2024-02-14 13:10:38-05:00 - Don't want the first line of a git commit COMMIT_EDITMSG buffer in emacs to wrap?

Again, the trick is to use the Emacs variable fill-nobreak-predicate, but it's a bit trickier than my earlier example.

Don't want a line to break in emacs even in auto-fill-mode?

The code is very similar to the earlier code:

(defun tkb-magit-commit-fill-nobreak-p ()
  "Don't fill on the first line of a magit commit message."
  (= 1 (line-number-at-pos)))

(defun tkb-magit-commit-find-file-hook ()
  (when (string-match "COMMIT_EDITMSG\\'" (buffer-file-name))
    (make-local-variable 'fill-nobreak-predicate)
    (add-to-list 'fill-nobreak-predicate #'tkb-magit-commit-fill-nobreak-p)))
(add-to-list 'find-file-hook #'tkb-magit-commit-find-file-hook t)

The problem is that, depending on where the new hook ends up in the list find-file-hook, it may run after the git-commit-setup-check-buffer find file hook. This is a problem because git-commit-setup-check-buffer runs git-commit-setup which runs normal-mode which runs kill-all-local-variables, which wipes out what our code was trying to do. Sigh.

Instead, just specify the APPEND parameter to add-to-list as t:

(add-to-list 'find-file-hook #'tkb-magit-commit-find-file-hook t)

This adds our hook function at the end of the list, hopefully after git-commit-setup-check-buffer.

I've put this in a gist: