This change was necessary because the whitelist wouldn't work.
It would be painful for users trying to update their applications.
This blacklist intent to prevent odd bugs and confusion in code that call mutator
methods directely on the `Relation`.
addresses "ArgumentError: comparison of VerySpecialComment with SpecialComment failed" in ActiveRecord::DelegationRelationTest#test_#sort!_delegation_is_deprecated
Every method from MRI's core classes is written in C. This means
Method#arity always returns -1 for methods with a variable number of
arguments. This is not the case with Rubinius, where, for example
Array#slice! is implemented in Ruby and has arity -2, since is
defined as def slice!(start, length = undefined)
The primary means of returning results for Array bang methods is to modify
the array in-place. When you call these methods on a relation, that
array is created, modified, and then thrown away. Only the secondary
return value is exposed to the caller.
Removing this delegation is a straight-forward way to reduce user error
by forcing callers to first explicitly call #to_a in order to expose
the array to be acted on by the bang method.
