bug#51094: Check if run-with{-idle, }-timer needs to create a timer

[Basil L. Contovounesios]

Philip Kaludercic [2021-10-08 09:36 +0000] wrote:

> I have seen a few packages use run-with-timer or run-with-idle-timer,
> where the SECS parameter is configurable with a user option. When this
> timer doesn't repeat itself and it makes sense to set SECS to 0 when you
> want something to run immediately, I don't think it makes sense to
> create a timer object.

IIUC, the semantics of SECS=0 (alias nil) is not the same as eager
funcall, because timer functions are intended to be run asynchronously
in a separate command loop.  So often what is meant by "now" is e.g. "as
soon as I quit the current active minibuffer".

I realise this patch does not touch run-at-time, but it's documented as
being interchangeable with run-with-timer, so the eager funcall sounds
like a breaking change.

If packages indeed want to run something immediately, why create a timer
at all?  Or am I misunderstanding something?

Thanks,

-- 
Basil