Remove blanket array delegation from `Relation`

As was pointed out by #17128, our blacklist of mutation methods was
non-exhaustive (and would need to be kept up to date with each new
version of Ruby). Now that `Relation` includes `Enumerable`, the number
of methods that we actually need to delegate are pretty small. As such,
we can change to explicitly delegating the few non-mutation related
methods that `Array` has which aren't on `Enumerable`

2 files changed, 2 insertions, 20 deletions

diff --git a/activerecord/lib/active_record/relation/delegation.rb b/activerecord/lib/active_record/relation/delegation.rb
index 27de313d05..b1333f110c 100644
--- a/activerecord/lib/active_record/relation/delegation.rb
+++ b/activerecord/lib/active_record/relation/delegation.rb
@@ -36,13 +36,8 @@ module ActiveRecord
     # may vary depending on the klass of a relation, so we create a subclass of Relation
     # for each different klass, and the delegations are compiled into that subclass only.
 
-    BLACKLISTED_ARRAY_METHODS = [
-      :compact!, :flatten!, :reject!, :reverse!, :rotate!, :map!,
-      :shuffle!, :slice!, :sort!, :sort_by!, :delete_if,
-      :keep_if, :pop, :shift, :delete_at, :select!
-    ].to_set # :nodoc:
-
-    delegate :to_xml, :to_yaml, :length, :collect, :map, :each, :all?, :include?, :to_ary, :join, to: :to_a
+    delegate :to_xml, :to_yaml, :length, :collect, :map, :each, :all?, :include?, :to_ary, :join,
+      :[], :&, :|, :+, :-, :sample, :reverse, :compact, to: :to_a
 
     delegate :table_name, :quoted_table_name, :primary_key, :quoted_primary_key,
              :connection, :columns_hash, :to => :klass
@@ -114,21 +109,14 @@ module ActiveRecord
 
     def respond_to?(method, include_private = false)
       super || @klass.respond_to?(method, include_private) ||
-        array_delegable?(method) ||
         arel.respond_to?(method, include_private)
     end
 
     protected
 
-    def array_delegable?(method)
-      Array.method_defined?(method) && BLACKLISTED_ARRAY_METHODS.exclude?(method)
-    end
-
     def method_missing(method, *args, &block)
       if @klass.respond_to?(method)
         scoping { @klass.public_send(method, *args, &block) }
-      elsif array_delegable?(method)
-        to_a.public_send(method, *args, &block)
       elsif arel.respond_to?(method)
         arel.public_send(method, *args, &block)
       else
diff --git a/activerecord/test/cases/relation/delegation_test.rb b/activerecord/test/cases/relation/delegation_test.rb
index 989f4e1e5d..b4269bd56d 100644
--- a/activerecord/test/cases/relation/delegation_test.rb
+++ b/activerecord/test/cases/relation/delegation_test.rb
@@ -40,12 +40,6 @@ module ActiveRecord
         assert_respond_to target, method
       end
     end
-
-    ActiveRecord::Delegation::BLACKLISTED_ARRAY_METHODS.each do |method|
-      define_method "test_#{method}_is_not_delegated_to_Array" do
-        assert_raises(NoMethodError) { call_method(target, method) }
-      end
-    end
   end
 
   class DelegationAssociationTest < DelegationTest