Strange use of (run-with-timer 0 nil #'foo args) in do-after-load-evaluation

[Alan Mackenzie <acm@muc.de>]

Hello, Emacs.

In do-after-load-evaluation, we have the following, near the end:

          (run-with-timer 0 nil
                          (lambda (msg)
                            (message "%s" msg))
                          msg)

.  run-with-timer is being used to run message once, immediately.  Why
not just call message?

The reason I ask is that whilst loading my desktop, the prompt

        Please type y, n, or !, or C-v to scroll:

, asking me whether I want dangerous local variables to be loaded, is
getting obscured by the less important

        Package cl is deprecated

, and I have to know that I'm expected to respond to this obscured
prompt.  This has been happening to me only for a short time, at least a
week, but probably less than a month.

This last message about cl being deprecated is being output by the
strange run-with-timer.  If I replace the run-with-timer form with a
straight message call, I see the prompt from hack-local-variables.

What is going on, here?  Is the run-with-timer mechanism being used
deliberately to make the "deprecated" message prevail over other
messages?  If so, perhaps it shouldn't be.

<A bit later>

I've searched the git log, and found that cl was moved into lisp/obsolete
on 2019-08-06.  At the same time, some change was made to output the
"deprecated" message in do-after-load-evaluation.

The current situation seems unsatisfactory; the prompt from
hack-local-variables is more important than the deprecation message, and
shouldn't be obscured by it.

-- 
Alan Mackenzie (Nuremberg, Germany).