Re: [PATCH 4/7] checkout: fix merge.conflictstyle handling

[Phillip Wood <phillip.wood123@gmail.com>]

On 10/06/2021 15:11, Felipe Contreras wrote:
> Phillip Wood wrote:
>> On 09/06/2021 20:28, Felipe Contreras wrote:
>>> Currently both merge.conflictStyle and `git commit --merge
>>> --conflict=diff3` don't work together, since the former wrongly
>>> overrides the later.
>>>
>>> The way merge configurations are handled is not correct.
>>> It should be possible to do git_config(merge_recursive_config, ...) just
>>> like we can with git_diff_basic_config and others.
>>
>> It would be helpful to explain what the problem with
>> merge_recursive_config() actually is rather than just saying "it should
>> be possible ..."
> 
> The problem is that you can't do this:
> 
>    git_config(merge_recursive_config, NULL);
> 
> As it was explained.

You do not explain why you cannot do that

> That is the problem. I don't know how that's not clear.
> 
>>> Therefore builtins like `git merge` can't call this function at the
>>> right time.
>>   >
>>> We shuffle the functions a little bit so at least merge_recursive_config
>>> doesn't call git_xmerge_config directly and thus override previous
>>> configurations.
>>
>> Rather than papering of the problem, how difficult would it be to add a
>> field to ll_merge_options and pass the conflict style with that rather
>> than fiddling with the order that we set a global variable.
> 
> Probably not that difficult, but then we also need a parser that
> converts from "diff3" to whatever values we decide in that new field. We
> would need a new parse_config_conflict_style() function.
> And that function will be only used by `git checkout` and nothing else.
> So I don't think there's much value in it.

It would allow us to add a --conflict option to all the mergey commands 
in the future and would be much easier to reason about than the approach 
of juggling where we call git_xmerge_config(). This patch requires us to 
audit all the code paths that end up in merge_recursive_config() to make 
sure they now call git_xmerge_config() themselves. You don't seem to 
have done that as you don't know if am/apply are affected or not.


Best Wishes

Phillip

> That problem whoever, is orthogonal to this series.
> 
>> Does this change affect 'am/apply -3'? - Do they still read the config
>> setting properly?
> 
> Good question. I'll have to add more tests to make sure that works
> properly.
> 
> Cheers.
>