[mu4e rfe] Let display-buffer-alist dictate compose buffers

[malb]

Is your feature request related to a problem? Please describe.

At present, I don't see how I can pass e.g. frame parameters to the mu4e-compose frame created by mu4e.

Describe the solution you'd like

An option to let display-buffer-alist do its thing. I suggest an additional option for mu4e-compose-switch: display-buffer-alist which translates to (mu4e--compose-switch-function) becoming a noop. In addition, I think switch-to-buffer in mu4e--compose-setup should be replaced by display-buffer.

Describe alternatives you've considered

I've patched this behaviour as follows:

Additional context

diff --git a/mu4e/mu4e-compose.el b/mu4e/mu4e-compose.el
index 082665a0..2830f9c9 100644
--- a/mu4e/mu4e-compose.el
+++ b/mu4e/mu4e-compose.el
@@ -776,13 +776,13 @@ Optionally, SWITCH determines how to find a buffer for the message
     (mu4e--context-autoswitch parent mu4e-compose-context-policy)
     (with-current-buffer
         (mu4e--compose-setup-buffer compose-type compose-func parent)
-      (funcall (or switch (mu4e--compose-switch-function)) (current-buffer))
+      ;; (funcall (or switch (mu4e--compose-switch-function)) (current-buffer))
       (unless (eq compose-type 'edit)
         (set-visited-file-name ;; make it a draft file
          (mu4e--draft-message-path (mu4e--message-basename) parent)))
       (mu4e--compose-setup-post compose-type parent)
       (setq buf (current-buffer))
-      (switch-to-buffer buf)
+      (display-buffer buf)
       (let* ((msgframe (selected-frame))
              (actions (list
                        (lambda () ;; kill frame when it was created for this

I then use:

(defun malb/frame-dispatch (buffer alist)
  "Assigning buffers to frames."
  (cond
   ;; a mu4e compose buffer
   ((eq (buffer-local-value 'major-mode buffer) 'mu4e-compose-mode)
    (malb/display-mu4e-draft-buffer buffer alist)
    nil)

   ((eq (buffer-local-value 'major-mode (current-buffer)) 'mu4e-compose-mode)
    (malb/switch-away-from-special-and-tab (string-match-p ".*helm.*" (buffer-name buffer)))
    nil)

   ;; an mu4e buffer
   ((or (malb/mu4e-buffer-p buffer nil))
    (malb/switch-to-mu4e)
    nil)

   ;; this is not a mu4e buffer but we’re in the mu4e frame
   ((and (string-match "*mu4e*" (frame-parameter nil 'name))
         (not (malb/mu4e-buffer-p buffer nil))
         (not (malb/regexp-match-p malb/mu4e-buffer-allowed-regexps (buffer-name buffer))))
    (malb/switch-away-from-special-and-tab (string-match-p ".*helm.*" (buffer-name buffer)))
    nil)

   (t nil)))

and

(defun malb/display-mu4e-draft-buffer (buffer alist)
  (display-buffer-pop-up-frame buffer
                               '((window-parameters . ((no-other-window . t)))
                                 (dedicated . t)
                                 (pop-up-frame-parameters . ((width . 82)
                                                             (malb/special-frame . t))))))

with the desired effect.

See https://github.com/malb/emacs.d/blob/master/malb.org#dispatch-buffers-to-frames and https://github.com/malb/emacs.d/blob/master/malb.org#window-management-1

[djcb]

I suppose when you let mu4e create the frame, it's a little too late to influence it; but gess what you could do is leave mu4e-compose-switch at its default, and handle the frame creation yourself with your display-buffer-alist customization?

[malb]

I don't think I can do this at present. The buffer is currently shown before being in mu4e-compose-mode (in mu4e--compose-setup-post) and I thus struggle to come up with a rule to "catch it". If I could make mu4e--compose-switch-function a noop then I know how to make it work.

[malb]

Resolved with 20878c8