bug#69093: window-state-put doesn't update current buffer

[Juri Linkov]

>> Martin, could you help to understand what is missing in
>> 'window-state-put' that it doesn't set the current buffer
>> correctly like 'set-window-configuration' does.
>
> The "current buffer" is not part of the state of a window.  It is part
> of a more global state.  Have a look at frameset.el which does at some
> time "Restore selected frame, buffer and point."
>
> As for what 'set-window-configuration' additionally does, have a look at
> 'current-window-configuration' where you can see that besides
>
>   XSETBUFFER (data->f_current_buffer, current_buffer);
>
> it also saves the selected frame, scroll and selected windows of that
> frame's minibuffer or the frame that should receive input focus.

Thanks for explanations.  I see this line in 'set-window-configuration':

      Fset_buffer (new_current_buffer);

Do you think this is the right fix?

diff --git a/lisp/window.el b/lisp/window.el
index 6df20353b5e..34e6c5d4a4f 100644
--- a/lisp/window.el
+++ b/lisp/window.el
@@ -6498,7 +6503,8 @@ window-state-put
          (when (and (window-valid-p window)
                      (eq (window-deletable-p window) t))
            (delete-window window))))
-      (window--check frame))))
+      (window--check frame)
+      (set-buffer (window-buffer)))))
 
 (defun window-state-buffers (state)
   "Return all buffers saved to the given window state STATE."