升级Ubuntu 24.04.1 LTS后Emacs因无法找到assoc函数导致配置加载失败

Hey there, sorry to hear you're stuck with this Emacs error after your Ubuntu upgrade! The assoc function is a core built-in in Emacs Lisp—so it’s really odd that it’s suddenly "missing" on your system. Let’s work through some fixes to get your config loading again:

First, let's confirm the basics #

First up, let’s rule out simple typos or early loading issues:

• Double-check your init file for any misspellings of assoc (like asoc or assocs)—it’s easy to fat-finger a character when editing configs.
• If you’re calling assoc very early in your init sequence (before Emacs has finished loading core libraries), try wrapping that code in a (after-init-hook) block to ensure it runs after Emacs is fully initialized:

  (add-hook 'after-init-hook
            (lambda ()
              ;; Your code using assoc here
              ))
  

Test with a minimal configuration #

Let’s isolate whether the problem is your config or a system-level issue. Create a temporary test file (say, test-assoc.el) with this content:

(message "Testing assoc function: %s" (assoc 'key '(("key" . "value") ("other" . "thing"))))

Then start Emacs with this command:

emacs -q --load ~/test-assoc.el

If you see the message Testing assoc function: ("key" . "value") in the Messages buffer (press C-h e to open it), that means assoc works fine on your system—so the issue is definitely in your original config file.

Dig into your config for conflicts #

If the minimal test works, check your main init file (and any included modules) for:

• Accidental redefinitions: Search for lines like (defun assoc (...) or (fset 'assoc ...)—someone might have overwritten this core function with a custom one, and the Emacs 29.3 upgrade broke that override. Rename any custom functions that clash with core names (e.g., my-custom-assoc instead of assoc).
• Outdated packages: Third-party packages (from ELPA/MELPA) that worked on Emacs 27 (the version in Ubuntu 22.04) might not be compatible with Emacs 29.3. Try starting Emacs with emacs -q (no config) and then install/update your packages one by one to spot the culprit.

Reinstall Emacs to fix system-level corruption #

If the minimal test also fails, there’s a chance some core Emacs files got corrupted during the Ubuntu upgrade. Try a clean reinstall:

sudo apt purge emacs emacs-gtk
sudo apt autoremove --purge
sudo apt install emacs-gtk

This will wipe the existing installation and install a fresh copy of Emacs 29.3 for Ubuntu 24.04.

问题重现细节 #

Just upgraded to 24.04.1 LTS, but my emacs configuration file can no longer load. Gives this error:
File is missing: Cannot open load file, No such file or directory, assoc

Seems lisp cannot find "assoc" any more. This worked just before upgrade from 22LTS.

GNU Emacs 29.3 (build 1, x86_64-pc-linux-gnu, GTK+ Version 3.24.41, cairo version 1.18.0) of 2024-04-01, modified by Debian

System info:

uname -a
Linux BBalien 6.8.0-45-generic #45-Ubuntu SMP PREEMPT_DYNAMIC Fri Aug 30 12:02:04 UTC 2024 x86_64 x86_64 x86_64 GNU/Linux

备注：内容来源于stack exchange，提问作者Ben Barrowes