Pluralized enum raises error when attempting to modify

[EByrdS]

Summary

Fixes #34514

The pluralized method created to access each enum now raises an error when attempting to modify the original.

Problem being addresed:

expected_copy = Model.states # {'foo'=>0, 'bar'=>1, 'baz'=>2}

# All the application would be silently affected with the following lines
expected_copy.delete('foo') # previously deleted foo from Model.states
expected_copy['bad_key'] = 10 # previously added a new key on Model.states

[composerinteralia]

What do you think about freezing enum_values instead? That way we would get an error if we try to mutate the values, rather than failing silently.

We would have to do it after all the values are set:

rails/activerecord/lib/active_record/enum.rb

Line 185 in 8f2caec

enum_values[label] = value

[EByrdS]

It seems a smarter way to fix it, will push the change.