Ensure actioncable connection is not a pinned connection

Fix thread safety issue in rails #53883

This was causing random errors in the db restore, generally during the first
run of the cypress test per rails boot.  Sometimes, it would hang.  Other
times, I'd get a segmentation fault.  Other times, Bad file descriptor (Errno::EBADF)
in actioncable-7.2.2.2/lib/action_cable/subscription_adapter/postgresql.rb:107:in `wait_for_notify'.

I found that the prior commit helps to ensure the trigger disable and enable
are both run and not just disabled in the the case of an error.  But, on top of
that, I found that rails had fixed a thread safety issue in action cable
subscriptions's usage of a database connections.

See: https://www.github.com/rails/rails/pull/53891 and https://www.github.com/rails/rails/issues/53883
"Action Cable must avoid using a pinned connection to subscribe to notifications as it can't be done in a thread safe way.

So it must ensure it has a dedicated connection for that."

Author: jrafanie

lib/extensions/ac_subscription_adapter_postgresql.rb

@@ -0,0 +1,29 @@
+module ActionCableSubscriptionAdapterPostgresqlPatch
+  def with_subscriptions_connection(&block) # :nodoc:
+    # Action Cable is taking ownership over this database connection, and will
+    # perform the necessary cleanup tasks.
+    # We purposely avoid #checkout to not end up with a pinned connection
+    ar_conn = ActiveRecord::Base.connection_pool.send(:new_connection)
+    pg_conn = ar_conn.raw_connection
+
+    verify!(pg_conn)
+
+    pg_conn.exec("SET application_name = #{pg_conn.escape_identifier(identifier)}")
+    yield pg_conn
+  ensure
+    ar_conn&.disconnect!
+  end
+end
+
+# https://www.github.com/rails/rails/pull/53891 and https://www.github.com/rails/rails/issues/53883
+# Backported to 7-2-stable in https://github.com/rails/rails/commit/3e6e684c259e139db22f471069cd2cc0720d4bb4
+# Not yet released.
+ActiveSupport.on_load(:action_cable) do
+  if ActionCable.version >= Gem::Version.new("7.2.3")
+    message = "Patching ActionCable::SubscriptionAdapter::PostgreSQL - this is no longer needed in Rails 7.2.3 or newer! See: #{__FILE__}"
+    Rails.logger.warn(message)
+    message = "\e[33m#{message}\e[0m" if $stdout.tty?
+    warn(message)
+  end
+  ActionCable::SubscriptionAdapter::PostgreSQL.prepend(ActionCableSubscriptionAdapterPostgresqlPatch)
+end

lib/manageiq/ui/classic.rb

@@ -1,6 +1,7 @@
 require "manageiq/ui/classic/engine"
 require "manageiq/ui/classic/version"
 require "extensions/ac_nested_params"
+require "extensions/ac_subscription_adapter_postgresql"
 
 module ManageIQ
   module UI