Merge pull request #15037 from roccoblues/fix_duplicate_activesupport_subscribers

Fixed duplicate subscribers in ActiveSupport::Subscriber

Conflicts:
	activesupport/CHANGELOG.md

1 files changed, 19 insertions, 6 deletions

diff --git a/activesupport/test/subscriber_test.rb b/activesupport/test/subscriber_test.rb
index 253411aa3d..8be8c51f07 100644
--- a/activesupport/test/subscriber_test.rb
+++ b/activesupport/test/subscriber_test.rb
@@ -4,20 +4,27 @@ require 'active_support/subscriber'
 class TestSubscriber < ActiveSupport::Subscriber
   attach_to :doodle
 
-  cattr_reader :event
+  cattr_reader :events
 
   def self.clear
-    @@event = nil
+    @@events = []
   end
 
   def open_party(event)
-    @@event = event
+    events << event
   end
 
   private
 
   def private_party(event)
-    @@event = event
+    events << event
+  end
+end
+
+# Monkey patch subscriber to test that only one subscriber per method is added.
+class TestSubscriber
+  def open_party(event)
+    events << event
   end
 end
 
@@ -29,12 +36,18 @@ class SubscriberTest < ActiveSupport::TestCase
   def test_attaches_subscribers
     ActiveSupport::Notifications.instrument("open_party.doodle")
 
-    assert_equal "open_party.doodle", TestSubscriber.event.name
+    assert_equal "open_party.doodle", TestSubscriber.events.first.name
+  end
+
+  def test_attaches_only_one_subscriber
+    ActiveSupport::Notifications.instrument("open_party.doodle")
+
+    assert_equal 1, TestSubscriber.events.size
   end
 
   def test_does_not_attach_private_methods
     ActiveSupport::Notifications.instrument("private_party.doodle")
 
-    assert_nil TestSubscriber.event
+    assert_equal TestSubscriber.events, []
   end
 end