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

["Basil L. Contovounesios" via "Bug reports for GNU Emacs, the Swiss army knife of text editors" <bug-gnu-emacs@gnu.org>]

Philip Kaludercic [2021-10-08 11:03 +0000] wrote:

> "Basil L. Contovounesios" <contovob@tcd.ie> writes:
>> 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 see, it might be necessary to consider examples where this might go
> wrong.

Off the top of my head there's also ivy-quit-and-run in the ivy package,
but Lars pointed to effectively the same idiom.

>> 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?
>
> Because you might want to delay certain things, such as highlighting or
> completion.

What I meant is, the choice whether to run-with-timer or funcall can be
left to the calling package, since it knows better what it wants to do.

Thanks,

-- 
Basil