Respect validation_mode for external .herb templates

lib/reactionview/template/handlers/erb.rb

@@ -11,7 +11,9 @@ class ERB < ActionView::Template::Handlers::ERB
         def call(template, source)
           return super unless intercept_template?(template)
 
-          ::ReActionView::Template::Handlers::Herb.call(template, source)
+          ::ReActionView::Template::Handlers::Herb.call(
+            template, source, validation_mode: herb_validation_mode(template)
+          )
         rescue StandardError => e
           raise unless fall_back_to_erb?(template)
 
@@ -28,6 +30,13 @@ def intercept_template?(template)
           local_template?(template) || ReActionView.config.external_template_mode != :skip
         end
 
+        def herb_validation_mode(template)
+          return nil if local_template?(template)
+          return nil unless ReActionView.config.external_template_mode == :fallback
+
+          :raise
+        end
+
         def fall_back_to_erb?(template)
           !local_template?(template) && ReActionView.config.external_template_mode == :fallback
         end

lib/reactionview/template/handlers/herb.rb

@@ -10,7 +10,11 @@ class Herb < ActionView::Template::Handlers::ERB
 
         class_attribute :erb_implementation, default: Handlers::Herb::Herb
 
-        def call(template, source)
+        def self.call(template, source, validation_mode: nil)
+          new.call(template, source, validation_mode: validation_mode)
+        end
+
+        def call(template, source, validation_mode: nil)
           visitors = []
 
           if ::ReActionView.config.debug_mode_enabled? && local_template?(template)
@@ -23,7 +27,7 @@ def call(template, source)
           config = {
             filename: template.identifier,
             project_path: Rails.root.to_s,
-            validation_mode: validation_mode_for(template),
+            validation_mode: validation_mode || ReActionView.config.validation_mode,
             content_for_head: reactionview_dev_tools_markup(template),
             visitors: visitors + ReActionView.config.transform_visitors,
           }
@@ -39,13 +43,6 @@ def layout_template?(template)
           template.identifier.include?("/layouts/")
         end
 
-        def validation_mode_for(template)
-          return ReActionView.config.validation_mode if local_template?(template)
-          return ReActionView.config.validation_mode if ReActionView.config.external_template_mode == :compile
-
-          :raise
-        end
-
         def active_support_editor
           return unless defined?(ActiveSupport::Editor)
           return if ActiveSupport::Editor.current.blank?

test/template/handlers/external_template_mode_test.rb

@@ -127,6 +127,28 @@ def compile(source, identifier)
     ReActionView.config.validation_mode = nil
   end
 
+  test "external .herb templates use the configured validation mode" do
+    ReActionView.config.external_template_mode = :fallback
+    ReActionView.config.validation_mode = :overlay
+
+    template = ActionView::Template.new(
+      INVALID,
+      "/gems/some_gem/app/views/x.html.herb",
+      ReActionView::Template::Handlers::Herb,
+      virtual_path: "x",
+      format: :html,
+      locals: []
+    )
+
+    compiled = Rails.stub(:root, Pathname.new(RAILS_ROOT)) do
+      ReActionView::Template::Handlers::Herb.call(template, INVALID)
+    end
+
+    assert_includes compiled, "data-herb-validation-error"
+  ensure
+    ReActionView.config.validation_mode = nil
+  end
+
   test "local template failures always raise, whatever the mode" do
     ReActionView.config.external_template_mode = :fallback
     ReActionView.config.validation_mode = :raise