Add Channel#ensure_confirmation_sent; call #subscribe_to_channel after initializing

2 files changed, 20 insertions, 25 deletions

diff --git a/actioncable/lib/action_cable/channel/base.rb b/actioncable/lib/action_cable/channel/base.rb
index 1d9038b76a..a866044f95 100644
--- a/actioncable/lib/action_cable/channel/base.rb
+++ b/actioncable/lib/action_cable/channel/base.rb
@@ -145,22 +145,13 @@ module ActionCable
         # When a channel is streaming via pubsub, we want to delay the confirmation
         # transmission until pubsub subscription is confirmed.
         #
-        # We use atomic fixnum to track the number of waiting tasks to avoid race conditions
+        # The counter starts at 1 because it's awaiting a call to #subscribe_to_channel
         @defer_subscription_confirmation_counter = Concurrent::AtomicFixnum.new(1)
 
         @reject_subscription = nil
         @subscription_confirmation_sent = nil
 
         delegate_connection_identifiers
-        subscribe_to_channel
-      end
-
-      # This method is called after subscription has been added to the channel.
-      # Send confirmation here to avoid race conditions when client tries to perform actions
-      # right after receiving confirmation.
-      def registered!
-        @defer_subscription_confirmation_counter.decrement
-        transmit_subscription_confirmation unless defer_subscription_confirmation?
       end
 
       # Extract the action name from the passed data and process it via the channel. The process will ensure
@@ -179,6 +170,17 @@ module ActionCable
         end
       end
 
+      # This method is called after subscription has been added to the connection
+      # and confirms or rejects the subscription.
+      def subscribe_to_channel
+        run_callbacks :subscribe do
+          subscribed
+        end
+
+        reject_subscription if subscription_rejected?
+        ensure_confirmation_sent
+      end
+
       # Called by the cable connection when it's cut, so the channel has a chance to cleanup with callbacks.
       # This method is not intended to be called directly by the user. Instead, overwrite the #unsubscribed callback.
       def unsubscribe_from_channel # :nodoc:
@@ -211,22 +213,24 @@ module ActionCable
           end
         end
 
+        def ensure_confirmation_sent
+          return if subscription_rejected?
+          @defer_subscription_confirmation_counter.decrement
+          transmit_subscription_confirmation unless defer_subscription_confirmation?
+        end
+
         def defer_subscription_confirmation!
           @defer_subscription_confirmation_counter.increment
         end
 
         def defer_subscription_confirmation?
-          @defer_subscription_confirmation_counter.value.positive?
+          @defer_subscription_confirmation_counter.value > 0
         end
 
         def subscription_confirmation_sent?
           @subscription_confirmation_sent
         end
 
-        def registered?
-          @registered
-        end
-
         def reject
           @reject_subscription = true
         end
@@ -244,14 +248,6 @@ module ActionCable
           end
         end
 
-        def subscribe_to_channel
-          run_callbacks :subscribe do
-            subscribed
-          end
-
-          reject_subscription if subscription_rejected?
-        end
-
         def extract_action(data)
           (data["action"].presence || :receive).to_sym
         end
diff --git a/actioncable/lib/action_cable/channel/streams.rb b/actioncable/lib/action_cable/channel/streams.rb
index c9b58f3a04..e480b93df0 100644
--- a/actioncable/lib/action_cable/channel/streams.rb
+++ b/actioncable/lib/action_cable/channel/streams.rb
@@ -84,8 +84,7 @@ module ActionCable
 
         connection.server.event_loop.post do
           pubsub.subscribe(broadcasting, handler, lambda do
-            @defer_subscription_confirmation_counter.decrement
-            transmit_subscription_confirmation unless defer_subscription_confirmation?
+            ensure_confirmation_sent
             logger.info "#{self.class.name} is streaming from #{broadcasting}"
           end)
         end