From 49722de99527a97373df517dcb457f3170693a4f Mon Sep 17 00:00:00 2001
From: Thiago Macieira <thiago.macieira@intel.com>
Date: Fri, 11 Feb 2022 08:33:59 -0800
Subject: [PATCH] QWeakPointer: befriend other QWeakPointers

Commit c677b3b8afcdc1d7b57353826cc01f378cd25e99 added move constructors,
which introduced the issue.

Pick-to: 6.2 6.3
Fixes: QTBUG-100795
Change-Id: I74249c52dc02478ba93cfffd16d2c879b923e352
Reviewed-by: Allan Sandfeld Jensen <allan.jensen@qt.io>
---
 src/corelib/tools/qsharedpointer_impl.h       |  3 +-
 .../qsharedpointer/tst_qsharedpointer.cpp     | 55 ++++++++++++++++++-
 2 files changed, 54 insertions(+), 4 deletions(-)

diff --git a/src/corelib/tools/qsharedpointer_impl.h b/src/corelib/tools/qsharedpointer_impl.h
index b29de5f79a9..1b982c0cf90 100644
--- a/src/corelib/tools/qsharedpointer_impl.h
+++ b/src/corelib/tools/qsharedpointer_impl.h
@@ -1,7 +1,7 @@
 /****************************************************************************
 **
 ** Copyright (C) 2021 The Qt Company Ltd.
-** Copyright (C) 2020 Intel Corporation.
+** Copyright (C) 2022 Intel Corporation.
 ** Copyright (C) 2019 Klarälvdalens Datakonsult AB.
 ** Contact: https://www.qt.io/licensing/
 **
@@ -686,6 +686,7 @@ public:
 private:
     friend struct QtPrivate::EnableInternalData;
     template <class X> friend class QSharedPointer;
+    template <class X> friend class QWeakPointer;
     template <class X> friend class QPointer;
 
     template <class X>
diff --git a/tests/auto/corelib/tools/qsharedpointer/tst_qsharedpointer.cpp b/tests/auto/corelib/tools/qsharedpointer/tst_qsharedpointer.cpp
index d526314d41f..5cba44dfb11 100644
--- a/tests/auto/corelib/tools/qsharedpointer/tst_qsharedpointer.cpp
+++ b/tests/auto/corelib/tools/qsharedpointer/tst_qsharedpointer.cpp
@@ -1,8 +1,8 @@
 /****************************************************************************
 **
-** Copyright (C) 2019 The Qt Company Ltd.
-** Copyright (C) 2020 Intel Corporation.
-** Copyright (C) 2019 Klarälvdalens Datakonsult AB.
+** Copyright (C) 2021 The Qt Company Ltd.
+** Copyright (C) 2022 Intel Corporation.
+** Copyright (C) 2021 Klarälvdalens Datakonsult AB.
 ** Contact: https://www.qt.io/licensing/
 **
 ** This file is part of the test suite of the Qt Toolkit.
@@ -795,9 +795,14 @@ public:
 void tst_QSharedPointer::downCast()
 {
     {
+        // copy construction
         QSharedPointer<DerivedData> ptr = QSharedPointer<DerivedData>(new DerivedData);
+        QSharedPointer<DerivedData> copy = ptr;
         QSharedPointer<Data> baseptr = qSharedPointerCast<Data>(ptr);
         QSharedPointer<Data> other;
+        QWeakPointer<DerivedData> weak = ptr;
+        QWeakPointer<Data> baseweak = qSharedPointerCast<Data>(ptr);
+        QWeakPointer<Data> baseweak2 = qSharedPointerCast<Data>(weak);
 
         QVERIFY(ptr == baseptr);
         QVERIFY(baseptr == ptr);
@@ -808,11 +813,55 @@ void tst_QSharedPointer::downCast()
         QVERIFY(other != ptr);
         QVERIFY(! (ptr == other));
         QVERIFY(! (other == ptr));
+
+        // copy assignments
+        baseptr = qSharedPointerCast<Data>(ptr);
+        baseweak = qSharedPointerCast<Data>(ptr);
+        baseweak2 = baseweak;
+
+        // move assignments (these don't actually move)
+        baseptr = qSharedPointerCast<Data>(std::move(ptr));
+        ptr = copy;
+        baseweak = qSharedPointerCast<Data>(std::move(ptr));
+        ptr = copy;
+        baseweak2 = qSharedPointerCast<Data>(std::move(baseweak));
+
+        // move construction (these don't actually move)
+        ptr = copy;
+        QSharedPointer<Data> ptr3(qSharedPointerCast<Data>(std::move(ptr)));
+        ptr = copy;
+        QWeakPointer<Data> baseweak3(qSharedPointerCast<Data>(std::move(ptr)));
+        ptr = copy;
+        QWeakPointer<Data> baseweak4(qSharedPointerCast<Data>(std::move(weak)));
     }
 
     {
+        // copy construction
         QSharedPointer<DerivedData> ptr = QSharedPointer<DerivedData>(new DerivedData);
+        QSharedPointer<DerivedData> copy = ptr;
         QSharedPointer<Data> baseptr = ptr;
+        QWeakPointer<DerivedData> weak = ptr;
+        QWeakPointer<Data> baseweak = ptr;
+        QWeakPointer<Data> baseweak2 = weak;
+
+        // copy assignments
+        baseptr = ptr;
+        baseweak = ptr;
+        baseweak2 = weak;
+
+        // move assignments (only the QSharedPointer-QSharedPointer actually moves)
+        baseweak = std::move(ptr);
+        baseweak2 = std::move(weak);
+        ptr = copy;
+        baseptr = std::move(ptr);
+
+        // move construction (only the QSharedPointer-QSharedPointer actually moves)
+        ptr = copy;
+        QWeakPointer<Data> baseweak3(std::move(ptr));
+        ptr = copy;
+        QWeakPointer<Data> baseweak4(std::move(weak));
+        ptr = copy;
+        QSharedPointer<Data> baseptr2(std::move(ptr));
     }
 
     int destructorCount;