From cae90bb035e6170a9beb38545cf60e31af612804 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Thomas=20L=C3=BCbking?= <thomas.luebking@gmail.com>
Date: Mon, 21 Dec 2015 00:18:00 +0100
Subject: [PATCH] catch nullptr effects when deleting shadows

the shadow can be deleted deferred from an update
there's a slight chance, to be eg. triggered by clients
blocking compositing, that the compositor is suspended in the same
cycle and the effects pointer (and scene and context) thus gone

CCBUG: 356938
FIXED-IN: 5.6
REVIEW: 126441
---
 scene_opengl.cpp | 8 +++++---
 1 file changed, 5 insertions(+), 3 deletions(-)

diff --git a/scene_opengl.cpp b/scene_opengl.cpp
index 85a3838d93..c81c2b8905 100644
--- a/scene_opengl.cpp
+++ b/scene_opengl.cpp
@@ -2195,9 +2195,11 @@ SceneOpenGLShadow::SceneOpenGLShadow(Toplevel *toplevel)
 
 SceneOpenGLShadow::~SceneOpenGLShadow()
 {
-    effects->makeOpenGLContextCurrent();
-    DecorationShadowTextureCache::instance().unregister(this);
-    m_texture.reset();
+    if (effects) {
+        effects->makeOpenGLContextCurrent();
+        DecorationShadowTextureCache::instance().unregister(this);
+        m_texture.reset();
+    }
 }
 
 void SceneOpenGLShadow::buildQuads()