bug#71699: 29.3; run-at-time early run

[Eli Zaretskii <eliz@gnu.org>]

> From: Christopher Howard <christopher@librehacker.com>
> Date: Fri, 21 Jun 2024 08:45:53 -0800
> 
> 
> emacs -Q
> M-x eval-expression
> (run-at-time "04:00" 86400 (lambda () (message "timer ran")))
> 
> >From the documentation, I expect this lambda to run in the future, at 4:00 in the morning. However, it also runs once when I first eval this run-at-time expression, i.e., when I setup the timer. From looking at list-timers, I can see that it will run again at 4 in the morning, which is good, but I do not want the function to run when the timer is first setup.
> 
> I tried a different approach, passing in a named function instead of a lambda, but got the same result.

I guess you evaluated the expression at time that was after 4AM that
day?  If so, this is expected behavior, because times are interpreted
as times _today_.  The ELisp manual says:

 -- Command: run-at-time time repeat function &rest args
     This sets up a timer that calls the function FUNCTION with
     arguments ARGS at time TIME.  If REPEAT is a number (integer or
     floating point), the timer is scheduled to run again every REPEAT
     seconds after TIME.  If REPEAT is ‘nil’, the timer runs only once.

     TIME may specify an absolute or a relative time.

     Absolute times may be specified using a string with a limited
     variety of formats, and are taken to be times _today_, even if
     already in the past.  The recognized forms are ‘XXXX’, ‘X:XX’, or
     ‘XX:XX’ (military time), and ‘XXam’, ‘XXAM’, ‘XXpm’, ‘XXPM’,
     ‘XX:XXam’, ‘XX:XXAM’, ‘XX:XXpm’, or ‘XX:XXPM’.

So I don't think this is a bug.