1 files changed, 6 insertions, 2 deletions
diff --git a/actionpack/lib/action_dispatch/middleware/debug_exceptions.rb b/actionpack/lib/action_dispatch/middleware/debug_exceptions.rb
index 61773d97a2..59113e13f4 100644
--- a/actionpack/lib/action_dispatch/middleware/debug_exceptions.rb
+++ b/actionpack/lib/action_dispatch/middleware/debug_exceptions.rb
@@ -60,7 +60,11 @@ module ActionDispatch
         log_error(request, wrapper)
 
         if request.get_header("action_dispatch.show_detailed_exceptions")
-          content_type = request.formats.first
+          begin
+            content_type = request.formats.first
+          rescue Mime::Type::InvalidMimeType
+            render_for_api_request(Mime[:text], wrapper)
+          end
 
           if api_request?(content_type)
             render_for_api_request(content_type, wrapper)
@@ -142,7 +146,7 @@ module ActionDispatch
           message = []
           message << "  "
           message << "#{exception.class} (#{exception.message}):"
-          message.concat(exception.annoted_source_code) if exception.respond_to?(:annoted_source_code)
+          message.concat(exception.annotated_source_code) if exception.respond_to?(:annotated_source_code)
           message << "  "
           message.concat(trace)