Hi morgon,

Based on your example code, would it be correct to assume that the problem is happening because of circular references? If so, then tracking those down might be a good start, it should lead you to the culprit code.

I looked into tracking circular references, unfortunately it seems that Devel::LeakTrace and Devel::LeakTrace::Fast don't compile on modern versions of Perl/glib, Devel::Leak seems a bit too low-level, and Devel::Cycle requires you to specify which variables to check for cycles, which can be difficult if you have lots of objects being created. So far, the "best" thing I have found seems to be Devel::Leak::Object, which can override bless.

Also, I fiddled around with Devel::Gladiator and has_circular_ref from Data::Structure::Util, which seems to support more types of data than Devel::Cycle. Note that it appears to be important to limit the inspection to those things that we're actually interested in, in this case objects - just blindly using it on everything that walk_arena() returns leads to errors, and I even got some segfaults at one point. But the following seems to work, at least on your example code:

use Devel::Gladiator qw/walk_arena/;
use Data::Structure::Util qw/has_circular_ref/;
use Scalar::Util qw/blessed/;
sub find_all_cycles {
    my $all = walk_arena();
    for my $sv (@$all) {
        # limit search to objects
        next unless blessed($sv);
        warn "Has circular references: $sv\n"
            if has_circular_ref($sv);
    }
    @$all=();
}
END { find_all_cycles() }

[download]

Hope this helps,
-- Hauke D

In reply to Re: is there a way to ensure some code is the last thing that is run? by haukex
in thread is there a way to ensure some code is the last thing that is run? by morgon

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