error with cache

["Fraga, Eric" <e.fraga@ucl.ac.uk>]

Hello all,

I use Emacs as my window manager (exwm).  I don't often restart as my
system is up 24/7.  Today, I had to restart and found Emacs hanging
during startup.  I added a debug on quit directive so I could see why.
The backtrace looks like this:

--8<---------------cut here---------------start------------->8---
Debugger entered--Lisp error: (quit)
  org-element--cache-active-p()
  org-element--parse-to(211)
  org-element-cache-map(#f(compiled-function (el) #<bytecode 0x14123237c7f8dc4b>) :next-re "\\<DEADLINE: *<\\([^>]+[0-9]\\{1,2\\}:[0-9]\\{2\\}[0-9+:hdwmy/ \11.-]*\\)>" :fail-re "\\<DEADLINE: *<\\([^>]+[0-9]\\{1,2\\}:[0-9]\\{2\\}[0-9+:hdwmy/ \11.-]*\\)>" :narrow t)
  org-agenda-get-deadlines(t)
  org-agenda-get-day-entries("/home/ucecesf/s/notes/ucltimetable.org" (12 17 2024) :deadline* :scheduled* :timestamp)
  org-agenda-to-appt()
  load-with-code-conversion("/home/ucecesf/s/emacs/esf-org.el" "/home/ucecesf/s/emacs/esf-org.el" nil nil)
  load("esf-org")
  load-with-code-conversion("/home/ucecesf/s/emacs/esf-common.el" "/home/ucecesf/s/emacs/esf-common.el" nil nil)
  load("~/s/emacs/esf-common")
  load-with-code-conversion("/home/ucecesf/.emacs" "/home/ucecesf/.emacs" t t)
  load("~/.emacs" noerror nomessage)
  #f(compiled-function () #<bytecode 0xf13c5274d3a4b11>)()
  startup--load-user-init-file(#f(compiled-function () #<bytecode 0x13ec00abe1cfb51>) #f(compiled-function () #cq
--8<---------------cut here---------------end--------------->8---

Asking Emacs to continue keeps it in an infinite loop of some sort.
Hitting C-g brings up a similar backtrace varying only in the argument
to org-element--parse-to.  Repeat ad nauseam.

The offending org file is automatically generated by cron from an ICS
file.  I tried resetting the cache but this did nothing.

I've removed the offending org file from the agenda list as my lectures
have finished so I don't need it and problem averted.  But I'm curious
to know what I could do in such a situation, should it arise again; I do
have two other agenda files that are also automatically generated.

For good measure, I've subsequently updated Emacs from git so the
version of org that was causing the error was from Emacs master from
last week.

Thank you,
eric

-- 
: Eric S Fraga, with org 9.7.17-3ae179 in Emacs 31.0.50