Re: [PATCH] grep: Don't pass a TODO test if REG_STARTEND is supported

> On Thu, Jul 15, 2010 at 17:47, Junio C Hamano <gitster@pobox.com> wrote:
>> Ævar Arnfjörð Bjarmason <avarab@gmail.com> writes:
>>
>>> On Thu, Jul 8, 2010 at 19:40, Junio C Hamano <gitster@pobox.com> wrote:
>>>> Ævar Arnfjörð Bjarmason  <avarab@gmail.com> writes:
>>>>
>>>>> +if git grep ile a
>>>>> +then
>>>>> +     test_expect_success 'git grep ile a' 'git grep ile a'
>>>>> +else
>>>>> +     test_expect_failure 'git grep ile a' 'git grep ile a'
>>>>> +fi
>>>>
>>>> So if command "X" is known to succeed, we run it inside expect_success
>>>> and if not we run it inside expect_failure?
>>>>
>>>> What kind of idiocy is that, I have to wonder...
>>>
>>> Well, the point is to normalize the test suite so that we never have
>>> passing TODO tests if everything's OK.
>>
>> I do not consider a test that passes under some condition but doesn't
>> under some other condition "everything is OK".  Marking the test as
>> "expect failure" as René originally did makes a lot of sense to me.
>>
>> The quoted patch is even worse as it will _actively_ prevent you from
>> catching a new error you just introduced while futzing "git grep" on a
>> platform that used to work.  Your "if" statement will say "ah, grep is
>> broken", and you will use expect-failure, not because your platform does
>> not support REG_STARTEND, but because you broke "git grep".
>>
>> The point of having tests is to help you catch your bugs while you
>> develop.  A test that turns itself off when the feature it is testing is
>> broken helps nobody.
>>
>> So forget about "passing TODO tests", whatever a "TODO test" is.  The
>> change in question is actively _wrong_.
>
> I was under the impression that REG_STARTEND was considered purely
> icing on the cake, i.e. that the tests should be passing whether or
> not it was present.
>
> I guess my reasoning at the time was that if that wasn't the case,
> reporting an unexpected pass by default, as opposed to a failing TODO
> on platforms without REG_STARTEND. Since only TAP will report this, I
> thought that was just an omission.
>
> Anyway, since REG_STARTEND *isn't* obviously considered icing you're
> of course right, but the test is still broken as-is. Now it reports an
> abnormal condition if REG_STARTEND is present (passing TODO test), it
> should instead have a failing TODO test where REG_STARTEND isn't
> present. I'll come up with a patch to fix that.

> We should also just upgrade the GNU regex library in compat/regex to
> the version that supports REG_STARTEND. Unfortunately that seems
> easier said than done, since the library is now part of glibc, and has
> aquired a lot of glibc specific macros and other constructs that would
> need to be #defined away or otherwise worked around.