>

my $var = "<value>"
        if <condition>;
[download]

Yeah, that's a classic (and FAQ IIRC)

Short answer: my has also an runtime effect° to default the value to undef .

But that is bypassed here by the condition.

Do this instead:

 my $var; 
 $var = "<value>" if <condition>;
[download]

update

°) "undocumented implementation detail" may be more precise

See also

• perlsyn#Statement-Modifiers:

  NOTE: The behaviour of a my, state, or our modified with a statement modifier conditional or loop construct (for example, my $x if ...) is undefined. The value of the my variable may be undef, any previously assigned value, or possibly anything else. Don't rely on it. Future versions of perl might do something different from the version of perl you try it out on. Here be dragons.