In previous versions (before 2.3) M-x magit-status showed the status buffer taking the whole size of the current window. However, now it instead pops up a half-sized buffer (like e.g. C-h f does). This looked fine but only until I wanted to review a diff of changes, as then it became apparent I want a full-sized window with the status buffer.
Is it possible to return the previous behavior of M-x magit-status?
Magit itself did never make the status buffer full screen. But many starter-kits do that and there also exist a few blog posts which explain how to do it. You are probably using such a starter-kit or a snippet you found somewhere, and that code stopped working due to changes in Magit v2.3.
These changes are actually intended to make it easier to customize how Magit buffers are displayed and switched to, but apparently these changes also break some existing kludges which were previously used to accomplish the same without any explicit support in Magit.
Starting with v2.3 Magit displays all Magit (-mode derived) buffers
using magit-display-buffer which in turn calls the function
specified by the option magit-display-buffer-function. The default
value is magit-display-buffer-traditional which displays the buffer
in much the same way as in previous releases. All the rules which
control how certain Magit buffers are displayed are now contained in
this function, previously they were scattered all over the place.
You can learn more about this in Switching Buffers from the Magit manual and in Choosing a Window for Display from the Elisp manual.
Once you have found a satisfactory solution to make the status buffer full screen (which uses "display actions" instead of third party packages), then please post that here.
magit-display-buffer-function to (lambda (buffer) (switch-to-buffer buffer) (selected-window)).
magit-display-buffer-traditional is supposed to display the buffer as it would traditionally have been displayed, and I think it mostly succeeds in that. What broke is a third-party hack and I now provide a way to implement that without using a hack. Implementing that is quite simple, though not as trivial as the snippet you posted.
(if (derived-mode-p 'magit-status-mode) ....
This is what I was doing before Magit 2.3, adapted from What the .emacs.d!?:
(defadvice magit-status (around magit-fullscreen activate)
"Turn fullscreen on for magit-status."
(window-configuration-to-register :magit-fullscreen)
ad-do-it
(delete-other-windows))
(defun magit-quit-session ()
"Restore previous window configuration and cleanup buffers."
(interactive)
(mu-kill-buffers "^\\*magit")
(jump-to-register :magit-fullscreen))
(bind-key "q" #'magit-quit-session magit-status-mode-map)
(defun mu-kill-buffers (regexp)
"Kill buffers matching REGEXP without asking for confirmation."
(interactive "sKill buffers matching this regular expression: ")
(cl-letf (((symbol-function 'kill-buffer-ask)
(lambda (buffer) (kill-buffer buffer))))
(kill-matching-buffers regexp)))
The difference from the solution on What the .emacs.d!? is that I like q to close all Magit buffers and not only magit-status.
If you don't have bind-key, you can just use regular define-key:
(define-key magit-status-mode-map (kbd "q") #'magit-quit-session)
Following the new Magit guidelines, this is the solution that is now working for me:
(setq magit-post-display-buffer-hook
#'(lambda ()
(when (derived-mode-p 'magit-status-mode)
(delete-other-windows))))
magit-display-buffer, which is a wrapper around the low-leveldisplay-buffer... " There is some additional discussion about how to customize buffer display behavior via themagit-display-buffer-functionoption, but I haven't experimented with this yet.