Re: Git Merge 2020 slides and reproducibility

> On Sat, Mar 7, 2020 at 5:38 AM Konstantin Tokarev <annulen@yandex.ru> wrote:
>>  06.03.2020, 18:00, "Elijah Newren" <newren@gmail.com>:
>>  > Hi,
>>  >
>>  > Had a few different folks ask me at Git Merge about slides for my
>>  > talk. I said I'd post them on github somewhere, but in case you were
>>  > one of the folks and have a hard time finding it...they are up at
>>  > https://github.com/newren/presentations/blob/pdfs/merge-performance/merge-performance-slides.pdf
>>  > and steps to reproduce the speedups I got can be found at
>>  > https://github.com/newren/git/blob/git-merge-2020-demo/README.md
>>  > (though be forewarned that the code is has lots of fixmes & ifdefs &
>>  > other problems, has awful commit messages, etc.; I will be cleaning it
>>  > up soon).
>>
>>  Hello, I've just tried your branch on my repository and it seems like it can
>>  be a salvation from all rename-related pain that I'm regularly facing when
>>  doing merges and cherry-picks! Thank you very much, I hope it will be
>>  integrated into mainline soon.
>
> Wow, thanks for trying it out. Please note that while it _might_ be
> okay to use for real work, I am not that confident that it is.

> There
> are a number of factors making the 'demo' label I gave it a rather
> fitting one:
>
>   * I only started using it personally on a real world repository (or
> two) about a week and a half ago. (Before then, I knew merge-ort
> didn't work.)
>   * The second real world repo I used it on uncovered a bug in my code
> that the testsuite didn't catch[1]
>   * Although I've tested with two real world repos now, that testing
> was very minimal; I was focused on getting the demo ready and
> implementing as many optimizations as I could.
>   * While the outer merge, rebase, and cherry-pick commands will
> accept a bunch of merge-machinery options and pass them along,
> merge-ort flat ignores them all.
>   * merge-ort is hardcoded for merge.directoryRenames=true, when the
> default should be merge.directoryRenames=conflict

>   * it has a bunch of FIXMEs, some of which are code cleanliness
> issues but some of which represent minor bugs
>
> [1] https://lore.kernel.org/git/911de63afa274b0791e4d4252934a5e9b0031f10.1582762465.git.gitgitgadget@gmail.com/
>
> Also...
>
>>  However, when testing my previous merges which had to be done with helper
>>  script, I've encountered case of
>>
>>  CONFLICT (directory rename split)
>>
>>  Is there any way to prevent conflict in this case if files are the same, and
>>  merge their contents if there are differences? I think it would be reasonable
>>  to assume that move done in newest commit should win, and allow user
>>  to change strategy via command line option, provide explicit hint where files
>>  should be moved, or maybe even decide it interactively.
>
> This conflict message is known to trigger in some cases where it
> shouldn't; it may be that you're just experiencing annoyance from
> that. Let me fix that issue before worrying about workarounds.