Merge pull request #35661 from jhawthorn/lookup_context_validation

Validate types assigned to LookupContext#formats=

2 files changed, 9 insertions, 1 deletions

diff --git a/actionview/lib/action_view/lookup_context.rb b/actionview/lib/action_view/lookup_context.rb
index 2eaf188ecf..fd3d025cbf 100644
--- a/actionview/lib/action_view/lookup_context.rb
+++ b/actionview/lib/action_view/lookup_context.rb
@@ -280,7 +280,15 @@ module ActionView
     # add :html as fallback to :js.
     def formats=(values)
       if values
+        values = values.dup
         values.concat(default_formats) if values.delete "*/*"
+        values.uniq!
+
+        invalid_values = (values - Template::Types.symbols)
+        unless invalid_values.empty?
+          raise ArgumentError, "Invalid formats: #{invalid_values.map(&:inspect).join(", ")}"
+        end
+
         if values == [:js]
           values << :html
           @html_fallback_for_js = true
diff --git a/actionview/lib/action_view/rendering.rb b/actionview/lib/action_view/rendering.rb
index ac861c44d4..5a06bd9da6 100644
--- a/actionview/lib/action_view/rendering.rb
+++ b/actionview/lib/action_view/rendering.rb
@@ -127,7 +127,7 @@ module ActionView
       # Assign the rendered format to look up context.
       def _process_format(format)
         super
-        lookup_context.formats = [format.to_sym]
+        lookup_context.formats = [format.to_sym] if format.to_sym
       end
 
       # Normalize args by converting render "foo" to render :action => "foo" and