From 341654213bfd02a448490212e3b9b0d2027dfd2f Mon Sep 17 00:00:00 2001
From: Andrei Golubev <andrei.golubev@qt.io>
Date: Thu, 11 Mar 2021 10:01:04 +0100
Subject: Fix QMultiHash::count(key) crash

As QMultiHash uses a pointer for the data, nullptr dereference is a
thing, so check for valid d before doing anything in count()

Fixes: QTBUG-91704
Change-Id: Ia20440cd7bdc03cb09c77f796fb9c5b52765eac5
Reviewed-by: Lars Knoll <lars.knoll@qt.io>
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>
(cherry picked from commit f226854d256a382a5cc7ff08b10a0d27fbefb0fe)
Reviewed-by: Fabian Kosmale <fabian.kosmale@qt.io>
---
 tests/auto/corelib/tools/qhash/tst_qhash.cpp | 15 +++++++++++++++
 1 file changed, 15 insertions(+)

(limited to 'tests/auto/corelib/tools/qhash/tst_qhash.cpp')

diff --git a/tests/auto/corelib/tools/qhash/tst_qhash.cpp b/tests/auto/corelib/tools/qhash/tst_qhash.cpp
index 5389758b5f..0c3253784e 100644
--- a/tests/auto/corelib/tools/qhash/tst_qhash.cpp
+++ b/tests/auto/corelib/tools/qhash/tst_qhash.cpp
@@ -76,6 +76,8 @@ private slots:
 
     void badHashFunction();
     void hashOfHash();
+
+    void countInEmptyHash();
 };
 
 struct IdentityTracker {
@@ -1890,5 +1892,18 @@ void tst_QHash::hashOfHash()
     (void)qHash(multiHash);
 }
 
+void tst_QHash::countInEmptyHash()
+{
+    {
+        QHash<int, int> hash;
+        QCOMPARE(hash.count(42), 0);
+    }
+
+    {
+        QMultiHash<int, int> hash;
+        QCOMPARE(hash.count(42), 0);
+    }
+}
+
 QTEST_APPLESS_MAIN(tst_QHash)
 #include "tst_qhash.moc"
-- 
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