Make AccessManager stricter with values returned from access checkers

Is there a reason why we haven't changed the actual values of these constants? Only that change ensures that we do use the proper values everywhere.

I will update the tests for TRUE, FALSE in the next patch.

Do you talk about the default access checker here? Maybe we could do that in another issue.

This should fix the test failures.

Adding some tags.

re-rtbc

+++ b/core/lib/Drupal/Core/Access/AccessManager.php
@@ -261,6 +261,11 @@ protected function checkAll(array $checks, Route $route, Request $request, Accou
+      if (!in_array($service_access, array(AccessInterface::ALLOW, AccessInterface::DENY, AccessInterface::KILL), TRUE)) {
+        throw new AccessException('Access services can only return AccessInterface::ALLOW, AccessInterface::DENY, or AccessInterface::KILL constants.');
+      }

Which access checker failed? If we're going to throw an exception with the expectation that it gets displayed, it should be helpful to the developer and say which access checker/method is Doing It Wrong(tm). That way it's easier to fix.

I like the idea of this patch on "fail usefully" grounds, but we should go all the way to failing very usefully.

Good point!

Committed/pushed to 8.x, thanks!