Re: [PATCH] travis-ci: run scan-build every time

[Samuel Lijin <sxlijin@gmail.com>]

On Sun, Feb 26, 2017 at 8:12 AM, Lars Schneider
<larsxschneider@gmail.com> wrote:
>
>> On 26 Feb 2017, at 03:09, Samuel Lijin <sxlijin@gmail.com> wrote:
>>
>> On Sat, Feb 25, 2017 at 3:48 PM, Lars Schneider
>> <larsxschneider@gmail.com> wrote:
>>>
>>>> On 24 Feb 2017, at 18:29, Samuel Lijin <sxlijin@gmail.com> wrote:
>>>>
>>>> It's worth noting that there seems to be a weird issue with scan-build
>>>> where it *will* generate a report for something locally, but won't do it
>>>> on Travis. See [2] for an example where I have a C program with a
>>>> very obvious memory leak but scan-build on Travis doesn't generate
>>>> a report (despite complaining about it in stdout), even though it does
>>>> on my local machine.
>>>>
>>>> [1] https://travis-ci.org/sxlijin/git/builds/204853233
>>>> [2] https://travis-ci.org/sxlijin/travis-testing/jobs/205025319#L331-L342
>>>
>>> Scan-build stores the report in some temp folder. I assume you can't access
>>> this folder on TravisCI. Try the scan-build option "-o scan-build-results"
>>> to store the report in the local directory.
>>
>> That occurred to me, but I don't quite think that's the issue. I just
>> noticed that on the repo I use to test build matrices, jobs 1-8 don't
>> generate a report, but 9-14 and 19-20 do [1]. I don't think it's an
>> issue with write permissions (scan-build complains much more vocally
>> if that happens), but it doesn't seem to matter if the output dir is
>> in the tmpfs [2] or a local directory [3].
>>
>> [1] https://travis-ci.org/sxlijin/travis-testing/builds/205054253
>> [2] https://travis-ci.org/sxlijin/git/jobs/205028920#L1000
>> [2] https://travis-ci.org/sxlijin/git/jobs/205411705#L998
>
> Scan-build somehow replaces the compiler. My guess is that you
> tell scan-build to substitute clang but "make" is really using
> gcc or something?

Your hunch is spot-on. I took a look at the Makefile and lo and
behold, it overrides $CC [1]. Looking at the commit which introduced
it [2] I have to admit I'm somewhat surprised that scan-build works at
all...

[1] https://github.com/git/git/blob/master/Makefile#L454
[2] https://github.com/git/git/commit/6d62c983f7d91565a15e49955b3ed94ae7c73434

> I reported something strange about the compilers
> on TravisCI some time ago but I can't find it anymore. I think I
> remember on OSX they always use clang even if you define gcc.
> Maybe it makes sense to reach out to TravisCI support in case
> this is a bug on their end?
>
> Based on your work I tried the following and it seems to work:
> https://travis-ci.org/larsxschneider/git/jobs/205507241
> https://github.com/larsxschneider/git/commit/faf4ecfdca1a732459c1f93c334928ee2826d490

That's promising!

> - Lars