[vlc-devel] [PATCH 1/2] configure: add an option to turn some dangerous warnings into errors

[Steve Lhomme]

On 2020-03-20 10:29, Rémi Denis-Courmont wrote:
> Le perjantaina 20. maaliskuuta 2020, 11.20.49 EET Steve Lhomme a écrit :
>> Mismatching pointers are usually a result of using the incorrect pointer and
>> might trigger crashes.
>>
>> Missing initializers are useful for structures of callbacks, to make sure a
>> new callback is not missing by accident. It's always possible to put NULL,
>> on purpose, knowingly.
>>
>> Both flags produce no error on win32/win64 with clang or gcc. But they
>> cannot be set globally outside of the build script as many contribs will
>> likely fail these tests and we shouldn't refuse/patch a contrib just for
>> that.
>>
>> I have been compiling with these flags for weeks without issues. It helped
>> find some issue (48442d3536edae578f1a384e73346d1e2a4c0061) that were pushed
>> unnoticed without these checks.
>> ---
>>   configure.ac | 6 ++++++
>>   1 file changed, 6 insertions(+)
>>
>> diff --git a/configure.ac b/configure.ac
>> index bc1874cb97c..c96b3fe6fac 100644
>> --- a/configure.ac
>> +++ b/configure.ac
>> @@ -4480,6 +4480,12 @@ AS_VAR_IF(with_libfuzzer, no, [], [
>>       ])
>>   ])
>>
>> +AC_ARG_ENABLE([extra-checks],
>> +  AS_HELP_STRING([--enable-extra-checks],
>> +         [Turn some compilation warnings into errors]), [
>> +  AX_APPEND_COMPILE_FLAGS([-Werror=incompatible-pointer-types
>> -Werror=missing-field-initializers], [CFLAGS]) +])
> 
> I don't see what justifies adding yet another option here. In this case, you
> can just as well pass them with CFLAGS/CXXFLAGS like everybody and everything
> else does.

No you can't. If you do that before running one of the build scripts, 
they apply to contribs as well.