Re: [Grep-devel] [platform-testers] new snapshot available: grep-2.25.101-be82

[Assaf Gordon]

Hello Paul and all,

On 09/27/2016 11:59 AM, Paul Eggert wrote:
> On 09/27/2016 08:09 AM, Jim Meyering wrote:
> > Would you please adjust it not to use
> > configure's--enable-gcc-warnings option?
>
> He didn't use the --enable-gcc-warnings option; warnings were enabled
> automatically because he built from a Git checkout[...] I installed the 
> attached patch to try
> to fend off reports like this in the future.

Few minor thoughts/questions regarding this patch:
(I assume similar patches will propagate to other projects as well)

1.
gcc-6.2 is rather new (released about a month ago).

Would it be possible to consider some older GCC's as still valid
for automatically enabling warnings ?

These are the versions for some stable versions distributions:
  CentOS 7:     gcc 4.8
  Ubuntu 16.04: gcc 5.4
  Debian 8:     gcc 4.9
  fedora 23:    gcc 5.1
  fedora 24:    gcc 6.1

Effectively this means that developers using stable distributions will
need to build and install a new compiler, or forgo the warnings (which are very 
useful).


2.
This check will disable warnings when not using GCC (e.g. clang).
Of course clnag brings its own host of warning-related issues,
but with this patch warnings will never be automatically enabled for clang 
developers when using git.


3.
The code that is generated with 'AC_LANG_PROGRAM' during './configure' is this:
===
         #if 6 < __GNUC__ + (2 <= __GNUC_MINOR__)
             int main (void) { return 0; }
          #else
            #error "This GCC is too old."
          #endif
 
int
main ()
{

  ;
  return 0;
}
===

which means there are two 'main()' - not sure if this compiles successfully or 
not
(compiling manually seems to fail).


4.
If we decide to keep this as-is, perhaps it would be helpful to rephrase the 
error message
to 'Enabling warnings requires GCC=>6.2' ?

because if there's some digging in the logs for troubleshooting,
it will be clear that the error only refers to auto-enabling warnings,
and not that "this GCC is too old" for building the program?
(also in case this is not GCC at all).



regards,
 - assaf