From dc48e368fe6973d4fd6170735676aff9085c6105 Mon Sep 17 00:00:00 2001
From: Ivan Solovev <ivan.solovev@qt.io>
Date: Wed, 7 Jul 2021 14:51:36 +0200
Subject: QMultiHash::find - prevent detaching shared null

Do not detach when find(key, value) is called on an empty QMultiHash.

As a drive-by: fix return value for QMultiHash::remove() in case of
empty QMultiHash.

Task-number: QTBUG-91736
Change-Id: I1e32f359e7ee9ce8403dae79d02e0b88a20ec4a5
Reviewed-by: Edward Welbourne <edward.welbourne@qt.io>
Reviewed-by: Lars Knoll <lars.knoll@qt.io>
(cherry picked from commit 82499f81478032911d8f788aa28e8d780b31c973)
Reviewed-by: Qt Cherry-pick Bot <cherrypick_bot@qt-project.org>
---
 tests/auto/corelib/tools/qhash/tst_qhash.cpp | 15 +++++++++++++++
 1 file changed, 15 insertions(+)

(limited to 'tests')

diff --git a/tests/auto/corelib/tools/qhash/tst_qhash.cpp b/tests/auto/corelib/tools/qhash/tst_qhash.cpp
index 6ad7d15c77..375f9048c0 100644
--- a/tests/auto/corelib/tools/qhash/tst_qhash.cpp
+++ b/tests/auto/corelib/tools/qhash/tst_qhash.cpp
@@ -668,12 +668,17 @@ void tst_QHash::empty()
 //copied from tst_QMap
 void tst_QHash::find()
 {
+    const QHash<int, QString> constEmptyHash;
+    QVERIFY(constEmptyHash.find(1) == constEmptyHash.end());
+    QVERIFY(!constEmptyHash.isDetached());
+
     QHash<int, QString> map1;
     QString testString="Teststring %0";
     QString compareString;
     int i,count=0;
 
     QVERIFY(map1.find(1) == map1.end());
+    QVERIFY(!map1.isDetached());
 
     map1.insert(1,"Mensch");
     map1.insert(1,"Mayer");
@@ -682,6 +687,16 @@ void tst_QHash::find()
     QCOMPARE(map1.find(1).value(), QLatin1String("Mayer"));
     QCOMPARE(map1.find(2).value(), QLatin1String("Hej"));
 
+    const QMultiHash<int, QString> constEmptyMultiHash;
+    QVERIFY(constEmptyMultiHash.find(1) == constEmptyMultiHash.cend());
+    QVERIFY(constEmptyMultiHash.find(1, "value") == constEmptyMultiHash.cend());
+    QVERIFY(!constEmptyMultiHash.isDetached());
+
+    QMultiHash<int, QString> emptyMultiHash;
+    QVERIFY(emptyMultiHash.find(1) == emptyMultiHash.end());
+    QVERIFY(emptyMultiHash.find(1, "value") == emptyMultiHash.end());
+    QVERIFY(!emptyMultiHash.isDetached());
+
     QMultiHash<int, QString> multiMap(map1);
     for (i = 3; i < 10; ++i) {
         compareString = testString.arg(i);
-- 
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