Merge pull request rails#43581 from Shopify/as-notification-raise-single

Only wrap subscriber exceptions if there is more than one

Author: byroot

activerecord/test/cases/adapter_test.rb

@@ -213,11 +213,9 @@ def test_numeric_value_out_of_ranges_are_translated_to_specific_exception
     def test_exceptions_from_notifications_are_not_translated
       original_error = StandardError.new("This StandardError shouldn't get translated")
       subscriber = ActiveSupport::Notifications.subscribe("sql.active_record") { raise original_error }
-      wrapped_error = assert_raises(ActiveSupport::Notifications::InstrumentationSubscriberError) do
+      actual_error = assert_raises(StandardError) do
         @connection.execute("SELECT * FROM posts")
       end
-      actual_error = wrapped_error.exceptions.first
-
       assert_equal original_error, actual_error
 
     ensure

activerecord/test/cases/query_cache_test.rb

@@ -489,13 +489,11 @@ def test_query_cache_does_not_allow_sql_key_mutation
       payload[:sql].downcase!
     end
 
-    error = assert_raises ActiveSupport::Notifications::InstrumentationSubscriberError do
+    assert_raises FrozenError do
       ActiveRecord::Base.cache do
         assert_queries(1) { Task.find(1); Task.find(1) }
       end
     end
-
-    assert error.exceptions.first.is_a?(FrozenError)
   ensure
     ActiveSupport::Notifications.unsubscribe subscriber
   end

activesupport/lib/active_support/notifications/fanout.rb

@@ -93,8 +93,16 @@ def iterate_guarding_exceptions(listeners)
           exceptions ||= []
           exceptions << e
         end
-      ensure
-        raise InstrumentationSubscriberError.new(exceptions) unless exceptions.nil?
+
+        if exceptions
+          if exceptions.size == 1
+            raise exceptions.first
+          else
+            raise InstrumentationSubscriberError.new(exceptions), cause: exceptions.first
+          end
+        end
+
+        listeners
       end
 
       def listeners_for(name)

activesupport/test/notifications/evented_notification_test.rb

@@ -92,18 +92,23 @@ def test_listen_to_everything
         ], listener.events
       end
 
-      def test_listen_start_exception_consistency
+      def test_listen_start_multiple_exception_consistency
         notifier = Fanout.new
         listener = Listener.new
         notifier.subscribe nil, BadStartListener.new
+        notifier.subscribe nil, BadStartListener.new
         notifier.subscribe nil, listener
 
-        assert_raises InstrumentationSubscriberError do
+        error = assert_raises InstrumentationSubscriberError do
           notifier.start  "hello", 1, {}
         end
-        assert_raises InstrumentationSubscriberError do
+        assert_instance_of BadListenerException, error.cause
+
+        error = assert_raises InstrumentationSubscriberError do
           notifier.start  "world", 1, {}
         end
+        assert_instance_of BadListenerException, error.cause
+
         notifier.finish  "world", 1, {}
         notifier.finish  "hello", 1, {}
 
@@ -116,20 +121,24 @@ def test_listen_start_exception_consistency
         ], listener.events
       end
 
-      def test_listen_finish_exception_consistency
+      def test_listen_finish_multiple_exception_consistency
         notifier = Fanout.new
         listener = Listener.new
         notifier.subscribe nil, BadFinishListener.new
+        notifier.subscribe nil, BadFinishListener.new
         notifier.subscribe nil, listener
 
         notifier.start  "hello", 1, {}
         notifier.start  "world", 1, {}
-        assert_raises InstrumentationSubscriberError do
+        error = assert_raises InstrumentationSubscriberError do
           notifier.finish  "world", 1, {}
         end
-        assert_raises InstrumentationSubscriberError do
+        assert_instance_of BadListenerException, error.cause
+
+        error = assert_raises InstrumentationSubscriberError do
           notifier.finish  "hello", 1, {}
         end
+        assert_instance_of BadListenerException, error.cause
 
         assert_equal 4, listener.events.length
         assert_equal [