1 files changed, 11 insertions, 8 deletions
diff --git a/activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb b/activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb
index 759ac9943f..200b773172 100644
--- a/activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb
+++ b/activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb
@@ -61,16 +61,13 @@ module ActiveRecord
           @collation = collation
           @extra     = extra
           super(name, default, cast_type, sql_type, null)
+          assert_valid_default(default)
         end
 
-        def extract_default(default)
-          if blob_or_text_column?
-            if default.blank?
-              null || strict ? nil : ''
-            else
-              raise ArgumentError, "#{type} columns cannot have a default value: #{default.inspect}"
-            end
-          elsif missing_default_forged_as_empty_string?(default)
+        def default
+          @default ||= if blob_or_text_column?
+            null || strict ? nil : ''
+          elsif missing_default_forged_as_empty_string?(@original_default)
             nil
           else
             super
@@ -102,6 +99,12 @@ module ActiveRecord
         def missing_default_forged_as_empty_string?(default)
           type != :string && !null && default == ''
         end
+
+        def assert_valid_default(default)
+          if blob_or_text_column? && default.present?
+            raise ArgumentError, "#{type} columns cannot have a default value: #{default.inspect}"
+          end
+        end
       end
 
       ##