如何在调试器下运行Perl代码块？

Question

I'm writing a test for my debugger.

subtest "main" => sub {
    $ENV{PERL5DB} = 'Devel::AllSubs';
    my $stderr = capture_stderr {
        sub foo { bar(); }
        sub bar { 1; }
        foo();
    };
    $ENV{PERL5DB} = '';
    is $stderr, "main::foo\nmain::bar";
};

How to apply debugger to

{
sub foo { bar(); }
sub bar { 1; }
foo();
}

block ?

I tried to use $ENV{PERL5DB} but no effect.

Answer 1

You can't use $ENV{PERL5DB} the way you want.

1. It has to be the full command to load in the debugger code such as use Devel::AllSubs
2. It is only checked when Perl is started with a bare -d switch
3. It only gets checked when Perl starts as Perl needs to know that it is running the script under the debugger to create the op codes needed to enter the debugger.

So in order to apply your debugger to only part of the code you will need to first load it in using the -d switch like this

perl -d:AllSubs script.pl

and then use a package variable to decide if you want to process the code or not. Looking at your module name I assume you are trying to do something with each subroutine so your test probably wants to be in your DB::sub method