Allow cas_logout() to be called from hook_user_logout()

+++ b/cas.moduleundefined
@@ -634,11 +634,26 @@ function cas_login_page($cas_first_login = FALSE) {
+ * This is safe to call from hook_user_logout() to ensure all Drupal logouts also logout CAS.

This is not technically safe to call from hook_user_logout(), as it does a drupal_goto() which will prevent later modules' hook_user_logout() from firing. :/

Not really sure if there is a way to get around this limitation.

From module_list():

By default, modules are ordered by weight and module name.

In Drupal 7, we have hook_module_implements_alter() which could be used to move a particular implementation of hook_user_logout to the very end...

Is the issue that we cannot call cas_logout from hook_user_logout because it'd become recursive? If this is the case, I think it'd be cleaner to have

function cas_logout($flag = TRUE) {
  // ...
  if ($flag) {
    module_invoke_all('user_logout', $user);
  }
  // ...
}

We'd have to choose an appropriate name for $flag, of course.

Thanks. I've attempted to clean up your patch to avoid extra noise and add some comments.

Out of curiosity, why is the watchdog message problematic?

Committed to 6.x-3.x and 7.x-1.x. Thanks for the original patch!