Re: Undefined value returned on call to readline (<>)?

[Anonymous Monk]

FYI, the author isn't interested in fixing it: https://rt.cpan.org/Public/Bug/Display.html?id=108434

[choroba]

The fix presented in the bug report is not nice. It uses the my $var if ..., discussed for example in Conditional initialization of my-variables.

It would've been cleaner to use something like

                || die qq/Cannot open pid file "$self->{path}": $!\n/;
        flock($fh, LOCK_EX | LOCK_NB)
         || die qq/pid "$self->{path}" already locked: $!\n/;
-       my ($pid) = <$fh> =~ /^(\d+)/;
+       my $maybe = <$fh>;
+       $maybe = "" unless defined $maybe;
+       my ($pid) = $maybe =~ /^(\d+)/;
        close $fh if @_ == 1;

[Intrepid]

"It would've been cleaner to use something like"
...


I happily accept your patch, choroba - if only I was the module author. And I read the bug thread over at Debian and I am in agreement that it was not nice.

This was interesting, educational for me, points for choroba and ikegami. The reply from ikegami confirmed what I suspected, and the discussion at Conditional initialization of my-variables was enlightening. I had looked at that code in Proc-PID-File and it bothered me with out me knowing exactly why. I guess I have some good Perl instincts after all; sometimes we code too compactly, saving a couple more lines of code but introducing a problem in doing so. Yes, indeed, Perl lends itself to obfuscation.

Feb 18, 2025 at 19:51 UTC