jkeenan
commented
1 year ago I suspect this ticket should get the "my-in-false-conditional" label. Can someone confirm that?
Open Azq2 opened 1 year ago
jkeenan
commented
1 year ago I suspect this ticket should get the "my-in-false-conditional" label. Can someone confirm that?
Azq2
commented
1 year ago I suspect this ticket should get the "my-in-false-conditional" label. Can someone confirm that?
Sure. Hmm... This is a known bug since 2003... 😱
ikegami
commented
1 year ago my if is explicitly documented as undefined behaviour.
To be specific, you're not allowed to use a variable without first running the my.
No, it's not a global var.
$ perl -e'
use feature qw( say );
sub f {
my $false = undef;
my $v if $false;
$v = $_[0] if @_;
$v
}
$v = 123;
say $v;
say f( "abc" );
say f();
say f( "def" );
say f();
say $v;
'
123
abc
abc
def
def
123It's still a lexically-scoped var, but it doesn't get cleared properly because the my didn't get executed.
Code:
Description When $cond is "constant false" then the perl bytecode optimizer removes dead code
my $v = 99999 if $cond;, but even withmy $vstatement.After this
$vgoes into a global variable!Steps to Reproduce Just run the code.
Expected behavior Optimizer must not remove the
my $vpart in this expression.Perl configuration