Eli Zaretskii <eliz@gnu.org> writes:
What is the package that relies on the old behavior?
js2-mode, see bug #12326 (merged with this one).
I'm confused. You just said that js2-mode needed a code change:
The one I posted in #12326: calling timer-activate-when-idle with nil
DONT-WAIT argument.
I don't think that's a workaround. I think that's what js2 should do,
if (AFAIU) it wants the timer handler be invoked once, after Emacs has
been idle for more than 1 sec.
If I understand correctly, js2-mode (prior to the workaround) assumed
the new behavior: it called run-with-idle-timer from inside the idle
timer, with the same delay, with the intention of scheduling for the
next period of idleness.