add strict argument checking to ActiveRecord callbacks

This ends up adding it to all save-related callbacks defined in `ActiveRecord::DefineCallbacks`, including e.g. `after_create`. Which should be fine: they didn't support `:on` in the first place.

1 files changed, 23 insertions, 0 deletions

diff --git a/activerecord/test/cases/callbacks_test.rb b/activerecord/test/cases/callbacks_test.rb
index b9ba51c730..e10a7b34c8 100644
--- a/activerecord/test/cases/callbacks_test.rb
+++ b/activerecord/test/cases/callbacks_test.rb
@@ -476,4 +476,27 @@ class CallbacksTest < ActiveRecord::TestCase
     child.save
     assert child.after_save_called
   end
+
+  def test_on_isnt_allowed
+    exception = assert_raises ArgumentError do
+      Class.new(ActiveRecord::Base) do
+        before_save(on: :create) {}
+      end
+    end
+    assert_equal "Unknown key: :on. Valid keys are: :if, :unless, :prepend", exception.message
+
+    exception = assert_raises ArgumentError do
+      Class.new(ActiveRecord::Base) do
+        around_save(on: :create) {}
+      end
+    end
+    assert_equal "Unknown key: :on. Valid keys are: :if, :unless, :prepend", exception.message
+
+    exception = assert_raises ArgumentError do
+      Class.new(ActiveRecord::Base) do
+        after_save(on: :create) {}
+      end
+    end
+    assert_equal "Unknown key: :on. Valid keys are: :if, :unless, :prepend", exception.message
+  end
 end