AssociationCollection#clear can basically just use #delete_all, except it should return self.

activerecord/lib/active_record/associations/association_collection.rb

@@ -112,6 +112,13 @@ module ActiveRecord
         end
       end
 
+      # Identical to delete_all, except that the return value is the association (for chaining)
+      # rather than the records which have been removed.
+      def clear
+        delete_all
+        self
+      end
+
       # Destroy all the records from this association.
       #
       # See destroy for more info.
@@ -191,19 +198,6 @@ module ActiveRecord
         load_target
       end
 
-      # Removes all records from this association.  Returns +self+ so method calls may be chained.
-      def clear
-        unless length.zero? # forces load_target if it hasn't happened already
-          if @reflection.options[:dependent] == :destroy
-            destroy_all
-          else
-            delete_all
-          end
-        end
-
-        self
-      end
-
       def create(attrs = {})
         if attrs.is_a?(Array)
           attrs.collect { |attr| create(attr) }

activerecord/test/cases/associations/has_many_associations_test.rb

@@ -662,8 +662,10 @@ class HasManyAssociationsTest < ActiveRecord::TestCase
   def test_delete_all
     force_signal37_to_load_all_clients_of_firm
     companies(:first_firm).clients_of_firm.create("name" => "Another Client")
-    assert_equal 2, companies(:first_firm).clients_of_firm.size
-    companies(:first_firm).clients_of_firm.delete_all
+    clients = companies(:first_firm).clients_of_firm.to_a
+    assert_equal 2, clients.count
+    deleted = companies(:first_firm).clients_of_firm.delete_all
+    assert_equal clients.sort_by(&:id), deleted.sort_by(&:id)
     assert_equal 0, companies(:first_firm).clients_of_firm.size
     assert_equal 0, companies(:first_firm).clients_of_firm(true).size
   end
@@ -683,11 +685,12 @@ class HasManyAssociationsTest < ActiveRecord::TestCase
     client_id = firm.clients_of_firm.first.id
     assert_equal 1, firm.clients_of_firm.size
 
-    firm.clients_of_firm.clear
+    cleared = firm.clients_of_firm.clear
 
     assert_equal 0, firm.clients_of_firm.size
     assert_equal 0, firm.clients_of_firm(true).size
     assert_equal [], Client.destroyed_client_ids[firm.id]
+    assert_equal firm.clients_of_firm.object_id, cleared.object_id
 
     # Should not be destroyed since the association is not dependent.
     assert_nothing_raised do