From f0818f6ed8a616dcc94785637039ac21468ef311 Mon Sep 17 00:00:00 2001
From: Christian Ehrlicher <ch.ehrlicher@gmx.de>
Date: Fri, 1 Jan 2021 11:27:10 +0100
Subject: QAbstractButton: don't access nullptr in queryButtonList()

When a button has no parent, QAbstractButtonPrivate::queryButtonList()
unconditionally accessed parent which results in a nullptr access. Did
not crash because qt_qFindChildren_helper checks for nullptr and
therefore could only be found with a sanitizer.

Fixes: QTBUG-83865
Change-Id: I591e546e96acba50770935b9c3baaf08b09b833d
Pick-to: 6.0
Reviewed-by: Samuel Gaist <samuel.gaist@idiap.ch>
---
 src/widgets/widgets/qabstractbutton.cpp | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

(limited to 'src/widgets')

diff --git a/src/widgets/widgets/qabstractbutton.cpp b/src/widgets/widgets/qabstractbutton.cpp
index 727cd66ed4..de6741c030 100644
--- a/src/widgets/widgets/qabstractbutton.cpp
+++ b/src/widgets/widgets/qabstractbutton.cpp
@@ -190,7 +190,9 @@ QList<QAbstractButton *>QAbstractButtonPrivate::queryButtonList() const
         return group->d_func()->buttonList;
 #endif
 
-    QList<QAbstractButton*>candidates = parent->findChildren<QAbstractButton *>();
+    if (!parent)
+        return {};
+    QList<QAbstractButton *> candidates = parent->findChildren<QAbstractButton *>();
     if (autoExclusive) {
         auto isNoMemberOfMyAutoExclusiveGroup = [](QAbstractButton *candidate) {
             return !candidate->autoExclusive()
-- 
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