Installation not helpfully stalling when db already exists

If I am installing Drupal and I forgot to remove my existing database, instead of getting a helpful message like "Your database is not empty", I am instead getting this unhelpful message and the install is stalled.

Luckily you can use the Back arrow in the browser and try again. But the message should be more helpful like it is if you can't connect or if you don't have a writeable settings.php file etc.