I updated things from source today and got an error when trying to view my 
agenda:

    M-x org-agenda
    t

showed the error

    Wrong type argument: stringp, nil

In *Messages* I saw:

    Press key for agenda command (unrestricted):
    org-agenda-get-todos: Wrong type argument: stringp, nil

I ran git bisect and narrowed it down to this (all else about my config 
remaining the same):

37d6bde27fe228cdadcb5cdaa09287872a508777 is the first bad commit
commit 37d6bde27fe228cdadcb5cdaa09287872a508777
Author: Ihor Radchenko <yantar92@posteo.net>
Date:   Tue Oct 10 13:53:07 2023 +0300

     org-element-parse-secondary-string: Prevent altering current buffer cache

I can't tell what's going on, but I hope this helps identify something.


Bill

--
William Denton
https://www.miskatonic.org/
Librarian, artist and licensed private investigator.
Toronto, Canada
CO₂: 418.33 ppm (Mauna Loa Observatory, 2023-10-09)