can/should x window managers depend on an X server?

[Ross Vandegrift <rvandegrift@debian.org>]

Hello,

I recently saw a user question regarding installing a window manager,
and then not being able to run it.  The user didn't have xorg installed:
they probably finished d-i with no desktop tasks selected in tasksel.
That crops up occasionally - I was curious if I could improve the
situation for those users.  I found two surprising things.

First, I didn't find a solution to copy: according to a quick search
[1], no x-window-manager package (directly) brings in an X server.  Some
will bring one in via another dependency (e.g. cinnamon -> cinnamon-core
-> lightdm -> Recommends: xserver-xorg)

Second, policy didn't really clarify. Sec 11.8.1 says:
> Programs that can be configured with support for the X Window System
> must be configured to do so and must declare any package dependencies
> necessary to satisfy their runtime requirements when using the X
> Window System.

Historically, I can think of some reasons why this once would've clearly
excluded an X server:
  1. it might not've been clear which X server to install
  2. X used to require elaborate config, with scary warnings
  3. someone might've wanted a window manager to be displayed remotely
The first two strike me as false now, and #3 is probably less common
than minimall installs.



So here's what I'm wondering:
- can x-window-manager packages depend/recommend/suggest an X server?
- should they?
- if so:
  - what should the relationship be?
  - what should the target be?
  - should these vary depending on the WM? (ie, twm probably still works
    well-enough remotely.  enlightenment not so much.)
  - should policy be updated?


Thanks for your thoughts,
Ross

[1] - grepping the output of "aptitude search -F %p ~Px-window-manager |
xargs apt show" for "xserver" and "xorg".