Hi. I'm trying to write a tool which would enable me to automatically determine the modules which are used when a specific module is loaded.

So, if Module::A uses Module::B which in turn uses Module::C I'd like to end up with a data structure that lets me know that Module::A uses Module::B uses Module::C in that order when Module::A is loaded.

To do that I'm trying to play around with %INC; here's what I've got so far. 
sub get_inc {
    my $module = shift;
    local %INC;
    eval { require $module };
    return keys %INC
}

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This allows me to inspect my local copy of %INC after a module has been required so that I can see what modules have been loaded after the fact.

However, the data returned doesn't provide any clues as to the order in which the modules were loaded. So I only know that then end result of requiring Module::A is that Module::B and Module::C were loaded; but I can't tell if Module::A loaded Module::C directly or if Module::C was loaded by Module::B.

So, what I am hoping to do is replace my local %INC with a tied hash that would allow me to inspect the contents of %INC as the modules are being 'required'.

Here are my questions:
  • Is it possible to manipulate %INC in this manner?
  • If not, is there another way to accomplish this?

    • I would like to avoid any solutions which involve the scanning of perl module files; at this point I'm hoping that the perl interpreter itself provides enough hooks to extract this information once a module has been required.

    In reply to Module Loading Tool by Anonymous Monk

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