I am having trouble making the mount command here idempotent. I think it should work the way I've written it, but it isn't.

mount-devpts.yaml

---
# I want to verify that /dev/pts is mounted, and if not, mount it.
# Manually, this is simply: mount devpts /dev/pts -t devpts
# I want the resulting playbook to be idempotent and support the --check flag

- hosts: test
  remote_user: testroot

  tasks:
  # The simple "command" way to do this.
  - name: mount devpts with command module (this is idempotent thanks to the creates bit but command does not support --check)
    command: "mount devpts /dev/pts -t devpts"
    args:
      creates: /dev/pts/ptmx
  # The better way to do this, with the "mount" module.
  - name: mount devpts with mount module (not idempotent, --check says changed every time)
    mount: 
      path: /dev/pts
      src: devpts # I think this could be the issue but unsure how to best do this
      fstype: devpts
      state: present

...

The second option using the mount module appears to be idempotent only after the first run where it makes the mount... weird.

Some folks in the ansible IRC explained that this is because mount mostly/only cares about fstab and that I should be looking at udev instead.