Rails fixes

These Rails fixes were driven by extensive testing of the newly released Rails
version 7.1, but some may be relevant to older Rails versions as well.

*lib/*
- When adding new segment attributes, anticipate and ignore numeric parameter
  keys
- For `Transaction#finish`, don't attempt to invoke methods on a non-existent
  initial segment

*test/*
- Inline controller method rendering with a proc was a thing in early Rails
  versions that was no longer supported in Rails 3. We were defining our own
  `proc_render` controller method to simulate the old style behavior and it
  finally caused issues for us in Rails 7. Given that we don't even support
  Rails versions older than 4 now, let's just stop testing the Rails 2 and
  below proc functionality.
- `ActiveJobTest`: a single test needed an additional `expect`
- Remove the temporary `before_suite.rb` based hacks for the Rails multiverse
  suite.
- Modify the `ActionController::Live` RUM test to set a `last-modified` header
  on the streaming response. This prevents Rack v3 from attempting to call
  `to_ary` on the streaming response object returned. In the future we could
  author a better streaming test that properly chunks data and possibly even
  uses a layout. But for now, this header fix gives us Rack 3 compatibility with
  the old test.

resolves #2254

lib/new_relic/agent.rb

@@ -633,7 +633,9 @@ def add_custom_attributes(params) # THREAD_LOCAL_ACCESS
     def add_new_segment_attributes(params, segment)
       # Make sure not to override existing segment-level custom attributes
       segment_custom_keys = segment.attributes.custom_attributes.keys.map(&:to_sym)
-      segment.add_custom_attributes(params.reject { |k, _v| segment_custom_keys.include?(k.to_sym) })
+      segment.add_custom_attributes(params.reject do |k, _v|
+        segment_custom_keys.include?(k.to_sym) if k.respond_to?(:to_sym) # param keys can be integers
+      end)
     end
 
     # Add custom attributes to the span event for the current span. Attributes will be visible on spans in the

lib/new_relic/agent/transaction.rb

@@ -520,7 +520,7 @@ def needs_middleware_summary_metrics?(name)
       end
 
       def finish
-        return unless state.is_execution_traced?
+        return unless state.is_execution_traced? && initial_segment
 
         @end_time = Process.clock_gettime(Process::CLOCK_REALTIME)
         @duration = @end_time - @start_time

test/multiverse/suites/rails/action_controller_live_rum_test.rb

@@ -13,6 +13,7 @@ def brains
     end
 
     def brain_stream
+      headers['last-modified'] = Time.now # tell Rack not to call #to_ary on the response object
       render(:inline => RESPONSE_BODY, :stream => true)
     end
   end

test/multiverse/suites/rails/activejob_test.rb

@@ -104,7 +104,7 @@ def test_code_information_recorded_with_new_transaction
         (NewRelic::Agent::Instrumentation::ActiveJobSubscriber::PAYLOAD_KEYS.size + 1).times do
           segment.expect(:params, {}, [])
         end
-        3.times do
+        4.times do
           segment.expect(:finish, [])
         end
         segment.expect(:record_scoped_metric=, nil, [false])

test/multiverse/suites/rails/view_instrumentation_test.rb

@@ -65,27 +65,14 @@ def collection_render
     render((1..3).map { |x| Foo.new })
   end
 
-  # proc rendering isn't available in rails 3 but you can do nonsense like this
-  # and assign an enumerable object to the response body.
-  def proc_render
-    streamer = Class.new do
-      def each
-        10_000.times do |i|
-          yield("This is line #{i}\n")
-        end
-      end
-    end
-    self.response_body = streamer.new
-  end
-
   def raise_render
     raise 'this is an uncaught RuntimeError'
   end
 end
 
 class ViewInstrumentationTest < ActionDispatch::IntegrationTest
   include MultiverseHelpers
-  RENDERING_OPTIONS = [:js_render, :xml_render, :proc_render, :json_render]
+  RENDERING_OPTIONS = [:js_render, :xml_render, :json_render]
 
   setup_and_teardown_agent do
     # ActiveSupport testing keeps blowing away my subscribers on
@@ -98,7 +85,7 @@ class ViewInstrumentationTest < ActionDispatch::IntegrationTest
     end
   end
 
-  (ViewsController.action_methods - %w[raise_render collection_render haml_render proc_render]).each do |method|
+  (ViewsController.action_methods - %w[raise_render collection_render haml_render]).each do |method|
     define_method("test_sanity_#{method}") do
       get "/views/#{method}"