eglot seems to choke on Emacs 27

[damerell]

Running emacs 27 on Devuan chimaera (=~ Debian Bullseye), I installed eglot via M-x list-packages and "ccls" with "apt install ccls".

I then do "M-x eglot" in a buffer full of C++. The minibuffer says

[eglot] Connected! Server 'ccls' now managing `(c-mode c-ts-mode c++-mode c++-ts-mode objc-mode)' buffers in project 'crawl'.

(the above is a bit edited because it has literal backticks in...)

which is encouraging, but if I move point over any bit of the program it says "eldoc error: (void-fuction (setf plist-get))".

I tried replacing my .emacs with one which just reads

(custom-set-variables
 ;; custom-set-variables was added by Custom.
 ;; If you edit it by hand, you could mess it up, so be careful.
 ;; Your init file should contain only one such instance.
 ;; If there is more than one, they won't work right.
 '(package-selected-packages '(eglot gnu-elpa-keyring-update magit)))

I asked for help on r/emacs and was advised to install emacs 32 (so I did, and it works) but someone said it should work on emacs 27, please report a bug.

[joaotavora]

Yes, it was me, and it is a bug. This setf plist-get must be replaced with a plist-put. Shouldn't be too hard, but I won't have time till next week. Remind me of I forget, or try your hand at a small patch to bug-gnu-emacs@gnu.org.

[joaotavora]

OK, so it was fairly easy (I used cl-getf instead of plist-put) and I pushed this to emacs-31. It should quietly make its way into the so-called "GNU-devel elpa" repo https://elpa.gnu.org/devel/. You might want to use that repository instead of normal GNU ELPA in your Emacs 27 and test. Or you can wait for the next Eglot stable 1.24 release.