Re: Make all Perl warnings fatal

To avoid a complete bloodbath on cfbot, here is an updated patch set 
that includes a workaround for the getprotobyname() issue mentioned below.


On 10.08.23 07:58, Peter Eisentraut wrote:
> We have a lot of Perl scripts in the tree, mostly code generation and 
> TAP tests.  Occasionally, these scripts produce warnings.  These are 
> AFAICT always mistakes on the developer side (true positives).  Typical 
> examples are warnings from genbki.pl or related when you make a mess in 
> the catalog files during development, or warnings from tests when they 
> massage a config file that looks different on different hosts, or 
> mistakes during merges (e.g., duplicate subroutine definitions), or just 
> mistakes that weren't noticed, because, you know, there is a lot of 
> output in a verbose build.
> 
> I wanted to figure put if we can catch these more reliably, in the style 
> of -Werror.  AFAICT, there is no way to automatically turn all warnings 
> into fatal errors.  But there is a way to do it per script, by replacing
> 
>      use warnings;
> 
> by
> 
>      use warnings FATAL => 'all';
> 
> See attached patch to try it out.
> 
> The documentation at <https://perldoc.perl.org/warnings#Fatal-Warnings> 
> appears to sort of hand-wave against doing that.  Their argument appears 
> to be something like, the modules you use might in the future produce 
> additional warnings, thus breaking your scripts.  On balance, I'd take 
> that risk, if it means I would notice the warnings in a more timely and 
> robust way.  But that's just me at a moment in time.
> 
> Thoughts?
> 
> 
> Now to some funny business.  If you apply this patch, the Cirrus CI 
> Linux tasks will fail, because they get an undefined return from 
> getprotobyname() in PostgreSQL/Test/Cluster.pm.  Huh?  I need this patch 
> to get past that:
> 
> diff --git a/src/test/perl/PostgreSQL/Test/Cluster.pm 
> b/src/test/perl/PostgreSQL/Test/Cluster.pm
> index 3fa679ff97..dfe7bc7b1a 100644
> --- a/src/test/perl/PostgreSQL/Test/Cluster.pm
> +++ b/src/test/perl/PostgreSQL/Test/Cluster.pm
> @@ -1570,7 +1570,7 @@ sub can_bind
>      my ($host, $port) = @_;
>      my $iaddr = inet_aton($host);
>      my $paddr = sockaddr_in($port, $iaddr);
> -   my $proto = getprotobyname("tcp");
> +   my $proto = getprotobyname("tcp") || 6;
> 
>      socket(SOCK, PF_INET, SOCK_STREAM, $proto)
>        or die "socket failed: $!";
> 
> What is going on there?  Does this host not have /etc/protocols, or 
> something like that?
> 
> 
> There are also a couple of issues in the MSVC legacy build system that 
> would need to be tightened up in order to survive with fatal Perl 
> warnings.  Obviously, there is a question whether it's worth spending 
> any time on that anymore.