That's a classic "gotcha" in my book. That's one reason why I almost always write such code as:

{
    my @values;
    BEGIN { @values = ( 1 .. 3 ); }

    sub _test {
        # ...
    }
}
[download]

or, especially if the code is going into the main script for a mod_perl Apache::Registry page:

BEGIN {
    my @values = ( 1 .. 3 );

    sub _test {
        # ...
    }
}
[download]

Actually, that makes me wonder why I've been using the first form lately. I should switch back to the second form. Thanks for reminding me.

Oh, and to be extra clear, yes, it is easy to get caught by this problem (which is why I have a "practice" for preventing it).