Hi!

I can confirm that my previous issue is indeed solved in my case 🎉

I ran into another thing now trying to implement belongs-to-many relations.

The private custom_default_value method fails with undefined method 'default' for nil on this line:

def column_default_value
  owner.class.columns_hash[source_attr].default
end

When I debug, it turns out that source_attr is a symbol but columns_hash has string keys.

I'm not sure if the fix just is to to_s the symbol or if it should be changed deeper in the code. (Just changing to use to_s locally makes my code work).

The line in my code that triggers this, is when I try to assign to the association with something like my_model.tags = [my_tag], but I guess the line in question could be reached in many way.