singleton_method_added is being forwarded by FactoryBot::Evaluator

Due to https://github.com/thoughtbot/factory_bot/blob/b223c275191985f776ff294825660fce98b3c0cc/lib/factory_bot/evaluator.rb#L10
methods like singleton_method_added (coming from BasicObject) are undefined.

And then https://github.com/thoughtbot/factory_bot/blob/b223c275191985f776ff294825660fce98b3c0cc/lib/factory_bot/evaluator.rb#L81 will actually call singleton_method_added, and since the method is not there, will end up in method_missing:
https://github.com/thoughtbot/factory_bot/blob/b223c275191985f776ff294825660fce98b3c0cc/lib/factory_bot/evaluator.rb#L47-L51
which will forward it to SyntaxRunner.new.

singleton_method_added does nothing by default so that's probably why this was never noticed.

It's not necessarily a problem, but it also seems surprising.

Maybe FactoryBot::Evaluator should inherit from BasicObject, rather than undefine many methods, some of them which might have quite subtle effects like this?

I noticed this while investigating https://github.com/oracle/truffleruby/issues/2258.

Read lib/factory_bot/evaluator.rb at the referenced lines 10, 47-51, and 81 to trace how singleton_method_added reaches method_missing and SyntaxRunner. Compare the current method-undefinition approach with the proposed BasicObject inheritance, then verify the chosen behavior with regression coverage and the existing test suite.