bug#62164: 29.0.60; ediff behaves poorly by default on tiling window managers

[Spencer Baugh]

Eli Zaretskii <eliz@gnu.org> writes:

>> From: Spencer Baugh <sbaugh@janestreet.com>
>> Cc: luangruo@yahoo.com,  sbaugh@catern.com,  62164@debbugs.gnu.org
>> Date: Tue, 27 Jun 2023 21:13:09 -0400
>> 
>> * lisp/vc/ediff-wind.el (ediff-x-utility-control-frame): Add
>> defcustom.               ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
>
> Copy/pasta, right?
>
>> +(defcustom ediff-x-floating-control-frame nil
>
> A better name is ediff-floating-control-frame.
>
>> +  "If non-nil, the control frame will float under most X WMs.
>> +
>> +The control frame will be give the window type \"utility\".  On
>> +most tiling window managers, this will cause the control frame to
>> +be floating rather than tiled.  It should be harmless on other
>> +well-behaved window managers."
>
> I would document this slightly differently:
>
>     If not-nil, try making the control frame be floating rather than tiled.
>
>   If your X window manager makes the Ediff control frame a tiled one,
>   set this to a non-nil value, and Emacs will try to make it floating.
>   This only has effect on X displays.

OK, fixed these:

>From 5aea062fee4f265be146fd7df730ab077b31bb82 Mon Sep 17 00:00:00 2001
From: Spencer Baugh <sbaugh@janestreet.com>
Date: Tue, 9 May 2023 14:22:29 -0400
Subject: [PATCH] Allow floating the ediff control frame under X

This is a step in the direction of making ediff behave better by
default under tiling window managers and fixing bug#62164.

* lisp/vc/ediff-wind.el (ediff-floating-control-frame): Add
defcustom.
(ediff-frame-make-utility, ediff-setup-control-frame): Allow setting
the control frame up as a utility window under X. (bug#62164)
---
 lisp/vc/ediff-wind.el | 22 ++++++++++++++++++++++
 1 file changed, 22 insertions(+)

diff --git a/lisp/vc/ediff-wind.el b/lisp/vc/ediff-wind.el
index eb903f093f9..74e0e1f9b9f 100644
--- a/lisp/vc/ediff-wind.el
+++ b/lisp/vc/ediff-wind.el
@@ -69,6 +69,16 @@ ediff-window-setup-function
                 (function :tag "Other function"))
   :version "24.3")
 
+(defcustom ediff-floating-control-frame nil
+  "If not-nil, try making the control frame be floating rather than tiled.
+
+If your X window manager makes the Ediff control frame a tiled one,
+set this to a non-nil value, and Emacs will try to make it floating.
+This only has effect on X displays."
+  :type '(choice (const :tag "Control frame floats" t)
+                 (const :tag "Control frame has default WM behavior" nil))
+  :version "30.1")
+
 (ediff-defvar-local ediff-multiframe nil
   "Indicates if we are in a multiframe setup.")
 
@@ -873,6 +883,16 @@ ediff-window-ok-for-display
     (not (ediff-frame-has-dedicated-windows (window-frame wind)))
     )))
 
+(defun ediff-frame-make-utility (frame)
+  (let ((x-fast-protocol-requests t))
+    (x-change-window-property
+     "_NET_WM_WINDOW_TYPE" '("_NET_WM_WINDOW_TYPE_UTILITY")
+     frame "ATOM" 32 t)
+    (x-change-window-property
+     "WM_TRANSIENT_FOR"
+     (list (string-to-number (frame-parameter nil 'window-id)))
+     frame "WINDOW" 32 t)))
+
 ;; Prepare or refresh control frame
 (defun ediff-setup-control-frame (ctl-buffer designated-minibuffer-frame)
   (let ((window-min-height 1)
@@ -948,6 +968,8 @@ ediff-setup-control-frame
     (goto-char (point-min))
 
     (modify-frame-parameters ctl-frame adjusted-parameters)
+    (when (and ediff-floating-control-frame (eq (window-system ctl-frame) 'x))
+      (ediff-frame-make-utility ctl-frame))
     (make-frame-visible ctl-frame)
 
     ;; This works around a bug in 19.25 and earlier.  There, if frame gets
-- 
2.39.3