Handle ActionView::PathSet immutability and strict type casting in Rails 7.1

[eugeneius]

Since rails/rails#45957, ActionView::PathSet is immutable, and only accepts subclasses of ActionView::Resolver. This necessitates changes to how RSpec Rails decorates resolvers to return blank templates when render_views? is false.

These changes fix the test suite when running against the Rails main branch:
https://github.com/rspec/rspec-rails/actions/runs/3340449858/jobs/5530555101

Co-authored by @ilianah 🍐

[pirj]

Thanks a lot @eugeneius and @ilianah !

[JonRowe]

Can you add a spec for this @eugeneius / @ilianah ? The linked build wasn't failing before this?

[pirj]

It was, it's just deceivingly green on GitHub:

  1) RSpec::Rails::ViewRendering when render_views? is false supports manipulating view paths with resolvers
     Failure/Error:
       expect {
         controller.prepend_view_path ActionView::Resolver.new
         controller.append_view_path ActionView::Resolver.new
       }.to_not raise_error

       expected no Exception, got #<NoMethodError: undefined method `unshift' for #<ActionView::PathSet:0x00007f6132d1d950 @paths=[]>> with backtrace:
         # ./spec/rspec/rails/view_rendering_spec.rb:142:in `block (4 levels) in <module:Rails>'
         # ./spec/rspec/rails/view_rendering_spec.rb:141:in `block (3 levels) in <module:Rails>'
         # ./spec/spec_helper.rb:74:in `block (3 levels) in <top (required)>'
         # ./spec/spec_helper.rb:68:in `block (2 levels) in <top (required)>'

[JonRowe]

Ah great, thats not obvious from the link

[JonRowe]

@pirj Can you add a changelog entry as you merged this

[pirj]

@JonRowe Already pushed 👍

[JonRowe]

Can you also cherry pick the merge and the changelog commit across to 6-0-maintenance if we're classing these as bug fixes.

[pirj]

Done 👍
My apologies for missing that step, I'm still new to our release management.

[JonRowe]

Released in 6.0.2