fix(voice): close lock-window gaps in accept, throttle, and call_attributes_changed?

enterprise/app/controllers/api/v1/accounts/whatsapp_calls_controller.rb

@@ -113,14 +113,28 @@ class Api::V1::Accounts::WhatsappCallsController < Api::V1::Accounts::BaseContro
   end
 
   # 138006 = no call permission yet; send opt-in template (throttled) and surface state to FE.
+  # Lock the conversation so concurrent initiate requests can't both pass the throttle gate
+  # and double-send the opt-in template.
   def render_permission_request
-    return render json: { status: 'permission_pending' } if permission_request_throttled?
+    status = nil
+    @conversation.with_lock do
+      if permission_request_throttled?
+        status = 'permission_pending'
+        next
+      end
 
-    sent = provider_service.send_call_permission_request(@conversation.contact.phone_number.delete('+'))
-    return render_could_not_create_error(I18n.t('errors.whatsapp.calls.permission_request_failed')) unless sent
+      sent = provider_service.send_call_permission_request(@conversation.contact.phone_number.delete('+'))
+      if sent
+        record_permission_request_wamid(sent)
+        status = 'permission_requested'
+      else
+        status = 'failed'
+      end
+    end
 
-    record_permission_request_wamid(sent)
-    render json: { status: 'permission_requested' }
+    return render_could_not_create_error(I18n.t('errors.whatsapp.calls.permission_request_failed')) if status == 'failed'
+
+    render json: { status: status }
   end
 
   def permission_request_throttled?

enterprise/app/models/enterprise/conversation.rb

@@ -40,6 +40,9 @@ module Enterprise::Conversation
   def call_attributes_changed?
     return false if previous_changes['additional_attributes'].blank?
 
-    previous_changes['additional_attributes'][1].keys.intersect?(%w[call_status call_direction])
+    # Compare before/after values for call keys — checking key presence alone
+    # rebroadcasts on any unrelated additional_attributes write once the keys exist.
+    before, after = previous_changes['additional_attributes']
+    %w[call_status call_direction].any? { |key| (before || {})[key] != (after || {})[key] }
   end
 end

enterprise/app/services/whatsapp/call_service.rb

@@ -4,10 +4,14 @@ class Whatsapp::CallService
   def accept
     raise Voice::CallErrors::CallFailed, 'sdp_answer is required' if sdp_answer.blank?
 
-    call.with_lock { transition_to_in_progress! }
-    update_message_status('in_progress')
-    update_conversation_call_status(call.display_status)
-    broadcast(:accepted, accepted_by_agent_id: agent.id)
+    # All side effects under the lock so a concurrent terminate cannot finalize
+    # the call between status update and the message/conversation/broadcast writes.
+    call.with_lock do
+      transition_to_in_progress!
+      update_message_status('in_progress')
+      update_conversation_call_status(call.display_status)
+      broadcast(:accepted, accepted_by_agent_id: agent.id)
+    end
     call
   end