Add framework for preloading controllers

[kraih]

Summary

This is a less ambitious solution for #1607. It doesn't preload all possible controllers but leaves it up to the developer to configure the right namespaces. The default of MyApp::Controller might just work for most of our users though.

Motivation

More efficient memory usage. Detecting syntax errors in controllers much earlier (during application startup instead of at runtime).

References

#1607

[amenonsen]

For what it's worth, I read through this commit, and it looks good to me.

[Grinnz]

I like this approach especially as it can be easily configured to avoid preloading if someone was so inclined (e.g. CGI deployment).

[christopherraa]

👍

No objections from me. Surprised that this new functionality wasn't a bigger change.

[christopherraa]

One question as an after-thought: why default to MyApp::Controller? Does anyone really use that? If not, would it make more sense to default to whatever namespace the app is in, in the case of a full app? So if anyone has generated a Corp::App::Foo application, defaulting to preloading Corp::App::Foo::Controller::*. Too difficult or error-prone to detect perhaps?

[kraih]

When i say MyApp::Controller i of course mean "@{[ref $self]}::Controller" in code.

[marcusramberg]

I think this is a great addition to mojo. 👍