Re: [git-for-windows] Re: Continuous Testing of Git on Windows

["Philip Oakley" <philipoakley@iee.org>]

From: "Christian Couder" <christian.couder@gmail.com>
> On Tue, Feb 14, 2017 at 10:08 PM, Junio C Hamano <gitster@pobox.com> 
> wrote:
>> Johannes Schindelin <Johannes.Schindelin@gmx.de> writes:
>>
>>> On Mon, 13 Feb 2017, Junio C Hamano wrote:
>>>
>>>> Johannes Schindelin <Johannes.Schindelin@gmx.de> writes:
>>>>
>>>> > That is why I taught the Git for Windows CI job that tests the four
>>>> > upstream Git integration branches to *also* bisect test breakages and
>>>> > then upload comments to the identified commit on GitHub
>>>>
>>>> Good.  I do not think it is useful to try 'pu' as an aggregate and
>>>> expect it to always build and work [*1*], but your "bisect and
>>>> pinpoint" approach makes it useful to identify individual topic that
>>>> brings in a breakage.
>>>
>>> Sadly the many different merge bases[*1*] between `next` and `pu` (which
>>> are the obvious good/bad points for bisecting automatically) bring my
>>> build agents to its knees. I may have to disable the bisecting feature 
>>> as
>>> a consequence.
>
> Yeah, this is a bug in the bisect algorithm. Fixing it is in the GSoC
> 2017 Ideas.

There are also a few ideas at the SO answers: 
http://stackoverflow.com/a/5652323/717355

>
>> Probably a less resource intensive approach is to find the tips of
>> the topics not in 'next' but in 'pu' and test them.  That would give
>> you which topic(s) are problematic, which is a better starting point
>> than "Oh, 'pu' does not build".  After identifying which branch is
>> problematic, bisection of individual topic would be of more manageable
>> size.
>
> It is still probably more resource intensive than it couls be.
>
> [...]
>
>> This is one of these times I wish "git bisect --first-parent" were
>> available.
>
> Implementing "git bisect --first-parent" is also part of the GSoC 2017 
> Ideas.
>
> By the way it should not be very difficult as a patch to do this and
> more was proposed a long time ago:
>
> https://public-inbox.org/git/4D3CDDF9.6080405@intel.com/
>
>> The above "log" gives me 27 merges right now, which
>> should be bisectable within 5 rounds to identify a single broken
>> topic (if there is only one breakage, that is).
>
--
Philip