From 22416ecaaf58619c716229b71cdca558fda0a861 Mon Sep 17 00:00:00 2001
From: Zhang Yu <zhangyub@uniontech.com>
Date: Wed, 30 Dec 2020 10:57:09 +0800
Subject: [PATCH] Fix QMultiHash::equal_range crashes

QMultiHash::equal_range crashes when called in a const member function.
The Data `d` is a NULL pointer when calling equal_range()
before inserting data into an empty QMultiHash.
Then calling`d->find` crashes.

Fixes: QTBUG-89687
Pick-to: 6.0
Change-Id: I10c3d196cbc72aed8c8c922ef16534bba51037b7
Reviewed-by: Lars Knoll <lars.knoll@qt.io>
---
 src/corelib/tools/qhash.h                    | 3 +++
 tests/auto/corelib/tools/qhash/tst_qhash.cpp | 7 +++++++
 2 files changed, 10 insertions(+)

diff --git a/src/corelib/tools/qhash.h b/src/corelib/tools/qhash.h
index 4b4235aa99..b3c389903a 100644
--- a/src/corelib/tools/qhash.h
+++ b/src/corelib/tools/qhash.h
@@ -1901,6 +1901,9 @@ public:
 
     QPair<const_iterator, const_iterator> equal_range(const Key &key) const noexcept
     {
+        if (!d)
+            return qMakePair(end(), end());
+
         auto it = d->find(key);
         if (it.isUnused())
             return qMakePair(end(), end());
diff --git a/tests/auto/corelib/tools/qhash/tst_qhash.cpp b/tests/auto/corelib/tools/qhash/tst_qhash.cpp
index a922ee55fe..014617f8d4 100644
--- a/tests/auto/corelib/tools/qhash/tst_qhash.cpp
+++ b/tests/auto/corelib/tools/qhash/tst_qhash.cpp
@@ -1735,6 +1735,13 @@ void tst_QHash::equal_range()
         QVERIFY(p2.first == cm1.cbegin() || p2.second == cm1.cend());
     }
 
+    {
+        const QMultiHash<int, int> cm2;
+        auto p1 = cm2.equal_range(0);
+        QVERIFY(p1.first == cm2.end());
+        QVERIFY(p1.second == cm2.end());
+    }
+
     QMultiHash<int, int> h2;
     for (int i = 0; i < 8; ++i)
         for (int j = 0; j < 8; ++j)