Re: [PATCH 1/2] [pr53679] libgo: add a --enable-werror configure flag

[Mike Frysinger <vapier at gentoo dot org>]

On Tuesday 15 January 2013 09:56:06 Ian Lance Taylor wrote:
> On Sun, Dec 23, 2012 at 3:30 PM, Mike Frysinger <vapier@gentoo.org> wrote:
> > diff --git a/libgo/configure.ac b/libgo/configure.ac
> > index 8cde50b..63d8cbc 100644
> > --- a/libgo/configure.ac
> > +++ b/libgo/configure.ac
> > @@ -50,8 +50,11 @@ AC_PROG_AWK
> > 
> >  WARN_FLAGS='-Wall -Wextra -Wwrite-strings -Wcast-qual'
> >  AC_SUBST(WARN_FLAGS)
> > 
> > -dnl FIXME: This should be controlled by --enable-maintainer-mode.
> > -WERROR="-Werror"
> > +AC_ARG_ENABLE(werror, [AS_HELP_STRING([--enable-werror],
> > +                                      [turns on -Werror
> > @<:@default=yes@:>@])]) +if test "x$enable_werror" != "xno"; then
> > +  WERROR="-Werror"
> > +fi
> > 
> >  AC_SUBST(WERROR)
> >  
> >  glibgo_toolexecdir=no
> 
> Can you say something about when you needed this?  What errors were you
> seeing?

the referenced PR describes one:
/build/src/gcc-4.7.1/libgo/runtime/print.c: In function 'gwrite':
/build/src/gcc-4.7.1/libgo/runtime/print.c:20:3: error: ignoring return value
of 'write', declared with attribute warn_unused_result [-Werror=unused-result]
cc1: all warnings being treated as errors

this bites distros that enable security settings by default (such as fortify 
and ssp).  but ignoring even that, i don't believe releases should build all 
the time with -Werror -- i'm fine with defaulting to on as long as there is a 
configure flag to turn it off which is what this does like is already handled in 
much of the sourceware tree.  -Werror is great for development, but sucks when 
deployed on actual systems.  the assumptions made at time of checkin rarely 
stay constant forever (in this case, a changing lib C can easily break it).
-mike

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