New cop: Dangerous name for column and enum

[pocke]

Is your feature request related to a problem? Please describe.

Some keywords, which is allowed by AR, conflict Rails features.
The most popular example is "type". It conflicts with STI.

And we can find other examples.

class C < ApplicationRecord
  enum x: {
    :present, # It breaks C#present?
    :none,
}
end

Describe the solution you'd like

Detect the dangerous names by RuboCop.

Describe alternatives you've considered

In the enum case, we can use _prefix: true option instead.
So the cop should be aware of the option.

Additional context

I think we need more examples for the cop. If you have any idea, please comment to this issue!

I was inspired by ruby-jp members. Thanks a lot!

[pocke]

Rails has detecting conflict feature, but I cannot get any errors with enum and present. I'm not sure why I cannot get it. I guess we need to investigate the rails code.
https://github.com/rails/rails/blob/e3ed320cb44f042f01d64e75278aa502789b2fe5/activerecord/lib/active_record/enum.rb#L251-L261

[tomasv]

I have another case. With Rails 6 enum now autogenerates negated scopes for each enum value as well and it becomes dangerous to have enum values starting with not_.

Consider a case like this:

class MyModel < ApplicationRecord
  enum status: {
    not_foo: 1,
    foo: 2,
    bar: 3,
  }
end

MyModel.not_foo.to_sql generates WHERE status != 2, which isn't
nice, because we actually expect WHERE status = 1.

It does throw a warning but warnings often get swallowed by CI environments.

[ybiquitous]

FYI. The next Rails version (7.1?) may cause runtime errors when using some dangerous methods from Object:

• Extend dangerous attribute methods with dangerous methods from Object rails/rails#45883
• Add frozen to dangerous methods rails/rails#46394