Shake fails test with GHC 7.10 RC3

[Neil Mitchell]

Interesting result. I've just attached a much smaller test case to the
ticket - it would be good to see if that fails or passes with RC2, or
breaks at the same point.

The fact that there does seem to be a regression between RC2 and RC3
(either a regression itself, or making a previous bug easier to hit)
makes me think that a release might not be such a great idea.

Thanks, Neil


On Sat, Mar 21, 2015 at 11:35 AM, Herbert Valerio Riedel
<hvriedel at gmail.com> wrote:
> On 2015-03-21 at 08:21:20 +0100, Herbert Valerio Riedel wrote:
>> On 2015-03-21 at 07:56:32 +0100, Neil Mitchell wrote:
>>
>> [...]
>>
>>> 3) I tested with GHC RC1 and GHC RC2, both of which were fine. The fact no
>>> one else hit this with RC2 might just be because its a very recent
>>> regression.
>>
>> We -- and by that I don't mean myself... :) -- could git-bisect between
>> RC2 and RC3 here (semi-)automatically (i.e. maybe unattended if it's
>> scriptable) if your test-case (even if it's not minimal) reliably
>> triggers the bug...
>
> I scripted up a test and git-bisected between RC2 and RC3, and the
> following commit is the one where `shake-test oracle test` starts
> failing
>
>   http://git.haskell.org/ghc.git/commitdiff/6f46fe15af397d448438c6b93babcdd68dd78df8
>
> ...which sadly is a rather large patch :-/