We've got a Perl script, it's reliably giving us a Segfault. I put debug in, and presto! Problem solved. Put it in the debugger? Works fine.

We've narrowed down the problem as follows. Our code:

...
eval { $DT = DateTime->new( year => $year, time_zone => $tz ); };
return if $@;
...
[download]

Specifically, the above code executes normally several dozen times, and then segfaults when passed a $year of "2011", and a $tz of "Europe/London". BUT! Here's the catch, and here's where I'm getting out of my league:

JUST before that, it calls the same code with $year = "2010" and $tz = "Europe/London". THAT call fails and is successfully caught by the wrapped eval, which actually returns us an error message like this:

The 'name' parameter (undef) to DateTime::TimeZone::new was an 'undef'
+, which is not one of the allowed types: scalar
 at /idcom/weblive/extperl/lib/perl5/site_perl/5.8.5/DateTime/TimeZone
+.pm line 34
        DateTime::TimeZone::new('undef', 'name', 'undef') called at
/idcom/weblive/extperl/lib64/perl5/site_perl/5.8.5/x86_64-linux-thread
+-multi/DateTime.pm line 192
        DateTime::new('undef', 'year', 2010, 'time_zone', 'Europe/Lond
+on') called at TZInfo.pm line 33
        TZInfo::get_dst_changes(2010, 'Europe/London') called at ./nz.
+pl line 1039
[download]

The NEXT call (for 2011, same time zone), causes the segfault, and isn't caught by the wrapped eval.

So. One thing I noticed is that it reports that I called both DateTime::new and DateTime::TimeZone::new with a leading "undef" parameter! Shouldn't that be the package name?

Beyond that, I'm at a loss. I can't replicate it in a smaller, standalone test, and I have no idea why it should actually segfault. And looking at DateTime::new, it looks like it's possible that the Params::Validate module is what's processing the arguments and turning the name field into an undef-- but it seems wholly unlikely to me that there would be a bug in either DateTime, DateTime::TimeZone, or Params::Validate.

Any ideas?

DaveE

UPDATE

Well, not much to say apart from the fact that I've quasi-confirmed that Params::Validate isn't doing what it's supposed to do (probably thanks to some error state that we've created, but I have no idea how). Within DateTime.pm:

...
sub new
{
    my $class = shift;
    my %p = validate( @_, $NewValidate );
...
[download]

I added in debug (that still contained the failure) to print out @_, %p, and $NewValidate both before and after the call to Params::Validate. Result?

@_ set to:
$VAR1 = [
          'year',
          2010,
          'time_zone',
          'Europe/London'
        ];
%p set to:
$VAR1 = {};
[download]

So, it properly shifted off the $class (it was being set correctly it seems), but when attempting to pass off to Params::Validate::validate, the resultant hash comes back empty! Trying to hack into Params::Validate now, but I have a feeling I'm barking up the wrong tree-- maybe something's screwed up the stack and comes unstuck at the return from Params::Validate or something, but again, I have doubts that the library itself has a problem.

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