Re: [PATCH 2/2] merge: make sure to terminate message with newline

[Luca Weiss <luca@z3ntu.xyz>]

On Samstag, 17. Juli 2021 19:47:20 CEST Jeff King wrote:
> On Sat, Jul 17, 2021 at 02:40:55PM +0100, Phillip Wood wrote:
> > > which would cover that case. But Phillip mentioned that our own
> > > fmt_merge_msg() does not include a newline.
> > 
> > I mentioned that we remove the newline that is added by fmt_merge_msg(),
> > not that there is no newline added by fmt_merge_msg() - maybe I wasn't
> > clear enough. In builtin/merge.c:prepare_merge_message() we do
> > 
> > 	fmt_merge_msg(merge_names, merge_msg, &opts);
> > 	if (merge_msg->len)
> > 	
> > 		strbuf_setlen(merge_msg, merge_msg->len - 1);
> 
> Of maybe I didn't read carefully enough. :)
> 
> Either way, thanks for clarifying. Doing something like:
> 
>   cat >.git/hooks/commit-msg <<\EOF
>   #!/bin/sh
>   xxd "$1"
>   EOF
>   chmod +x .git/hooks/commit-msg
> 
>   git merge --no-edit ...
> 
> shows off the problem; the hook sees that intermediate state.
> 
> Likewise if we do:
> 
>   git merge -m "foo" ...
> 
> which similarly suppresses the editor. There are actually two
> interesting cases here:
> 
>   - if merge.log is not set, then we'd see "foo" with no newline
> 
>   - if it is set, we'll get a newline after "foo", but with no newline
>     after the log data
> 
> Likewise for:
> 
>   printf foo >no-newline
>   git merge -F no-newline ...
> 
> So I think we'd probably want to see a 3-patch series:
> 
>   1. Make interpret-trailers handle input missing the final newline.
>      This isn't strictly necessary after patches 2 and 3, but it makes
>      sense to be more robust with unexpected input.
> 
>   2. Drop the newline-stripping from prepare_merge_message(). The
>      examples above show some ways we could cover this in the tests.
>      This will help --no-edit case, but also using merge.log with "-m"
>      or "-F".
> 
>   3. Teach prepare_to_commit() to add the extra newline before letting
>      hooks see the message. This should probably be done only when
>      cleanup_mode != COMMIT_MSG_CLEANUP_NONE.
> 
> Luca, do you want to try revising your series in that direction?
> 
> -Peff

Hi Peff,

if you have a good idea on how to create these patches, feel free to do so.
If not, I can take a shot at it this or next week.

Regards
Luca