1 files changed, 30 insertions, 4 deletions
diff --git a/lib/gitlab/json.rb b/lib/gitlab/json.rb
index 5ebda67e2ae..5b6689dbefe 100644
--- a/lib/gitlab/json.rb
+++ b/lib/gitlab/json.rb
@@ -2,13 +2,25 @@
 
 module Gitlab
   module Json
+    INVALID_LEGACY_TYPES = [String, TrueClass, FalseClass].freeze
+
     class << self
-      def parse(*args)
-        adapter.parse(*args)
+      def parse(string, *args, **named_args)
+        legacy_mode = legacy_mode_enabled?(named_args.delete(:legacy_mode))
+        data = adapter.parse(string, *args, **named_args)
+
+        handle_legacy_mode!(data) if legacy_mode
+
+        data
       end
 
-      def parse!(*args)
-        adapter.parse!(*args)
+      def parse!(string, *args, **named_args)
+        legacy_mode = legacy_mode_enabled?(named_args.delete(:legacy_mode))
+        data = adapter.parse!(string, *args, **named_args)
+
+        handle_legacy_mode!(data) if legacy_mode
+
+        data
       end
 
       def dump(*args)
@@ -28,6 +40,20 @@ module Gitlab
       def adapter
         ::JSON
       end
+
+      def parser_error
+        ::JSON::ParserError
+      end
+
+      def legacy_mode_enabled?(arg_value)
+        arg_value.nil? ? false : arg_value
+      end
+
+      def handle_legacy_mode!(data)
+        return data unless Feature.enabled?(:json_wrapper_legacy_mode, default_enabled: true)
+
+        raise parser_error if INVALID_LEGACY_TYPES.any? { |type| data.is_a?(type) }
+      end
     end
   end
 end