Fix assignment of a Q(Explicitly)SharedDataPointer included in the data itself

Task-number: related to QTBUG-13079
Reviewed-by: Joao

2 files changed, 54 insertions, 8 deletions

diff --git a/src/corelib/tools/qshareddata.h b/src/corelib/tools/qshareddata.h
index 7e9934d..6483c90 100644
--- a/src/corelib/tools/qshareddata.h
+++ b/src/corelib/tools/qshareddata.h
@@ -95,9 +95,10 @@ public:
         if (o.d != d) {
             if (o.d)
                 o.d->ref.ref();
-            if (d && !d->ref.deref())
-                delete d;
+            T *old = d;
             d = o.d;
+            if (old && !old->ref.deref())
+                delete old;
         }
         return *this;
     }
@@ -105,9 +106,10 @@ public:
         if (o != d) {
             if (o)
                 o->ref.ref();
-            if (d && !d->ref.deref())
-                delete d;
+            T *old = d;
             d = o;
+            if (old && !old->ref.deref())
+                delete old;
         }
         return *this;
     }
@@ -174,9 +176,10 @@ public:
         if (o.d != d) {
             if (o.d)
                 o.d->ref.ref();
-            if (d && !d->ref.deref())
-                delete d;
+            T *old = d;
             d = o.d;
+            if (old && !old->ref.deref())
+                delete old;
         }
         return *this;
     }
@@ -184,9 +187,10 @@ public:
         if (o != d) {
             if (o)
                 o->ref.ref();
-            if (d && !d->ref.deref())
-                delete d;
+            T *old = d;
             d = o;
+            if (old && !old->ref.deref())
+                delete old;
         }
         return *this;
     }
diff --git a/tests/auto/collections/tst_collections.cpp b/tests/auto/collections/tst_collections.cpp
index 8617e02..2dc41aa 100644
--- a/tests/auto/collections/tst_collections.cpp
+++ b/tests/auto/collections/tst_collections.cpp
@@ -3653,6 +3653,44 @@ bool operator==(const QTBUG13079_Node<QSet> &a, const QTBUG13079_Node<QSet> &b)
     return a.s == b.s && a.children == b.children;
 }
 
+template<template<class> class C>
+struct QTBUG13079_NodePtr : QSharedData {
+    C<QTBUG13079_NodePtr> child;
+    QTBUG13079_NodePtr *next;
+    QString s;
+
+    ~QTBUG13079_NodePtr() {
+        child.data(); //play with memory
+        next = 0;
+    }
+};
+template<template<class> class C> void QTBUG13079_collectionInsidePtrImpl()
+{
+    typedef C<QTBUG13079_NodePtr<C> > Ptr;
+    {
+        Ptr nodePtr;
+        nodePtr = Ptr(new QTBUG13079_NodePtr<C>());
+        nodePtr->s = "parent";
+        nodePtr->child = Ptr(new QTBUG13079_NodePtr<C>());
+        nodePtr->child->s = "child";
+        nodePtr = nodePtr->child;
+        QCOMPARE(nodePtr->s, QString::fromLatin1("child"));
+        nodePtr = nodePtr->child;
+        QVERIFY(!nodePtr);
+    }
+    {
+        Ptr nodePtr;
+        nodePtr = Ptr(new QTBUG13079_NodePtr<C>());
+        nodePtr->s = "parent";
+        nodePtr->next = new QTBUG13079_NodePtr<C>();
+        nodePtr->next->s = "next";
+        nodePtr = Ptr(nodePtr->next);
+        QCOMPARE(nodePtr->s, QString::fromLatin1("next"));
+        nodePtr = Ptr(nodePtr->next);
+        QVERIFY(!nodePtr);
+    }
+}
+
 #endif
 
 void tst_Collections::QTBUG13079_collectionInsideCollection()
@@ -3673,6 +3711,10 @@ void tst_Collections::QTBUG13079_collectionInsideCollection()
 
     QTBUG13079_collectionInsideCollectionAssocImpl<QMap>();
     QTBUG13079_collectionInsideCollectionAssocImpl<QHash>();
+
+    QTBUG13079_collectionInsidePtrImpl<QSharedPointer>();
+    QTBUG13079_collectionInsidePtrImpl<QExplicitlySharedDataPointer>();
+    QTBUG13079_collectionInsidePtrImpl<QSharedDataPointer>();
 #endif
 }