Re: [RFC PATCH, WAS: "weird diff output?" 2/2] xdiff: implement empty line chunk heuristic

From: Junio C Hamano <gitster@pobox.com>
Date: Apr 15, 2016, 20:30 UTC
Message-ID: <xmqqzisuaa3t.fsf@gitster.mtv.corp.google.com>
In-Reply-To: <CA+P7+xoWbrSaONH5xq=w5W190Jknk0Qsc5brS4UKFAs2_dTceg@mail.gmail.com>

Jacob Keller <jacob.keller@gmail.com> writes:

Show 17 quoted lines

> On Fri, Apr 15, 2016 at 1:06 PM, Junio C Hamano <gitster@pobox.com> wrote:
>
>> I actually do not think these knobs should exist when the code is
>> mature enough to be shipped to the end users.
>>
>> Use "diff.compactionHeuristics = <uint>" as an opaque set of bits to
>> help the developers while they compare notes and reach consensus on
>> a single tweak that they can agree on being good enough, and then
>> remove that variable before the code hits 'next'.
>>
>> Thanks.
>
> I was under the impression that we would want a longer lived
> configuration until we had enough data to say whether it was
> helpful to make it default. I guess i had thought it would need to
> be longer lived since there may be cases where it's not optimal
> and being able to turn it off would be good?

Once you start worrying about "some cases this may misbehave", a configuration variable is a wrong mechanism to do so anyway. You would need to tie this to attributes, so the users can say "use this heuristics for my C code, but do not apply it for my AsciiDoc input", etc.

What you have is a pure developer support; aim to come up with "good enough" way, giving developers an easier way to experiment with, and remove it before the feature is shipped to the end user.