I'm testing a mod_perl application and seeing intermittent segfaults. I've traced at least one of these to a method that looks rather like this: 
sub getWorkspace {
    my ($self, $WHERE, $TYPE) = @_;
    $TYPE = $self->getType($TYPE) if ($TYPE);

    sub cmpval {
        my ($val1, $val2) = @_;

        if (ref($val1) eq 'Node') { $val1 = $$val1{node_id}; };
        if (ref($val2) eq 'Node') { $val2 = $$val2{node_id}; }
    
        $val1 eq $val2;
    }
    
    foreach my $node (keys %{ $this->{workspace}{nodes} }) {
        my $N = $this->getNode($node);

        my $match = 1;
        foreach (keys %$WHERE) {
            $match = 0 unless cmpval($$N{$_}, $$WHERE{$_});
        }
        push @results, $N if $match;
    }
    return \@results;
}

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Now mod_perl uses eval() tricks to compile the whole application into a handler subroutine, so all of the top-level sub declarations will be at least one level lower.

My question is, am I right to be suspicious of the inner subroutine (cmpval())? Is there a limit as to how far you can nest these things before you run into a stack limit?

It's easy enough to move the inner sub outside, or create an anonymous sub out of it. Can anyone confirm my suspicions?

In reply to Inner Subroutines, mod_perl, and Segfaults by chromatic

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