Re: [BUG-ish] diff compaction heuristic false positive

> On Fri, Jun 10, 2016 at 03:50:43AM -0400, Jeff King wrote:
>
>> I found a false positive with the new compaction heuristic in v2.9:
>> [...]
>
> And by the way, this is less "hey neat, I found a case" and more "wow,
> this is a lot worse than I thought".
>
> I diffed the old and new output for the top 10,000 commits in this
> particular ruby code base. There were 45 commits with changed diffs.
> Spot-checking them manually, a little over 1/3 of them featured this bad
> pattern. The others looked like strict improvements.
>
> That's a lot worse than the outcomes we saw on other code bases earlier.
> 1/3 bad is still a net improvement, so I dunno. Is this worth worrying
> about? Should we bring back the documentation for the knob to disable
> it? Should we consider making it tunable via gitattributes?
>
> I don't think that last one really helps; the good cases _and_ the bad
> ones are both in ruby code (though certainly the C code we looked at
> earlier was all good).
>
> It may also be possible to make it Just Work by using extra information
> like indentation. I haven't thought hard enough about that to say.
>
> -Peff