Re: [PATCH 2/2] diff: fix --exit-code with external diff

[phillip.wood123@gmail.com]

Hi René

On 06/05/2024 19:23, René Scharfe wrote:
> Am 05.05.24 um 17:25 schrieb Phillip Wood:
>> Merge strategies are expected to exit 0 on success, 1 when there are
>> conflicts and another non-zero value for other errors - it would be
>> nice to do something similar here where 1 means "there were
>> differences" but it is probably too late to do that without a config
>> value to indicate that we should trust the exit code.
> Right, such a diff command protocol v2 would not need to pipe the
> output through an inspection loop.  Sounds like a good idea.  It's
> unfortunate that it would increase the configuration surface, which is
> not in an acute need to expand.  We could advertise the new option when
> dying due to the unsupported combination of --exit-code and external
> diff, but that's in equal parts helpful and obnoxious, I feel.

Yes, diff dying would be annoying but the message would be useful.

Thinking about the external diff and some of the other diff options I 
wonder what we should do when options like "--quiet" and "--name-only" 
are combined with an external diff (I haven't checked the current 
behavior). If we introduced a diff command protocol v2 we could include 
a way to pass through "--quiet" though maybe just redirecting the stdout 
of the external command to /dev/null and using the exit code would be 
sufficient.

Best Wishes

Phillip

P.S. I haven't forgotten about our unit-test discussion but I'm afraid 
it will probably be the middle of next month before I have time to reply.