[FFmpeg-devel] [PATCH V3 3/5] libavformat/protocols.c: fix build warning for [-Wdiscarded-qualifiers]

[Guo, Yejun]

> -----Original Message-----
> From: ffmpeg-devel <ffmpeg-devel-bounces at ffmpeg.org> On Behalf Of Reimar
> D?ffinger
> Sent: 2021年2月27日 22:09
> To: FFmpeg development discussions and patches <ffmpeg-devel at ffmpeg.org>
> Subject: Re: [FFmpeg-devel] [PATCH V3 3/5] libavformat/protocols.c: fix build
> warning for [-Wdiscarded-qualifiers]
> 
> 
> 
> > On 27 Feb 2021, at 09:14, Guo, Yejun <yejun.guo at intel.com> wrote:
> >
> >
> >
> >> -----Original Message-----
> >> From: ffmpeg-devel <ffmpeg-devel-bounces at ffmpeg.org> On Behalf Of
> >> Paul B Mahol
> >> Sent: 2021年2月26日 19:37
> >> To: FFmpeg development discussions and patches
> >> <ffmpeg-devel at ffmpeg.org>
> >> Cc: Guo, Yejun <yejun.guo at intel.com>
> >> Subject: Re: [FFmpeg-devel] [PATCH V3 3/5] libavformat/protocols.c:
> >> fix build warning for [-Wdiscarded-qualifiers]
> >>
> >> look at same/similar patches like yours that have been already rejected.
> >
> > thanks for the info.
> >
> > My motivation to fix the build warnings is that: I have several
> > patches caught by patchwork with build warnings that I missed. I'd
> > like to avoid it. And the best method, IMO, is to add '-Wall -Werror' for the
> build option.
> 
> I think that is a bad idea, compilers add new warnings all the time, many of
> them unreliable or of questionable quality/usefulness.
> What you end up with using -Werror is a project that constantly fails to build
> and gets a reputation for low quality.
> However there may well be specific, reliable warning types for which we
> should add an error specifically, as we already do now for e.g.
> -Werror=implicit-function-declaration
> There might also be other options to improve things and ensure relevant
> warnings are visible and addressed, but I’ve yet to see a -Werror have
> convincing effects (for example one effect it usually has is that people have to
> stick to “supported” compiler versions to avoid constant issues with build
> failures, reducing testing and actually decreasing code quality instead of
> increasing it).
> Turning it around, using -Werror successfully would mean testing with all
> compiler versions regularly including pre-release versions and ensuring any
> issues are fixed immediately. Which I don’t think is an approach that would
> work for FFmpeg.
> 
> > Such option can also help to find
> > potential issues in the code. This is the reason that I plan to fix
> > the build warnings one by one together with community.
> 
> I believe many are likely to be fixable in a way that most developers would be
> quite happy with, even consider it an improvement beyond just the
> warning/bug fix.
> It’ll just take a lot more effort to find those types of fixes.
> After all if it was that simple there could just be an option for the compiler to
> fix them itself, the reason there isn’t is because it would likely end very badly.
> 
> Best regards,
> Reimar

thanks for your nice explanation, thank you.