I just tried it. You can't override use directly. If you override require, then use will know to pay attention to it only if you are in the package that is overridden. Which means that if you override CORE::require, you don't override use globally.

You could add a coderef to @INC, but no matter how you go about it, that will take a lot of work. First you need to implement the full handling of @INC, including coderefs that pass back filehandles and coderefs that pass back objects (then the INC method gets called). At this point there are three ways to go.

The simplest is to say that if you did not find the module, you are going to mark it as not loaded. This is sufficient for Jesse Vincent's use case.

Somewhat more complex is to add a __DIE__ handler so that if that module fails to compile you might be told about it.

The hardest is to manually try to detect whether the module successfully loaded, which would mean returning a filehandle that will track whether it was successfully read up to the end, or __END__ or __DATA__. (It is up to you whether to worry about the possibility of arriving at those tokens within strings.)

Even after all of this work, are you done? No! Because people sometimes create small helper classes within a file, and these are real. To handle those I'd suggest that any package that is found which has subroutines in it that you never saw anyone trying to load are to be considered successfully loaded. That also will cover modules that were loaded before Class::Sniff was.

I would say that the fact that overriding CORE::require doesn't override use should be documented as a bug. And I would stick with the simplest solution, which is that you only ignore modules that your coderef said were not found.

In reply to Re: How Can I Know If a Package is "Real"? by tilly
in thread How Can I Know If a Package is "Real"? by Ovid

Title:
Use:  <p> text here (a paragraph) </p>
and:  <code> code here </code>
to format your post, it's "PerlMonks-approved HTML":


  • Posts are HTML formatted. Put <p> </p> tags around your paragraphs. Put <code> </code> tags around your code and data!
  • Titles consisting of a single word are discouraged, and in most cases are disallowed outright.
  • Read Where should I post X? if you're not absolutely sure you're posting in the right place.
  • Please read these before you post! —
  • Posts may use any of the Perl Monks Approved HTML tags:
    a, abbr, b, big, blockquote, br, caption, center, col, colgroup, dd, del, details, div, dl, dt, em, font, h1, h2, h3, h4, h5, h6, hr, i, ins, li, ol, p, pre, readmore, small, span, spoiler, strike, strong, sub, summary, sup, table, tbody, td, tfoot, th, thead, tr, tt, u, ul, wbr
  • You may need to use entities for some characters, as follows. (Exception: Within code tags, you can put the characters literally.)
            For:     Use:
    & &amp;
    < &lt;
    > &gt;
    [ &#91;
    ] &#93;
  • Link using PerlMonks shortcuts! What shortcuts can I use for linking?
  • See Writeup Formatting Tips and other pages linked from there for more info.