Re: [PATCH] xen/Makefile: drop -Werror

[Fabrice Fontaine <fontaine.fabrice@xxxxxxxxx>]

Le ven. 2 juil. 2021 à 19:34, Andrew Cooper
<andrew.cooper3@xxxxxxxxxx> a écrit :
>
> On 02/07/2021 18:06, Fabrice Fontaine wrote:
> > Drop -Werror to avoid the following build failure with -DNDEBUG:
> >
> > In file included from <command-line>:0:0:
> > /usr/lfs/hdd_v1/rc-buildroot-test/scripts/instance-0/output-1/build/xen-4.14.2/xen/include/xen/config.h:94:0:
> >  error: "NDEBUG" redefined [-Werror]
> >  #define NDEBUG
> >
> > <command-line>:0:0: note: this is the location of the previous definition
> >
> > Fixes:
> >  - 
> > http://autobuild.buildroot.org/results/66573ad0abc4244c0dfeac8b684a7bfcc31c0d4d
> >
> > Signed-off-by: Fabrice Fontaine <fontaine.fabrice@xxxxxxxxx>
>
> For better or worse, It is Xen's policy that -Werror will remain.  95%
> of the time, it is the right thing.  We will however build failures
> whenever they crop up.
>
> This one is weird though.  How is NDEBUG getting in twice?  What does
> the rest of this build environment look like?
NDEBUG is added by buildroot in the command line if the user sets
BR2_ENABLE_RUNTIME_DEBUG to false since
https://git.buildroot.net/buildroot/commit/?id=5a8c50fe05afacc3cbe8e7347e238da9f242fab0

I do agree that setting -Werror is generally perfectly valid for upstream.
However, for downstream packager, it is generally seen as an issue as
it will always raise unexepected build failures with older, newer, or
exotic toolchains, see
https://embeddedartistry.com/blog/2017/05/22/werror-is-not-your-friend.
It would be good to, at least, have an option to disable -Werror for
example through a XEN_DISABLE_WERROR.
>
> ~Andrew
Best Regards,

Fabrice