Re: [PATCH 7/7] xdiff: make diff3 the default conflictStyle

[Felipe Contreras <felipe.contreras@gmail.com>]

Elijah Newren wrote:
> On Fri, Jun 11, 2021 at 10:57 AM Felipe Contreras <felipe.contreras@gmail.com> wrote:

> > Or just use the base of the virtual merge:
> > 
> >   <<<<<<< HEAD
> >   D
> >   ||||||| merged common ancestors
> >   1
> >   =======
> >   C
> >   >>>>>>> C
> 
> I think that implementing this choice would look like this (again, not
> compiled or tested and I'm not familiar with xdiff so take it with a
> big grain of salt):
> 
> 
> diff --git a/ll-merge.c b/ll-merge.c
> index 095a4d820e..dbc7f76951 100644
> --- a/ll-merge.c
> +++ b/ll-merge.c
> @@ -130,6 +130,8 @@ static int ll_xdl_merge(const struct ll_merge_driver *drv_unused,
>  	memset(&xmp, 0, sizeof(xmp));
>  	xmp.level = XDL_MERGE_ZEALOUS;
>  	xmp.favor = opts->variant;
> +	if (git_xmerge_style >= 0 && opts->virtual_ancestor)
> +		xmp.favor = XDL_MERGE_FAVOR_BASE;

The only time git_xmerge_style isn't >= 0 is when no merge style has
been configured by the user.

I don't see why this:

  git -c merge.conflictstyle=merge merge

Should have a different behavior than this:

  git merge

In fact, I don't see why any style should change that desired behavior.
If you said there's issues with the "merge" style too, perhaps the above
will help for those cases too.

> > We don't have to use diff3 all the way.
> 
> Right, thus my mention in the other email to consider adding a
> XDL_MERGE_FAVOR_BASE -- which you then also mention here in your third
> option, and which I've now given at least a partial patch for.  Not
> sure if it's a crazy idea or a great idea, since I don't do very many
> criss-cross merges myself.

I thought you meant as a separate configurable flag, not something done
by default.

Now that I understand what you meant I think it could be a great idea.

Cheers.

-- 
Felipe Contreras