Perl regex not breaking out of until loop as expected

Question

When I print the result of the regex I am attempting to use to control the until loop it gives me the 1 or null I am expecting. Why is it that the code below won't work but if I uncomment the fifth line it works fine?

print("Please enter 1, 2, 3 or 4 : ");
my $channelSelection = "";

until ($channelSelection =~ /^[1-4]$/) {
    chomp(my $channelSelection = <STDIN>);
    #last if ($channelSelection =~ /^[1-4]$/);
    print ("Invalid choice ($channelSelection) please try again: ") 
        if ($channelSelection !~ /[1-4]/);
}

I'm sure this has been solved elsewhere but was unable to find it with search. Pointing me in the right direction would be great.

I would normally do something like.

print("Please enter 1, 2, 3 or 4 : ");
my $channelSelection = "";
while (1) {
    chomp(my $channelSelection = <STDIN>);
    last if ($channelSelection =~ /^[1-4]$/);
    print ("Invalid choice ($channelSelection) please try again: ") if ($channelSelection !~ /[1-4]/);
}

But I'm trying to get away from the infinite loops.

Answer 1

The problem here is you're re-declaring the $channelSelection within the loop but the outside of the loop keeps the old value. Remove the "my" from the inner loop.

Answer 2

You have redeclared $channelSelection locally within the until loop. That way, its value will be lost every time the loop executes. So the regular expression will not match as the then value of $channelSelection will again be equal to "".

Removal of my from within the loop will solve the issue.