From 26259b06601f88ef52c6e05617e650caf44d8748 Mon Sep 17 00:00:00 2001
From: HParker <HParker@github.com>
Date: Wed, 9 Jun 2021 11:51:15 -0700
Subject: [PATCH] Use the lookup_context to find the correct template path

This replaces the controller/action method of finding a path with the lookup_context which should always find the same thing as the render method finds.
---
 .../metal/etag_with_template_digest.rb        |  2 +-
 actionpack/test/controller/render_test.rb     | 28 +++++++++++++++++++
 2 files changed, 29 insertions(+), 1 deletion(-)

diff --git a/actionpack/lib/action_controller/metal/etag_with_template_digest.rb b/actionpack/lib/action_controller/metal/etag_with_template_digest.rb
index 983bd745bd7c2..6607ed009e3f1 100644
--- a/actionpack/lib/action_controller/metal/etag_with_template_digest.rb
+++ b/actionpack/lib/action_controller/metal/etag_with_template_digest.rb
@@ -44,7 +44,7 @@ def determine_template_etag(options)
       # template digest from the ETag.
       def pick_template_for_etag(options)
         unless options[:template] == false
-          options[:template] || "#{controller_path}/#{action_name}"
+          options[:template] || lookup_context.find_all(action_name, _prefixes).first&.virtual_path
         end
       end
 
diff --git a/actionpack/test/controller/render_test.rb b/actionpack/test/controller/render_test.rb
index 54fa5dd8cb0c5..768baed4184f3 100644
--- a/actionpack/test/controller/render_test.rb
+++ b/actionpack/test/controller/render_test.rb
@@ -65,6 +65,12 @@ def hello_world
   end
 end
 
+class InheritedRenderTestController < ImplicitRenderTestController
+  def hello_world
+    fresh_when(etag: "abc")
+  end
+end
+
 class TestController < ActionController::Base
   protect_from_forgery
 
@@ -724,6 +730,28 @@ def test_etag_reflects_template_digest
   end
 end
 
+class InheritedEtagRenderTest < ActionController::TestCase
+  tests InheritedRenderTestController
+  include TemplateModificationHelper
+
+  def test_etag_reflects_template_digest
+    get :hello_world
+    assert_response :ok
+    assert_not_nil etag = @response.etag
+
+    request.if_none_match = etag
+    get :hello_world
+    assert_response :not_modified
+
+    modify_template("implicit_render_test/hello_world") do
+      request.if_none_match = etag
+      get :hello_world
+      assert_response :ok
+      assert_not_equal etag, @response.etag
+    end
+  end
+end
+
 class MetalRenderTest < ActionController::TestCase
   tests MetalTestController