Deprecate rendering templates with . in the name

actionpack/test/controller/render_test.rb

@@ -365,7 +365,9 @@ def test_dynamic_render_with_absolute_path
   def test_dynamic_render
     assert File.exist?(File.expand_path("../../test/abstract_unit.rb", __dir__))
     assert_raises ActionView::MissingTemplate do
-      get :dynamic_render, params: { id: '../\\../test/abstract_unit.rb' }
+      assert_deprecated do
+        get :dynamic_render, params: { id: '../\\../test/abstract_unit.rb' }
+      end
     end
   end
 

actionpack/test/controller/renderer_test.rb

@@ -109,7 +109,7 @@ def test_render_component
     xml  = "<p>Hello world!</p>\n"
 
     assert_equal html, render["respond_to/using_defaults"]
-    assert_equal xml,  render["respond_to/using_defaults.xml.builder"]
+    assert_equal xml,  assert_deprecated { render["respond_to/using_defaults.xml.builder"] }
     assert_equal xml,  render["respond_to/using_defaults", formats: :xml]
   end
 

actionview/lib/action_view/template/resolver.rb

@@ -227,6 +227,10 @@ def reject_files_external_to_app(files)
       end
 
       def find_template_paths_from_details(path, details)
+        if path.name.include?(".")
+          ActiveSupport::Deprecation.warn("Rendering actions with '.' in the name is deprecated: #{path}")
+        end
+
         query = build_query(path, details)
         find_template_paths(query)
       end
@@ -331,6 +335,11 @@ def find_candidate_template_paths(path)
       end
 
       def find_template_paths_from_details(path, details)
+        if path.name.include?(".")
+          # Fall back to the unoptimized resolver, which will warn
+          return super
+        end
+
         candidates = find_candidate_template_paths(path)
 
         regex = build_regex(path, details)

actionview/test/template/fallback_file_system_resolver_test.rb

@@ -8,7 +8,7 @@ def setup
   end
 
   def test_should_have_no_virtual_path
-    templates = @root_resolver.find_all("hello_world.erb", "#{FIXTURE_LOAD_PATH}/test", false, locale: [], formats: [:html], variants: [], handlers: [:erb])
+    templates = @root_resolver.find_all("hello_world", "#{FIXTURE_LOAD_PATH}/test", false, locale: [], formats: [:html], variants: [], handlers: [:erb])
     assert_equal 1, templates.size
     assert_equal "Hello world!", templates[0].source
     assert_nil templates[0].virtual_path

actionview/test/template/render_test.rb

@@ -200,7 +200,9 @@ def test_render_partial_from_default
   def test_render_outside_path
     assert File.exist?(File.expand_path("../../test/abstract_unit.rb", __dir__))
     assert_raises ActionView::MissingTemplate do
-      @view.render(template: "../\\../test/abstract_unit.rb")
+      assert_deprecated do
+        @view.render(template: "../\\../test/abstract_unit.rb")
+      end
     end
   end
 
@@ -338,8 +340,10 @@ def test_render_partial_collection
   end
 
   def test_render_partial_collection_with_partial_name_containing_dot
-    assert_equal "Hello: davidHello: mary",
-      @view.render(partial: "test/customer.mobile", collection: [ Customer.new("david"), Customer.new("mary") ])
+    assert_deprecated do
+      assert_equal "Hello: davidHello: mary",
+        @view.render(partial: "test/customer.mobile", collection: [ Customer.new("david"), Customer.new("mary") ])
+    end
   end
 
   def test_render_partial_collection_as_by_string
@@ -579,7 +583,11 @@ def test_render_does_not_use_unregistered_extension_and_template_handler
   def test_render_ignores_templates_with_malformed_template_handlers
     %w(malformed malformed.erb malformed.html.erb malformed.en.html.erb).each do |name|
       assert File.exist?(File.expand_path("#{FIXTURE_LOAD_PATH}/test/malformed/#{name}~")), "Malformed file (#{name}~) which should be ignored does not exists"
-      assert_raises(ActionView::MissingTemplate) { @view.render(template: "test/malformed/#{name}") }
+      assert_raises(ActionView::MissingTemplate) do
+        ActiveSupport::Deprecation.silence do
+          @view.render(template: "test/malformed/#{name}")
+        end
+      end
     end
   end
 

actionview/test/template/resolver_shared_tests.rb

@@ -169,7 +169,7 @@ def test_templates_sort_by_formats_html_first
   def test_virtual_path_is_preserved_with_dot
     with_file "test/hello_world.html.erb", "Hello html!"
 
-    template = context.find("hello_world.html", "test", false, [], {})
+    template = assert_deprecated { context.find("hello_world.html", "test", false, [], {}) }
     assert_equal "test/hello_world.html", template.virtual_path
 
     template = context.find("hello_world", "test", false, [], {})