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

Phillip Wood wrote:

On 10/06/2021 15:11, Felipe Contreras wrote:

quoted

Phillip Wood wrote:

quoted

On 09/06/2021 20:28, Felipe Contreras wrote:

quoted

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

  % git grep merge_recursive_config
  static void merge_recursive_config(struct merge_options *opt)

For starters it's a static function.

Second, clearly the type of functions git_config() receives are not
`void (*)(struct merge_options *)`.

I mean, I do see value in explaning as much detail as needed in the
commit message, but it shouldn't be a lesson on git's codebase:
git_config() is a standard thing, and it's even mentioned in the user
manual.

https://git-scm.com/docs/user-manual#birdview-on-the-source-code

quoted

That is the problem. I don't know how that's not clear.

quoted

quoted

Therefore builtins like `git merge` can't call this function at the
right time.

  >

quoted

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().

Feel free to write a patch for that.

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.

That is a separate issue, that I already mentioned...

quoted

That problem whoever, is orthogonal to this series.

quoted

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.

here.

-- 
Felipe Contreras