Separate camelize and classify lookup

[Be-ngt-oH]

What is the purpose of this pull request?

I've noticed a difference between how the lookup for symbols works in a Rails vs a non-Rails context. When in a non-Rails context, the symbol gets camelized, whereas in Rails, we classify it. For example, if given :users, in a non-Rails environment, we're looking for UsersPolicy. In Rails, we'd be looking for UserPolicy.

This PR updates the lookup to allow exact matches in Rails as well, e.g. when you don't want to or can't use Rails inflection. As a side-benefit, this PR makes the difference in behaviour between Rails and non-Rails a bit clearer.

What changes did you make? (overview)

First, we add a new lookup that uses camelize. By renaming the Symbol extension from classify to camelize this maintains the old behaviour in the non-Rails case and allows the exact matching symbols in the Rails case (:users -> UsersPolicy).

Second, we change the existing lookup to check whether classify is available, so it's skipped in the non-Rails case. This second lookup keeps it working in the Rails context (:users -> UserPolicy).

Finally, we've updated the documentation to describe the added behaviour.

PR checklist:

• Tests included
• Documentation updated
• Changelog entry added

[Be-ngt-oH]

I have updated the PR to incorporate your ideas. I'd really like to add some tests around the Rails vs non-Rails behaviour but didn't quite manage to do it yet. I have explored two options:

1. One way is requiring active_support/core_ext/string/inflections at the top. This would allows us to write tests against the classify lookup. However, we cannot do the opposite.
2. I've tried doing something with a String refinement that just adds classify (calling ActiveSupport::Inflector::classify). The lookup chain is set when the Lookup module is loaded, so you'd need to change that or reload the module. I tried the latter but then didn't manage to undo it without reloading the chain in every single test. I also had trouble scoping the refinement to just one testing class.

The case where you'd have a symbol as a plural and lookup the policy as the singular was not tested previously but I'd really like to add it. I'd be super grateful for ideas on this!

[palkan]

We run tests in isolation on CI, so Rails-specific tests (such as railtie_test) do not affect others. You can use rake test:isolated to do the same locally.

You can add one test under test/rails directory (say, test/rails/lookup_chain_test.rb), which loads dummy app first and only then loads test_helper (which in its turn requires action_policy). To make it kinda compatible with rake test, we need to check whether Action Policy has been loaded or not:

# test/rails/lookup_chain_test.rb
require_relative "./dummy/config/environment"

# we can skip this test file altogether if Action Policy has been loaded
return if defined?(ActionPolicy)
require "test_helper"

# or we can reload the lookup chain
# (that would require moving current `self.chain = ...` into a new `reload!` method)
ActionPolicy::LookupChain.reload!

Similarly, the non-Rails test would include return if defined?(Rails) on top of it (if we don't want to run it in the Rails context).

[Be-ngt-oH]

We run tests in isolation on CI, so Rails-specific tests (such as railtie_test) do not affect others. You can use rake test:isolated to do the same locally.

You can add one test under test/rails directory (say, test/rails/lookup_chain_test.rb), which loads dummy app first and only then loads test_helper (which in its turn requires action_policy). To make it kinda compatible with rake test, we need to check whether Action Policy has been loaded or not

Brilliant idea - Thank you very much for that! I was now able to update the branch with tests asserting the new behaviour.

[palkan]

Thanks!