Fix noisy log error (#1831)

* Fix noisy log error

We've been seeing this error in our test logs:

    Could not log "render_template.action_view" event.
    NoMethodError: undefined method `example_group' for nil:NilClass
    .../rspec-rails-3.6.0/lib/rspec/rails/view_rendering.rb:67:in `current_example_group'
    .../rspec-rails-3.6.0/lib/rspec/rails/view_rendering.rb:71:in `render_template'
    ...

This is while running an rspec rails feature spec using capybara, so
this is a separate thread running webrick. This was also during a before
block. In any case, this should probably fail gracefully when there is
no example.

While updating this code I got an "ExampleGroup doesn't respond to
render_views?", so built in that case too.

* Throw away the LogSubscriber and just log explicitly

Author: sj26

lib/rspec/rails/view_rendering.rb

@@ -61,20 +61,6 @@ def self.nullify_template_rendering(templates)
           end
         end
 
-        # @private
-        class LogSubscriber < ::ActiveSupport::LogSubscriber
-          def current_example_group
-            RSpec.current_example.example_group
-          end
-
-          def render_template(_event)
-            return if current_example_group.render_views?
-            info("  Template rendering was prevented by rspec-rails. Use `render_views` to verify rendered view contents if necessary.")
-          end
-        end
-
-        LogSubscriber.attach_to(:action_view)
-
         # Delegates all methods to the submitted resolver and for all methods
         # that return a collection of `ActionView::Template` instances, return
         # templates with modified source
@@ -117,6 +103,8 @@ def find_templates(*args)
       # @private
       class EmptyTemplateHandler
         def self.call(_template)
+          ::Rails.logger.info("  Template rendering was prevented by rspec-rails. Use `render_views` to verify rendered view contents if necessary.")
+
           %("")
         end
       end

spec/rspec/rails/view_rendering_spec.rb

@@ -47,14 +47,6 @@ def example.controller
           group.render_views true
           expect(group.new.render_views?).to be_truthy
         end
-
-        it "does not log a message that rendering was prevented" do
-          subscriber = RSpec::Rails::ViewRendering::EmptyTemplateResolver::LogSubscriber.new
-          allow(subscriber).to receive(:current_example_group).and_return group
-          expect(subscriber).to_not receive(:info)
-          group.render_views true
-          subscriber.render_template(nil)
-        end
       end
 
       context "with false" do
@@ -68,14 +60,6 @@ def example.controller
           group.render_views false
           expect(group.new.render_views?).to be_falsey
         end
-
-        it "logs a message that rendering was prevented" do
-          subscriber = RSpec::Rails::ViewRendering::EmptyTemplateResolver::LogSubscriber.new
-          allow(subscriber).to receive(:current_example_group).and_return group
-          expect(subscriber).to receive(:info).with /render_views/
-          group.render_views false
-          subscriber.render_template(nil)
-        end
       end
 
       it 'propogates to examples in nested groups properly' do