From 2c95a4e6b9add636bb2398e8656268c399f97f19 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Ivan=20=C4=8Cuki=C4=87?= <ivan.cukic@kde.org>
Date: Fri, 8 Apr 2016 09:25:02 +0200
Subject: [PATCH] Checking whether m_topLevel is not null before getting its
 property

Summary:
From the rest of this method, it is obvious that m_topLevel can
be null in any part of the method - we are checking against it
being null in a few places in the method - both before and after
the affending lines.

Now, there is one place where the check is not applied, and
potentially calls ->window() on the null pointer.

p.s. If there are more places where kwin does clear_or_something(); return;
it could benefit from introducing on_scope_exit and similar tricks - see
Alexandrescu's 'Declarative control flow' presentation.

Reviewers: graesslin

Reviewed By: graesslin

Subscribers: plasma-devel

Projects: #plasma

Differential Revision: https://phabricator.kde.org/D1346
---
 shadow.cpp | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/shadow.cpp b/shadow.cpp
index 65b4080914..76792ad8bd 100644
--- a/shadow.cpp
+++ b/shadow.cpp
@@ -365,6 +365,10 @@ bool Shadow::updateShadow()
             }
         }
     }
+    if (!m_topLevel) {
+        clear();
+        return false;
+    }
     auto data = Shadow::readX11ShadowProperty(m_topLevel->window());
     if (data.isEmpty()) {
         clear();