[plasma/kwin/Plasma/6.7] src/tiles: tiles: fix null pointer dereference in CustomTile::moveByPixels

Git commit 706e4892c62c2d35636dc9bd2193f453d3224635 by Vlad Zahorodnii, on behalf of zhang shoucheng.
Committed on 06/08/2026 at 08:57.
Pushed by vladz into branch 'Plasma/6.7'.

tiles: fix null pointer dereference in CustomTile::moveByPixels

The root tile has no parent tile, so parentTile() returns nullptr.
When the tiles editor drags the root layout tile, e.g. when no tiling
layout is configured on a desktop, the unchecked dereference of the
parent tile crashes KWin. Null-check parentTile() before using it,
consistent with remove() and nextTileAt().

(cherry picked from commit e1c94f5ef9d866ecf27b2278c9e852da0d20ef56)

M  +2    -1    src/tiles/customtile.cpp

https://invent.kde.org/plasma/kwin/-/commit/706e4892c62c2d35636dc9bd2193f453d3224635

diff --git a/src/tiles/customtile.cpp b/src/tiles/customtile.cpp
index 70fa4485bea..a1ec5bb979d 100644
--- a/src/tiles/customtile.cpp
+++ b/src/tiles/customtile.cpp
@@ -258,7 +258,8 @@ QList<CustomTile *> CustomTile::split(KWin::Tile::LayoutDirection newDirection)
 
 void CustomTile::moveByPixels(const QPointF &delta)
 {
-    if (static_cast<CustomTile *>(parentTile())->layoutDirection() != LayoutDirection::Floating) {
+    const auto parent = static_cast<CustomTile *>(parentTile());
+    if (!parent || parent->layoutDirection() != LayoutDirection::Floating) {
         return;
     }