fix HABTM w/out primary key errors on destruction

activerecord/lib/active_record/associations/has_many_association.rb

@@ -111,7 +111,7 @@ def delete_records(records, method)
             records.each(&:destroy!)
             update_counter(-records.length) unless inverse_updates_counter_cache?
           else
-            if records == :all
+            if records == :all || !reflection.klass.primary_key
               scope = self.scope
             else
               scope = self.scope.where(reflection.klass.primary_key => records)

activerecord/test/cases/associations/has_and_belongs_to_many_associations_test.rb

@@ -775,6 +775,16 @@ def test_include_method_in_has_and_belongs_to_many_association_should_return_tru
     assert project.developers.include?(developer)
   end
 
+  def test_destruction_does_not_error_without_primary_key
+    redbeard = pirates(:redbeard)
+    george = parrots(:george)
+    redbeard.parrots << george
+    assert_equal 2, george.pirates.count
+    Pirate.includes(:parrots).where(parrot: redbeard.parrot).find(redbeard.id).destroy
+    assert_equal 1, george.pirates.count
+    assert_equal [], Pirate.where(id: redbeard.id)
+  end
+
   test "has and belongs to many associations on new records use null relations" do
     projects = Developer.new.projects
     assert_no_queries do