Unsubscribe all built-in subscribers

Fixes roidrage#385

Assumes that a built-in subscriber is nested under the component
namespace, so under ActionView or ActionController.

lib/lograge.rb

@@ -121,11 +121,18 @@ def unsubscribe(component, subscriber)
     events = subscriber.public_methods(false).reject { |method| method.to_s == 'call' }
     events.each do |event|
       Lograge.notification_listeners_for("#{event}.#{component}").each do |listener|
-        ActiveSupport::Notifications.unsubscribe listener if listener.instance_variable_get('@delegate') == subscriber
+        ActiveSupport::Notifications.unsubscribe listener if built_in_rails_listener?(listener, component)
       end
     end
   end
 
+  def built_in_rails_listener?(listener, component)
+    delegate = listener.instance_variable_get('@delegate')
+
+    # Assume that anything nested under the component namespace is built in to Rails
+    delegate.class.name.start_with?("#{component.to_s.classify}::")
+  end
+
   def setup(app)
     self.application = app
     disable_rack_cache_verbose_output

spec/lograge_spec.rb

@@ -1,5 +1,7 @@
 # frozen_string_literal: true
 
+require 'support/custom_listener'
+
 require 'active_support'
 require 'active_support/notifications'
 require 'active_support/core_ext/string'
@@ -21,24 +23,34 @@
         Lograge.remove_existing_log_subscriptions
       end.to change {
         Lograge.notification_listeners_for('process_action.action_controller')
-      }
+      }.to([])
     end
 
     it 'removes subscribers for all events' do
       expect do
         Lograge.remove_existing_log_subscriptions
       end.to change {
         Lograge.notification_listeners_for('render_template.action_view')
-      }
+      }.to([])
     end
 
-    it "does not remove subscribers that aren't from Rails" do
-      blk = -> {}
-      ActiveSupport::Notifications.subscribe('process_action.action_controller', &blk)
-      Lograge.remove_existing_log_subscriptions
-      listeners = Lograge.notification_listeners_for('process_action.action_controller')
-      expect(listeners.size).to eq(1)
+    shared_examples 'preserving non-Rails subscribers' do |event_name|
+      context "with event_name #{event_name}" do
+        it "does not remove subscribers that aren't from Rails" do
+          proc_subscriber = ActiveSupport::Notifications.subscribe(event_name, proc {})
+          custom_subscriber =
+            ActiveSupport::Notifications.subscribe(event_name, CustomListener.new)
+
+          Lograge.remove_existing_log_subscriptions
+
+          listeners = Lograge.notification_listeners_for(event_name)
+          expect(listeners).to contain_exactly(proc_subscriber, custom_subscriber)
+        end
+      end
     end
+
+    include_examples 'preserving non-Rails subscribers', 'render_template.action_view'
+    include_examples 'preserving non-Rails subscribers', 'process_action.action_controller'
   end
 
   describe 'keep_original_rails_log option' do

spec/support/custom_listener.rb

@@ -0,0 +1,11 @@
+class CustomListener
+  attr_reader :events
+
+  def initialize
+    @events = []
+  end
+
+  def call(*args)
+    @events << args
+  end
+end