How to kill magit-diff's buffers on quit?

Question

After making a commit in magit, magit will leave around a magit-diff buffer containing just:

 Staged changes
(empty)
[back]

This is pretty useless and clutters up my buffers, and I'd just like that buffer to be killed off not just after a commit but whenever magit is done with it and empties it out like this.

This question is similar to How to kill ediff's buffers on quit?, only the accepted answer there (to use the ediff-quit-hook) won't work here because there's no corresponding magit-diff-quit-hook, as far as I can see.

Any help is greatly appreciated.

Answer 1

This answer takes the other answers and the comments into account, offering better ways of doing the same things. Your original question was about deleting the diff buffer after committing, though the other answers concentrated on doing something when quitting the status buffer. So I will do that first too, but later also tell you how to do something when you are done committing.

---

All that magit-mode-bury-buffer does is (funcall magit-bury-buffer-function kill-buffer). So there is no need to bind another home-made command to replace it or to advice it - just use the existing option intended to tweak the quitting behavior: magit-bury-buffer-function. This is also documented in the manual.

This command's primary purpose is to make the previously current buffer "go away", but you can also use it to do something to other buffers.

Here is how to get to other relevant buffers:

• magit-mode-get-buffers lists the other Magit buffers belonging to the current repository.
• magit-mode-get-buffer returns a particular buffer belonging to the current repository, matching the provided arguments.

---

To do something when you press C-c C-c in a commit message buffer use with-editor-post-finish-hook (a pre variant also exists, as do two cancel variants). These hooks are primarily intended for package authors who use the with-editor library (like git-commit.el does), so they are a bit under-documented and odd to use. To add something to such a hook for the benefit of git-commit-mode do something like:

(add-hook 'git-commit-setup-hook
          (lambda ()
            (add-hook 'with-editor-post-finish-hook
                      (lambda ()
                        ...)   ; your stuff here
                      nil t))) ; the t is important

But use named functions instead of lambdas.

Answer 2

Here is the working solution I ultimately wound up using. It is based on tarsius' advice, who deserves all the credit.

(defun kill-magit-diff-buffer-in-current-repo (&rest _)
  "Delete the magit-diff buffer related to the current repo"
  (let ((magit-diff-buffer-in-current-repo
         (magit-mode-get-buffer 'magit-diff-mode)))
    (kill-buffer magit-diff-buffer-in-current-repo)))
;;
;; When 'C-c C-c' is pressed in the magit commit message buffer,
;; delete the magit-diff buffer related to the current repo.
;;
(add-hook 'git-commit-setup-hook
          (lambda ()
            (add-hook 'with-editor-post-finish-hook
                      #'kill-magit-diff-buffer-in-current-repo
                      nil t))) ; the t is important

Answer 3

I had the same problem and I fixed it changing the "q" keybinding in magit-mode-map to run (magit-mode-bury-buffer t), which kills the buffer when burying it

To test it within the current session:

(define-key magit-mode-map 
   (kbd "q") 
   (lambda() (interactive) (magit-mode-bury-buffer t)))

You can add it to your startup config with use-package

(use-package magit
   :ensure t
   :config (define-key magit-mode-map 
             (kbd "q") 
             (lambda() (interactive) (magit-mode-bury-buffer t))))

Answer 4

For general reference - extending izkon's solution to also work when canceling (C-c C-k):

    (defun kill-magit-diff-buffer-in-current-repo (&rest _)
      "Delete the magit-diff buffer related to the current repo"
      (let ((magit-diff-buffer-in-current-repo (magit-mode-get-buffer 'magit-diff-mode)))
        (kill-buffer magit-diff-buffer-in-current-repo)))
    ;;
    ;; When 'C-c C-c' or 'C-c C-l' are pressed in the magit commit message buffer,
    ;; delete the magit-diff buffer related to the current repo.
    ;;    
    (add-hook 'git-commit-setup-hook
              (lambda ()
                (add-hook 'with-editor-post-finish-hook #'kill-magit-diff-buffer-in-current-repo
                          nil t)
                (add-hook 'with-editor-post-cancel-hook #'kill-magit-diff-buffer-in-current-repo
                          nil t)))