fix: assignee_changed callback not getting triggered during conversation creation (#9334)

The reload method in our callback was refreshing the object and hence the saved_change_to_assignee_id? Method wasn't working in the following callbacks.

This impacted the listeners subscribing to the event `ASSIGNEE_CHANGE`, `TEAM_CHANGE` etc

app/dispatchers/async_dispatcher.rb

@@ -10,14 +10,15 @@ class AsyncDispatcher < BaseDispatcher
 
   def listeners
     [
+      AutomationRuleListener.instance,
       CampaignListener.instance,
       CsatSurveyListener.instance,
       HookListener.instance,
       InstallationWebhookListener.instance,
       NotificationListener.instance,
+      ParticipationListener.instance,
       ReportingEventListener.instance,
-      WebhookListener.instance,
-      AutomationRuleListener.instance
+      WebhookListener.instance
     ]
   end
 end

app/listeners/participation_listener.rb

@@ -0,0 +1,8 @@
+class ParticipationListener < BaseListener
+  include Events::Types
+
+  def assignee_changed(event)
+    conversation, _account = extract_conversation_and_account(event)
+    conversation.conversation_participants.find_or_create_by!(user_id: conversation.assignee_id) if conversation.assignee_id.present?
+  end
+end

app/models/concerns/assignment_handler.rb

@@ -38,7 +38,6 @@ module AssignmentHandler
 
   def process_assignment_changes
     process_assignment_activities
-    process_participant_assignment
   end
 
   def process_assignment_activities
@@ -49,10 +48,4 @@ module AssignmentHandler
       create_assignee_change_activity(user_name)
     end
   end
-
-  def process_participant_assignment
-    return unless saved_change_to_assignee_id? && assignee_id.present?
-
-    conversation_participants.find_or_create_by!(user_id: assignee_id)
-  end
 end

app/models/concerns/auto_assignment_handler.rb

@@ -15,7 +15,6 @@ module AutoAssignmentHandler
     return unless should_run_auto_assignment?
 
     ::AutoAssignment::AgentAssignmentService.new(conversation: self, allowed_agent_ids: inbox.member_ids_with_assignment_capacity).perform
-    conversation_participants.find_or_create_by(user_id: assignee_id) if assignee_id.present?
   end
 
   def should_run_auto_assignment?

app/models/conversation.rb

@@ -110,7 +110,7 @@ class Conversation < ApplicationRecord
 
   after_update_commit :execute_after_update_commit_callbacks
   after_create_commit :notify_conversation_creation
-  after_commit :set_display_id, unless: :display_id?
+  after_create_commit :load_attributes_created_by_db_triggers
 
   delegate :auto_resolve_duration, to: :account
 
@@ -257,8 +257,13 @@ class Conversation < ApplicationRecord
     assignee_id.present? && Current.user&.id == assignee_id
   end
 
-  def set_display_id
-    reload
+  def load_attributes_created_by_db_triggers
+    # Display id is set via a trigger in the database
+    # So we need to specifically fetch it after the record is created
+    # We can't use reload because it will clear the previous changes, which we need for the dispatcher
+    obj_from_db = self.class.find(id)
+    self[:display_id] = obj_from_db[:display_id]
+    self[:uuid] = obj_from_db[:uuid]
   end
 
   def notify_status_change