[mutter] window: Really force update monitor on hot plugs

[Jonas Ådahl <jadahl src gnome org>]

commit fa495286a1037d610051ab49f0aa1e8b20e38066
Author: Olivier Fourdan <ofourdan redhat com>
Date:   Tue Nov 6 13:35:31 2018 +0100

    window: Really force update monitor on hot plugs
    
    Commit 8d3e05305 ("window: Force update monitor on hot plugs") added the
    flag `META_WINDOW_UPDATE_MONITOR_FLAGS_FORCE` passed to
    `update_monitor()` from `update_for_monitors_changed()`.
    
    However, `update_for_monitors_changed()` may choose to call another code
    path to `move_between_rects()` and `meta_window_move_resize_internal()`
    eventually.
    
    As `meta_window_move_resize_internal()` does not use the "force" flag,
    we may still end up in case where the window->monitor is left unchanged.
    
    To avoid that problem, add a new `MetaMoveResizeFlags` that
    `update_for_monitors_changed()` can use to force the monitor update from
    `meta_window_move_resize_internal()`.
    
    Fixes: 8d3e05305 ("window: Force update monitor on hot plugs")
    Closes: https://gitlab.gnome.org/GNOME/mutter/issues/189

 src/core/window-private.h |  1 +
 src/core/window.c         | 16 +++++++++++++---
 2 files changed, 14 insertions(+), 3 deletions(-)
---
diff --git a/src/core/window-private.h b/src/core/window-private.h
index 6fc943f72..4cc05d934 100644
--- a/src/core/window-private.h
+++ b/src/core/window-private.h
@@ -80,6 +80,7 @@ typedef enum
   META_MOVE_RESIZE_UNMAXIMIZE = 1 << 6,
   META_MOVE_RESIZE_FORCE_MOVE = 1 << 7,
   META_MOVE_RESIZE_WAYLAND_STATE_CHANGED = 1 << 8,
+  META_MOVE_RESIZE_FORCE_UPDATE_MONITOR = 1 << 9,
 } MetaMoveResizeFlags;
 
 typedef enum
diff --git a/src/core/window.c b/src/core/window.c
index d00719e23..4d9e51d8c 100644
--- a/src/core/window.c
+++ b/src/core/window.c
@@ -120,6 +120,7 @@ static gboolean queue_calc_showing_func (MetaWindow *window,
                                          void       *data);
 
 static void meta_window_move_between_rects (MetaWindow          *window,
+                                            MetaMoveResizeFlags  move_resize_flags,
                                             const MetaRectangle *old_area,
                                             const MetaRectangle *new_area);
 
@@ -3864,6 +3865,7 @@ meta_window_update_for_monitors_changed (MetaWindow *window)
        * monitors changed and the same index could be refereing
        * to a different monitor. */
       meta_window_move_between_rects (window,
+                                      META_MOVE_RESIZE_FORCE_UPDATE_MONITOR,
                                       &old->rect,
                                       &new->rect);
     }
@@ -4045,6 +4047,8 @@ meta_window_move_resize_internal (MetaWindow          *window,
   update_monitor_flags = META_WINDOW_UPDATE_MONITOR_FLAGS_NONE;
   if (flags & META_MOVE_RESIZE_USER_ACTION)
     update_monitor_flags |= META_WINDOW_UPDATE_MONITOR_FLAGS_USER_OP;
+  if (flags & META_MOVE_RESIZE_FORCE_UPDATE_MONITOR)
+    update_monitor_flags |= META_WINDOW_UPDATE_MONITOR_FLAGS_FORCE;
 
   if (window->monitor)
     {
@@ -4104,6 +4108,7 @@ meta_window_move_frame (MetaWindow *window,
 
 static void
 meta_window_move_between_rects (MetaWindow  *window,
+                                MetaMoveResizeFlags  move_resize_flags,
                                 const MetaRectangle *old_area,
                                 const MetaRectangle *new_area)
 {
@@ -4127,7 +4132,12 @@ meta_window_move_between_rects (MetaWindow  *window,
   window->saved_rect.x = window->unconstrained_rect.x;
   window->saved_rect.y = window->unconstrained_rect.y;
 
-  meta_window_move_resize_now (window);
+  meta_window_move_resize_internal (window,
+                                    move_resize_flags |
+                                    META_MOVE_RESIZE_MOVE_ACTION |
+                                    META_MOVE_RESIZE_RESIZE_ACTION,
+                                    NorthWestGravity,
+                                    window->unconstrained_rect);
 }
 
 /**
@@ -4188,14 +4198,14 @@ meta_window_move_to_monitor (MetaWindow  *window,
       window->unconstrained_rect.height == 0 ||
       !meta_rectangle_overlap (&window->unconstrained_rect, &old_area))
     {
-      meta_window_move_between_rects (window, NULL, &new_area);
+      meta_window_move_between_rects (window, 0, NULL, &new_area);
     }
   else
     {
       if (monitor == window->monitor->number)
         return;
 
-      meta_window_move_between_rects (window, &old_area, &new_area);
+      meta_window_move_between_rects (window, 0, &old_area, &new_area);
     }
 
   window->preferred_output_winsys_id = window->monitor->winsys_id;