From 08aeb01b0f681a706c173ec47a27e3b76a8011ba Mon Sep 17 00:00:00 2001
From: Jonathan Hefner <jonathan@hefner.pro>
Date: Sun, 31 May 2020 15:28:24 -0500
Subject: [PATCH] Lazily build path regex in PathParser

Eagerly building the path regex can exclude handlers which are added on
Action View load.

Fixes #39492.
---
 actionview/lib/action_view/template/resolver.rb | 5 +----
 railties/test/application/rendering_test.rb     | 4 +++-
 2 files changed, 4 insertions(+), 5 deletions(-)

diff --git a/actionview/lib/action_view/template/resolver.rb b/actionview/lib/action_view/template/resolver.rb
index b04a7cab66..aefb3b19c0 100644
--- a/actionview/lib/action_view/template/resolver.rb
+++ b/actionview/lib/action_view/template/resolver.rb
@@ -36,10 +36,6 @@ module ActionView
     end
 
     class PathParser # :nodoc:
-      def initialize
-        @regex = build_path_regex
-      end
-
       def build_path_regex
         handlers = Template::Handlers.extensions.map { |x| Regexp.escape(x) }.join("|")
         formats = Template::Types.symbols.map { |x| Regexp.escape(x) }.join("|")
@@ -60,6 +56,7 @@ module ActionView
       end
 
       def parse(path)
+        @regex ||= build_path_regex
         match = @regex.match(path)
         {
           prefix: match[:prefix] || "",
diff --git a/railties/test/application/rendering_test.rb b/railties/test/application/rendering_test.rb
index bf2382695f..38cc3b75fe 100644
--- a/railties/test/application/rendering_test.rb
+++ b/railties/test/application/rendering_test.rb
@@ -77,7 +77,9 @@ module ApplicationTests
             source
           end
         end
-        ActionView::Template.register_template_handler(:rubby, RubbyHandler)
+        ActiveSupport.on_load :action_view do
+          ActionView::Template.register_template_handler(:rubby, RubbyHandler)
+        end
       RUBY
 
       get "/"