What can make Class::Loader fail where "use" and "new" do not?

Question

I'm working on a very large CGI application that uses Crypt::RSA, which is properly installed. I get a "attempted to call a null reference as a function" type of error (I can't go back to get the exact error right now because we had to rollback for a release date) when I try to run any the embedded library. I trace the null reference to Crypt::RSA's constructor, which uses Class::Loader to enable Crypt::RSA::ES::OAEP.

I replaced the class loader with a "use" and a "new", and that part works fine, though the library still fails in many points. Obviously something is wrong with my environment. I'm just not certain as to what. Can anyone give me any leads?

Answer 1

Ok, after 12 hours of digging into it, I got this working.

Here's what was going on (but not why). Whenever I called eval() on a quoted use or require statement (as occurs in Class::Loader, but also in other locations in the Crypt:: framwork), it failed to see paths that were otherwise included as Perl classpaths. Since most quoted use/require objects simply assume the class will be there, very few useful errors were thrown out at me. I would dump @INC to file, outside an eval block, and everything would be there.

Ironically, I used the same setup in dev vs staging, and it worked in dev, but not in staging. I must also point out that FindBin (I shouldn't be using it in CGI, I know, but Crypt uses it) was flailing up and down about /dev/null in staging, but not in development.

Since I can't easily compare versions or global configs, that's where my quest ends.

How I resolved the issue for myself in Crypt::RSA was to disable all commands tied to FindBin, and hard-code require references for anything my code would ever access. I did a require in Crypt::RSA for Crypt::RSA::ES::OAEP and one in Crypt::Random::Generator for Crypt::Random::Provider::rand

Hope this helps anyone in the future who has the problem. Anyone who can suggest the why of it, please respond and I'll add it to complete the post.