HTML forms with checkboxes for removing/deleting of associations also supply 'false' values. This leads to complications - one needs to have a "blank" _remove/_delete setters or set Model.strict_param_setting = false.
Model.strict_param_setting = false
Provided fix solves the problem by removing the flags from attributes hash. I've made two decisions, which you may want to reconsider:
Add tests for updating associated objects with _delete/_remove flags …
…set to false.
Avoid complications with _delete/_remove flags being passed to nested…
…_attributes_update if they are set to false: remove the _delete/_remove flags from attributes if deleting/removing the associated objects is configured. Do not modify the original attributes hash.
This looks good. I should have time to merge and test it on Monday. Thanks for the help!