From: Chris Packham <judge.packham@gmail.com>
To: Jeff King <peff@peff.net>
Cc: GIT <git@vger.kernel.org>, Elia Pinto <gitter.spiros@gmail.com>
Subject: Re: [RFC/PATCH] Makefile: add cppcheck target
Date: Wed, 14 Dec 2016 21:33:59 +1300 [thread overview]
Message-ID: <CAFOYHZBRq=5FGswQZSYbn0JdrEv+xqLm6gdpD_nE+1L_CfPHEw@mail.gmail.com> (raw)
In-Reply-To: <20161213121510.5o5axuwzztbxcvfd@sigill.intra.peff.net>
On Wed, Dec 14, 2016 at 1:15 AM, Jeff King <peff@peff.net> wrote:
> On Tue, Dec 13, 2016 at 10:22:25PM +1300, Chris Packham wrote:
>
>> $ make cppcheck
>> cppcheck --force --quiet --inline-suppr .
>> [compat/nedmalloc/malloc.c.h:4093]: (error) Possible null pointer dereference: sp
>> [compat/nedmalloc/malloc.c.h:4106]: (error) Possible null pointer dereference: sp
>> [compat/nedmalloc/nedmalloc.c:551]: (error) Expression '*(&p.mycache)=TlsAlloc(),TLS_OUT_OF_INDEXES==*(&p.mycache)' depends on order of evaluation of side effects
>> [compat/regex/regcomp.c:3086]: (error) Memory leak: sbcset
>> [compat/regex/regcomp.c:3634]: (error) Memory leak: sbcset
>> [compat/regex/regcomp.c:3086]: (error) Memory leak: mbcset
>> [compat/regex/regcomp.c:3634]: (error) Memory leak: mbcset
>> [compat/regex/regcomp.c:2802]: (error) Uninitialized variable: table_size
>> [compat/regex/regcomp.c:2805]: (error) Uninitialized variable: table_size
>> [compat/regex/regcomp.c:532]: (error) Memory leak: fastmap
>> [t/t4051/appended1.c:3]: (error) Invalid number of character '{' when these macros are defined: ''.
>> [t/t4051/appended2.c:35]: (error) Invalid number of character '{' when these macros are defined: ''.
>>
>> The last 2 are just false positives from test data. I haven't looked
>> into any of the others.
>
> I think these last two are a good sign that we need to be feeding the
> list of source files to cppcheck. I tried your patch and it also started
> looking in t/perf/build, which are old versions of git built to serve
> the performance-testing suite.
>
> See the way that the "tags" target is handled for a possible approach.
>
> My main complaint with any static checker is how we can handle false
> positives. I think our use of "-Wall -Werror" is successful because it's
> not too hard to keep the normal state to zero warnings. Looking at the
> output of cppcheck on my system (which is different than on yours!),
I think you get a similar class of problems with different compilers
(different gcc versions, clang, msvc). Although this appears to be
mitigated already with the diverse developers in the git community.
> I do see a few real problems, but many false positives, too.
> Unfortunately, one of the false positives is:
>
> int foo = foo;
On I side note I have often wondered how this actually works to avoid
the uninitialised-ness of foo. I can see how some compilers may be
fooled into thinking that foo has been set but that doesn't actually
end up with foo having a deterministic value.
> to silence -Wuninitialized, which causes cppcheck to complain that "foo"
> is uninitialized. I'm worried we will end up with two static checkers
> fighting each other, and no good way to please both.
>
> -Peff
next prev parent reply other threads:[~2016-12-14 8:34 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-12-13 9:22 [RFC/PATCH] Makefile: add cppcheck target Chris Packham
2016-12-13 9:32 ` Chris Packham
2016-12-13 9:37 ` stefan.naewe
2016-12-13 12:15 ` Jeff King
2016-12-13 12:28 ` Jeff King
2016-12-14 8:23 ` Chris Packham
2016-12-14 8:33 ` Chris Packham [this message]
2016-12-14 11:18 ` Jeff King
2016-12-14 9:27 ` [RFC/PATCHv2] " Chris Packham
2016-12-14 11:24 ` Jeff King
2016-12-14 14:46 ` Jeff King
2016-12-15 23:22 ` [RFC/PATCH] Makefile: suppress some cppcheck false-positives Chris Packham
2016-12-16 18:43 ` Junio C Hamano
2016-12-16 22:16 ` Jeff King
[not found] ` <6ABA4AA4-BD5C-4178-BB3B-91CA045EA2AD@gmail.com>
2016-12-17 7:31 ` [RFC/PATCHv2] Makefile: add cppcheck target Chris Packham
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