I succeeded in generating this error with a pure perl program (v5.10.1 (*) built for i686-cygwin-thread-multi-64int) with the following code:
#!/usr/bin/perl -w
use strict;
use Data::Dumper;
$Data::Dumper::Indent = 1;
my $hashref;
for my $i0 (1..2) {
for my $i1 (1..2) {
for my $i2 (1..2) {
$hashref->{"$i0"}{"$i0:$i1"}{"$i0:$i1:$i2"} = "$i0:$i1:$i2";
}
}
}
deletehashlevel($hashref, 1);
print Dumper($hashref);
exit;
sub athashleveldo {
my ($h, $n, $action) = @_;
if ($n==0) {
$action->($h);
} else {
athashleveldo($_, $n-1, $action) for values %$h;
}
}
sub deletehashlevel {
my ($h, $n) = @_;
athashleveldo($h, $n, sub {
my %tmp;
for my $key (keys %$h) {
my $val = delete $h->{$key};
@tmp{keys %$val} = values %$val;
}
%$h = %tmp;
});
}
__END__
Running this program:
$ ./testhashdel
Use of freed value in iteration at ./testhashdel line 27.
The error goes away when I apply the same solution as js1 did, replacing:
athashleveldo($_, $n-1, $action) for values %$h;
with
my @v = values %$h;
athashleveldo($_, $n-1, $action) for @v;
Is this a bug in Perl, lurking to bite me at some later time?
