TODO_FIXUP) {
>>  		strbuf_addf(&buf, "\n%c ", comment_line_char);
>>  		strbuf_addf(&buf, _("The commit message #%d will be skipped:"),
>> -			    ++opts->current_fixup_count);
>> +			    ++opts->current_fixup_count + 1);
>>  		strbuf_addstr(&buf, "\n\n");
>>  		strbuf_add_commented_lines(&buf, body, strlen(body));
>>  	} else
> 
> Good spotting.  When viewed in a wider context (e.g. "git show -W"
> after applying this patch), the way opts->current_fixup_count is
> used is somewhat incoherent and adding 1 to pre-increment would make
> it even more painful to read.  Given that there already is
> 
> 		strbuf_addf(&header, _("This is a combination of %d commits."),
> 			    opts->current_fixup_count + 2);
> 
> before this part, the code should make it clear these three places
> refer to the same number for it to be readable.
> 
> I wonder if it makes it easier to read, understand and maintain if
> there were a local variable that gets opts->current_fixup_count+2 at
> the beginning of the function, make these three places refer to that
> variable, and move the increment of opts->current_fixup_count down
> in the function, after the "if we are squashing, do this, if we are
> fixing up, do that, otherwise, we do not know what we are doing"
> cascade.  And use the more common post-increment, as we no longer
> depend on the returned value while at it.
> 
> IOW, something like this (untested), on top of yours.

> 
>  sequencer.c | 10 ++++++----
>  1 file changed, 6 insertions(+), 4 deletions(-)
> 
> diff --git a/sequencer.c b/sequencer.c
> index 77d3c2346f..f82c283a89 100644
> --- a/sequencer.c
> +++ b/sequencer.c
> @@ -1331,8 +1331,9 @@ static int update_squash_messages(enum todo_command command,
>  	struct strbuf buf = STRBUF_INIT;
>  	int res;
>  	const char *message, *body;
> +	int fixup_count = opts->current_fixup_count + 2;
>  
> -	if (opts->current_fixup_count > 0) {
> +	if (fixup_count > 2) {
>  		struct strbuf header = STRBUF_INIT;
>  		char *eol;
>  
> @@ -1345,7 +1346,7 @@ static int update_squash_messages(enum todo_command command,
>  
>  		strbuf_addf(&header, "%c ", comment_line_char);
>  		strbuf_addf(&header, _("This is a combination of %d commits."),
> -			    opts->current_fixup_count + 2);
> +			    fixup_count);
>  		strbuf_splice(&buf, 0, eol - buf.buf, header.buf, header.len);
>  		strbuf_release(&header);
>  	} else {
> @@ -1387,18 +1388,19 @@ static int update_squash_messages(enum todo_command command,
>  		unlink(rebase_path_fixup_msg());
>  		strbuf_addf(&buf, "\n%c ", comment_line_char);
>  		strbuf_addf(&buf, _("This is the commit message #%d:"),
> -			    ++opts->current_fixup_count + 1);
> +			    fixup_count);
>  		strbuf_addstr(&buf, "\n\n");
>  		strbuf_addstr(&buf, body);
>  	} else if (command == TODO_FIXUP) {
>  		strbuf_addf(&buf, "\n%c ", comment_line_char);
>  		strbuf_addf(&buf, _("The commit message #%d will be skipped:"),
> -			    ++opts->current_fixup_count + 1);
> +			    fixup_count);
>  		strbuf_addstr(&buf, "\n\n");
>  		strbuf_add_commented_lines(&buf, body, strlen(body));
>  	} else
>  		return error(_("unknown command: %d"), command);
>  	unuse_commit_buffer(commit, message);
> +	opts->current_fixup_count++;
>  
>  	res = write_message(buf.buf, buf.len, rebase_path_squash_msg(), 0);
>  	strbuf_release(&buf);
> 
>