bug#38457: 27.0.50; dabbrev-expand regression due to message change

[Eli Zaretskii]

> From: Juri Linkov <juri@linkov.net>
> Cc: 38457@debbugs.gnu.org,  stephen.berman@gmx.net
> Date: Thu, 12 Dec 2019 01:28:10 +0200
> 
> When message-in-echo-area is non-nil, then 'message' has exactly
> the same behavior as before, as in the previous versions.
> 
> I propose to use timers in minibuffer-message conditionally
> only when message-in-echo-area is nil.  Then the behavior
> of minibuffer-message will be exactly the same as before too
> when message-in-echo-area is non-nil.
> 
> If you want to set message-in-echo-area to t in the release branch,
> that's fine.

That would mean bring back all the problems for which these changes
were made.  So it would be the worst of all worlds, and thus makes
very little sense to me.

And in any case, minibuffer-message already behaves differently: it
logs the message in *Messages*, something it never did and is not
documented, and you suggested another change, to make it start the
debugger per debug-on-message.  These change behavior of any direct
callers of minibuffer-message in incompatible ways, something I don't
think we have a good reason to do.