All these changes to avoid:
,----
| mu4e/meson.build:92: WARNING: Source item '/home/djcb/Sources/mu/build/mu4e/mu4e-meta.el' cannot be converted to File object, because it is a generated file. This will become a hard error in the future
`----
This is because we want to byte-compile a file we just before generated using
configure_file. This does not seem like a crazy thing, but meson threatens with
breaking the build at some point in the future.
So instead, we decide _not_ to compile this (very boring) file. But, users may
still have an older mu4e-meta.elc lying around, leading to confusion.
So, let's rename that file and we're golden.
This allows to have a function returning a window as value of
`mu4e-split-view`. I'm using this patch since quite some time locally with the
following function.
```el
(defun th/mu4e-split-view ()
(let* ((headers (mu4e-get-headers-buffer))
(headers-win (and headers (get-buffer-window headers)))
(view (mu4e-get-view-buffer))
(view-win (and view (get-buffer-window view))))
(cond
;; There's a view window, just use it.
(view-win view-win)
;; Just one window, split sensibly, i.e., horizontally or
;; vertically depending on geometry.
((one-window-p) (split-window-sensibly))
;; Otherwise, use the tallest window.
(t (car (sort (delq headers-win (window-list))
(lambda (a b)
(> (window-height a) (window-height b)))))))))
(setq mu4e-split-view #'th/mu4e-split-view)
```
It actually returns a buffer-name whereas it should return a buffer
object which make `mu4e~switch-back-to-mu4e-buffer` fail because
`buffer-live-p` expects a buffer object.
Usurp more of the utils code than can be re-used without further dependencies in
helpers.
Split off specific parts in their own file.
After the helper/utils changes, update the rest of mu4e to take the changes into
account.
Dirk-Jan C. Binnema
Tassilo Horn
Thierry Volpiatto