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xt/poll_cb_destroy_during_call.t  view on Meta::CPAN

#
# After every callback return poll_cb must REEXTRACT_SUB and croak
# "... object destroyed during the call" / "... object was replaced during
# the call" instead of dereferencing the freed pointer.  Without the guard
# the next loop iteration reads/writes freed heap: it either segfaults
# (caught as a signal below) or, if the freed memory is still mapped,
# silently runs on through it and poll_cb returns normally (exit 7 below).
# Both are failures; only the specific croak is a pass.
#
# Each child publishes 3 messages and destroys/replaces on the FIRST
# callback, so the defect window (second and later loop iterations) is
# always exercised.  alarm is a backstop against a garbage-cursor spin in
# the unfixed code.

my @cases;

for my $variant (qw(Int Str Int32 Int16)) {
    push @cases, ["Data::PubSub::Shared::${variant}::Sub (destroy in callback)" => sub {
        my $ps = "Data::PubSub::Shared::$variant"->new(undef, 32);
        $ps->publish($variant eq 'Str' ? "msg$_" : $_) for 1..3;
        my $sub = $ps->subscribe_all;