[PATCH 5.6.0] fix for 'FATAL all' (was RE: lexical warnings bug? )

From: paul.marquess@bt.com [mailto:paul.marquess@bt.com]
 
> From: Tom Christiansen [mailto:tchrist@chthon.perl.com]
>  
> > >Could you give an example of the usage of the code that illustrates the
> > >problem please Tom.
> > 
> > Right, sorry.  It was snipped from yesterday's pathedit program.
> > 
> >     #!/usr/bin/perl 
> > 
> >     use warnings;
> >     no warnings 'redefine';
> > 
> >     use Carp;
> > 
> >     my @names = qw(/tmp/foo /tmp/bar);
> >     my $code = q{$a + $b};
> > 
> >     print "Trying compile with fatal warnings\n\n";
> >     eval { 
> > 	compile1($code);
> > 	pathedit() for @names;
> >     };
> >     warn if $@;
> > 
> >     print "\nTrying compile with sigwarn\n\n";
> >     eval { 
> > 	compile2($code);
> > 	pathedit() for @names;
> >     };
> >     warn if $@;
> > 
> >     sub compile1 {
> >        my $op    = shift;
> >        *pathedit = eval qq{
> > 	   sub () { 
> > 	       use warnings qw/FATAL all/;  # XXX: does not work
> > 	       $op;
> > 	   }   
> >        } || do {
> > 	   local $_ = $@;
> > 	   s/at \(eval.*//s;
> > 	   die "$0: can't compile perlexpr $op: $_\n";
> >        } 
> >     } 
> > 
> >     sub compile2 {
> >        my $op    = shift;
> >        *pathedit = eval qq{
> > 	   sub () { 
> > 	       local \$SIG{__WARN__} = sub { 
> > 		   local \$_ = "\@_";
> > 		   s/at \\(eval.*//;
> > 		   confess "FATAL WARNING: \$_";
> > 	       };
> > 	       $op;
> > 	   }   
> >        } || do {
> > 	   local $_ = $@;
> > 	   s/at \(eval.*//s;
> > 	   die "$0: can't compile perlexpr $op: $_\n";
> >        } 
> >     } 
> > 
> > That produces this:
> > 
> >     Trying compile with fatal warnings
> > 
> >     Use of uninitialized value in addition (+) at (eval 1) line 4.
> >     Use of uninitialized value in addition (+) at (eval 1) line 4.
> >     Use of uninitialized value in addition (+) at (eval 1) line 4.
> >     Use of uninitialized value in addition (+) at (eval 1) line 4.
> > 
> >     Trying compile with sigwarn
> > 
> >     FATAL WARNING: Use of uninitialized value in addition (+) 
> > 	    main::__ANON__('Use of uninitialized value in addition (+) at
> (eval 2) line 8.^J') called at (eval 2) line 8
> > 	    main::__ANON__() called at /tmp/p line 21
> > 	    require 0 called at /tmp/p line 19
> > 	    ...caught at /tmp/p line 23.
> > 
> > The question is: shouldn't the fatal warnings version also be, well,
> fatal?
> 
> Indeed they should. The logic that processes "FATAL all" is broken. Expect
a
> patch in the next couple of days.

Here is a patch to fix the bug. Although it can apply over a fresh 5.6.0, it
should really be applied along with the last eval+warnings patch both
Sarathy and I posted.

Paul

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`
end

• [PATCH 5.6.0] fix for 'FATAL all' (was RE: lexical warnings bug? ) by paul.marquess