From d1210281e41008ce2e3510aa5cfb3ebea1c57734 Mon Sep 17 00:00:00 2001
From: Ihor Dutchak <ihor.youw@gmail.com>
Date: Mon, 17 Apr 2017 00:35:38 +0300
Subject: Fix undefined behavior in QSharedPointer::create()

Initialize a deleter for a new object, created by
QSharedPointer::create(), only after the object is actually
constructed.

[ChangeLog][QtCore][QSharedPointer] Fixed undefined behavior when
creating an object with QSharedPointer::create() and its conscructor
throws an exception.

Task-number: QTBUG-49824
Change-Id: I07f77a78ff468d9b45b8ef133278e8cdd96a0647
Reviewed-by: Olivier Goffart (Woboq GmbH) <ogoffart@woboq.com>
---
 .../tools/qsharedpointer/tst_qsharedpointer.cpp    | 50 ++++++++++++++++++++++
 1 file changed, 50 insertions(+)

(limited to 'tests/auto/corelib/tools')

diff --git a/tests/auto/corelib/tools/qsharedpointer/tst_qsharedpointer.cpp b/tests/auto/corelib/tools/qsharedpointer/tst_qsharedpointer.cpp
index d0a0feb125..7850478602 100644
--- a/tests/auto/corelib/tools/qsharedpointer/tst_qsharedpointer.cpp
+++ b/tests/auto/corelib/tools/qsharedpointer/tst_qsharedpointer.cpp
@@ -97,6 +97,8 @@ private slots:
     void qvariantCast();
     void sharedFromThis();
 
+    void constructorThrow();
+
     void threadStressTest_data();
     void threadStressTest();
     void validConstructs();
@@ -2594,6 +2596,54 @@ void tst_QSharedPointer::sharedFromThis()
     QCOMPARE(Data::destructorCounter, destructions + 6);
 }
 
+#ifndef QT_NO_EXCEPTIONS
+class ThrowData: public Data
+{
+public:
+    static int childDestructorCounter;
+    static int childGenerationCounter;
+
+    ThrowData()
+    {
+        childGenerationCounter++;
+        throw QStringLiteral("Dummy exception");
+    }
+
+    ~ThrowData()
+    {
+        childDestructorCounter++;
+    }
+};
+int ThrowData::childDestructorCounter = 0;
+int ThrowData::childGenerationCounter = 0;
+#endif // !QT_NO_EXCEPTIONS
+
+void tst_QSharedPointer::constructorThrow()
+{
+#ifndef QT_NO_EXCEPTIONS
+    int generation = Data::generationCounter;
+    int destructorCounter = Data::destructorCounter;
+
+    int childGeneration = ThrowData::childGenerationCounter;
+    int childDestructorCounter = ThrowData::childDestructorCounter;
+
+    QSharedPointer<ThrowData> ptr;
+    QVERIFY_EXCEPTION_THROWN(ptr = QSharedPointer<ThrowData>::create(), QString);
+    QVERIFY(ptr.isNull());
+    QCOMPARE(ThrowData::childGenerationCounter, childGeneration + 1);
+    // destructor should never be called, if a constructor throws
+    // an exception
+    QCOMPARE(ThrowData::childDestructorCounter, childDestructorCounter);
+
+    QCOMPARE(Data::generationCounter, generation + 1);
+    // but base class constructor doesn't throw, so base class destructor
+    // should be called
+    QCOMPARE(Data::destructorCounter, destructorCounter + 1);
+#else
+    QSKIP("Needs exceptions");
+#endif // !QT_NO_EXCEPTIONS
+}
+
 namespace ReentrancyWhileDestructing {
     struct IB
     {
-- 
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