1 files changed, 6 insertions, 0 deletions
diff --git a/activerecord/lib/active_record/coders/yaml_column.rb b/activerecord/lib/active_record/coders/yaml_column.rb
index fb59d9fb07..66a0c83c41 100644
--- a/activerecord/lib/active_record/coders/yaml_column.rb
+++ b/activerecord/lib/active_record/coders/yaml_column.rb
@@ -15,6 +15,12 @@ module ActiveRecord
       end
 
       def dump(obj)
+        return if obj.nil?
+
+        unless obj.is_a?(object_class)
+          raise SerializationTypeMismatch,
+            "Attribute was supposed to be a #{object_class}, but was a #{obj.class}. -- #{obj.inspect}"
+        end
         YAML.dump obj
       end