Run window change functions during redisplay

* doc/lispref/windows.texi (Window Sizes): Move (and rename)
descriptions of 'window-pixel-height-before-size-change' and
'window-pixel-width-before-size-change' to Window Hooks
section.
(Window Configurations): Remove warning against use of
'save-window-excursion' in 'window-size-change-functions'.
(Window Hooks): Rewrite section according to redesign of
window change functions.
* lisp/erc/erc-track.el (erc-window-configuration-change)
(erc-modified-channels-update): Call latter directly from
'window-configuration-change-hook' instead via
'post-command-hook'.
* lisp/frame.el (frame-size-changed-p): Change nomenclature
in let bindings.
* lisp/net/rcirc.el (rcirc-window-configuration-change)
(rcirc-window-configuration-change-1): Call latter directly
from 'window-configuration-change-hook' instead via
'post-command-hook'.
* lisp/window.el (window-pixel-width-before-size-change)
(window-pixel-height-before-size-change): Defalias.
(window--resize-mini-window, window-resize)
(adjust-window-trailing-edge, delete-window)
(delete-other-windows, balance-windows): Don't run
'window-configuration-change-hook' any more from here.
(split-window): Don't run 'window-configuration-change-hook'
from here.  'run-window-scroll-functions' from here.
(window--adjust-process-windows): Run from
'window-configuration-change-hook' only.
* src/frame.c (old_selected_frame): New Lisp variable.
(make_frame): Initialize frame's change_stamp slot.
(Fold_selected_frame): New function.
* src/frame.h (struct frame): New slots old_selected_window,
window_change, change_stamp and number_of_windows.
(fset_old_selected_window): New inlined function.
(FRAME_WINDOW_CHANGE, FRAME_OLD_SELECTED_WINDOW): New macros.
* src/window.c (old_selected_window): New Lisp variable.
(wset_old_buffer): New inlined function.
(Fframe_old_selected_window, Fold_selected_window)
(Fwindow_old_buffer): New functions.
(Fwindow_old_pixel_width, Fwindow_old_pixel_height): Rename
from Fwindow_pixel_width_before_size_change and
Fwindow_pixel_height_before_size_change.  Update doc-strings.
(Fwindow_old_body_pixel_width, Fwindow_old_body_pixel_height):
New functions.
(Fdelete_other_windows_internal): Set frame's window_change
slot instead of running 'window-configuration-change-hook'.
(Frun_window_configuration_change_hook): In doc-string tell
that this function is no more needed.
(Frun_window_scroll_functions): Amend doc-string.  Run with
window's buffer current.
(window_sub_list, window_change_record_windows)
(window_change_record_frame, window_change_record)
(run_window_change_functions_1, run_window_change_functions):
New functions.
(set_window_buffer): Set frame's window_change slot instead of
running 'window-configuration-change-hook'.
(make_window): Don't initialize pixel_width_before_size_change
and pixel_height_before_size_change slots.
(window_resize_apply, Fdelete_window_internal): Set frame's
window_change slot.
(Fsplit_window_internal): Set frame's window_change slot.
Don't run 'window-scroll-functions' from here.
* src/window.h (struct window): New slots old_buffer,
change_stamp, old_pixel_width (renamed from
pixel_width_before_size_change), old_pixel_height (renamed
from pixel_height_before_size_change), old_body_pixel_width
and old_body_pixel_height.
* src/xdisp.c (init_iterator): Set frame's window_change slot
when the body height or width changes.
(prepare_menu_bars): Don't run_window_size_change_functions.
(redisplay_internal): Don't run_window_size_change_functions,
run_window_change_functions instead.

4 files changed, 15 insertions, 39 deletions

diff --git a/lisp/erc/erc-track.el b/lisp/erc/erc-track.el
index c966cf86270..f42bd648725 100644
--- a/lisp/erc/erc-track.el
+++ b/lisp/erc/erc-track.el
@@ -640,7 +640,7 @@ only consider active buffers visible.")
   (unless (minibuffer-window-active-p (minibuffer-window))
     ;; delay this until command has finished to make sure window is
     ;; actually visible before clearing activity
-    (add-hook 'post-command-hook 'erc-modified-channels-update)))
+    (erc-modified-channels-update)))
 
 (defvar erc-modified-channels-update-inside nil
   "Variable to prevent running `erc-modified-channels-update' multiple
@@ -669,8 +669,7 @@ ARGS are ignored."
 		  (erc-modified-channels-remove-buffer buffer))))
 	    erc-modified-channels-alist)
       (when removed-channel
-	(erc-modified-channels-display)))
-    (remove-hook 'post-command-hook 'erc-modified-channels-update)))
+	(erc-modified-channels-display)))))
 
 (defvar erc-track-mouse-face (if (featurep 'xemacs)
 				 'modeline-mousable
diff --git a/lisp/frame.el b/lisp/frame.el
index 8341ba1707f..dc81302939e 100644
--- a/lisp/frame.el
+++ b/lisp/frame.el
@@ -1745,20 +1745,17 @@ for FRAME."
   (let* ((frame (window-normalize-frame frame))
          (root (frame-root-window frame))
          (mini (minibuffer-window frame))
-         (mini-height-before-size-change 0)
+         (mini-old-height 0)
          (mini-height 0))
     ;; FRAME's minibuffer window counts iff it's on FRAME and FRAME is
     ;; not a minibuffer-only frame.
     (when (and (eq (window-frame mini) frame) (not (eq mini root)))
-      (setq mini-height-before-size-change
-            (window-pixel-height-before-size-change mini))
+      (setq mini-old-height (window-old-pixel-height mini))
       (setq mini-height (window-pixel-height mini)))
     ;; Return non-nil when either the width of the root or the sum of
     ;; the heights of root and minibuffer window changed.
-    (or (/= (window-pixel-width-before-size-change root)
-            (window-pixel-width root))
-        (/= (+ (window-pixel-height-before-size-change root)
-               mini-height-before-size-change)
+    (or (/= (window-old-pixel-width root) (window-pixel-width root))
+        (/= (+ (window-old-pixel-height root) mini-old-height)
             (+ (window-pixel-height root) mini-height)))))
 
 ;;;; Frame/display capabilities.
diff --git a/lisp/net/rcirc.el b/lisp/net/rcirc.el
index 863554604e8..47681ccfe79 100644
--- a/lisp/net/rcirc.el
+++ b/lisp/net/rcirc.el
@@ -2064,9 +2064,7 @@ activity.  Only run if the buffer is not visible and
 (defvar rcirc-visible-buffers nil)
 (defun rcirc-window-configuration-change ()
   (unless (minibuffer-window-active-p (minibuffer-window))
-    ;; delay this until command has finished to make sure window is
-    ;; actually visible before clearing activity
-    (add-hook 'post-command-hook 'rcirc-window-configuration-change-1)))
+    (rcirc-window-configuration-change-1)))
 
 (defun rcirc-window-configuration-change-1 ()
   ;; clear activity and overlay arrows
@@ -2090,9 +2088,7 @@ activity.  Only run if the buffer is not visible and
 			    rcirc-activity)))
     ;; update the mode-line string
     (unless (equal old-activity rcirc-activity)
-      (rcirc-update-activity-string)))
-
-  (remove-hook 'post-command-hook 'rcirc-window-configuration-change-1))
+      (rcirc-update-activity-string))))
 
 
 ;;; buffer name abbreviation
diff --git a/lisp/window.el b/lisp/window.el
index 751263c9259..424d0525f4e 100644
--- a/lisp/window.el
+++ b/lisp/window.el
@@ -2043,6 +2043,8 @@ doc-string of `window-resizable'."
 ;; Aliases of functions defined in window.c.
 (defalias 'window-height 'window-total-height)
 (defalias 'window-width 'window-body-width)
+(defalias 'window-pixel-width-before-size-change 'window-old-pixel-width)
+(defalias 'window-pixel-height-before-size-change 'window-old-pixel-height)
 
 (defun window-full-height-p (&optional window)
   "Return t if WINDOW is as high as its containing frame.
@@ -2759,8 +2761,7 @@ as small) as possible, but don't signal an error."
 	;; The following routine catches the case where we want to resize
 	;; a minibuffer-only frame.
 	(when (resize-mini-window-internal window)
-	  (window--pixel-to-total frame)
-	  (run-window-configuration-change-hook frame))))))
+	  (window--pixel-to-total frame))))))
 
 (defun window--resize-apply-p (frame &optional horizontal)
   "Return t when a window on FRAME shall be resized vertically.
@@ -2858,9 +2859,7 @@ instead."
 	(window--resize-siblings window delta horizontal ignore))
       (when (window--resize-apply-p frame horizontal)
 	(if (window-resize-apply frame horizontal)
-	    (progn
-	      (window--pixel-to-total frame horizontal)
-	      (run-window-configuration-change-hook frame))
+	    (window--pixel-to-total frame horizontal)
 	  (error "Failed to apply resizing %s" window))))
      (t
       (error "Cannot resize window %s" window)))))
@@ -3579,9 +3578,7 @@ move it as far as possible in the desired direction."
 	;; Don't report an error in the standard case.
 	(when (window--resize-apply-p frame horizontal)
 	  (if (window-resize-apply frame horizontal)
-	      (progn
-		(window--pixel-to-total frame horizontal)
-		(run-window-configuration-change-hook frame))
+	      (window--pixel-to-total frame horizontal)
 	    ;; But do report an error if applying the changes fails.
 	    (error "Failed adjusting window %s" window))))))))
 
@@ -4112,7 +4109,6 @@ that is its frame's root window."
 	  ;; `delete-window-internal' has selected a window that should
 	  ;; not be selected, fix this here.
 	  (other-window -1 frame))
-	(run-window-configuration-change-hook frame)
 	(window--check frame)
 	;; Always return nil.
 	nil))))
@@ -4198,7 +4194,6 @@ any window whose `no-delete-other-windows' parameter is non-nil."
       ;; If WINDOW is the main window of its frame do nothing.
       (unless (eq window main)
 	(delete-other-windows-internal window main)
-	(run-window-configuration-change-hook frame)
 	(window--check frame))
       ;; Always return nil.
       nil)))
@@ -5186,7 +5181,6 @@ frame.  The selected window is not changed by this function."
 	  (unless size
             (window--sanitize-window-sizes horizontal))
 
-	  (run-window-configuration-change-hook frame)
 	  (run-window-scroll-functions new)
 	  (window--check frame)
 	  ;; Always return the new window.
@@ -5417,15 +5411,13 @@ window."
     (balance-windows-1 window)
     (when (window--resize-apply-p frame)
       (window-resize-apply frame)
-      (window--pixel-to-total frame)
-      (run-window-configuration-change-hook frame))
+      (window--pixel-to-total frame))
     ;; Balance horizontally.
     (window--resize-reset (window-frame window) t)
     (balance-windows-1 window t)
     (when (window--resize-apply-p frame t)
       (window-resize-apply frame t)
-      (window--pixel-to-total frame t)
-      (run-window-configuration-change-hook frame))))
+      (window--pixel-to-total frame t))))
 
 (defun window-fixed-size-p (&optional window direction)
   "Return t if WINDOW cannot be resized in DIRECTION.
@@ -9441,15 +9433,7 @@ displaying that processes's buffer."
               (when size
                 (set-process-window-size process (cdr size) (car size))))))))))
 
-;; Remove the following call in Emacs 27, running
-;; 'window-size-change-functions' should suffice.
 (add-hook 'window-configuration-change-hook 'window--adjust-process-windows)
-
-;; Catch any size changes not handled by
-;; 'window-configuration-change-hook' (Bug#32720, "another issue" in
-;; Bug#33230).
-(add-hook 'window-size-change-functions (lambda (_frame)
-                                          (window--adjust-process-windows)))
 
 ;; Some of these are in tutorial--default-keys, so update that if you
 ;; change these.