1 files changed, 25 insertions, 18 deletions

diff --git a/src/corelib/kernel/qobject.cpp b/src/corelib/kernel/qobject.cpp
index a7f48b5c59..35e503d330 100644
--- a/src/corelib/kernel/qobject.cpp
+++ b/src/corelib/kernel/qobject.cpp
@@ -1001,7 +1001,7 @@ QObject::~QObject()
         emit destroyed(this);
     }
 
-    if (d->declarativeData && QAbstractDeclarativeData::destroyed)
+    if (!d->isDeletingChildren && d->declarativeData && QAbstractDeclarativeData::destroyed)
         QAbstractDeclarativeData::destroyed(d->declarativeData, this);
 
     QObjectPrivate::ConnectionData *cd = d->connections.loadRelaxed();
@@ -2155,7 +2155,7 @@ void QObjectPrivate::deleteChildren()
     // delete children objects
     // don't use qDeleteAll as the destructor of the child might
     // delete siblings
-    for (int i = 0; i < children.count(); ++i) {
+    for (int i = 0; i < children.size(); ++i) {
         currentChildBeingDeleted = children.at(i);
         children[i] = nullptr;
         delete currentChildBeingDeleted;
@@ -2303,7 +2303,7 @@ void QObject::removeEventFilter(QObject *obj)
 {
     Q_D(QObject);
     if (d->extraData) {
-        for (int i = 0; i < d->extraData->eventFilters.count(); ++i) {
+        for (int i = 0; i < d->extraData->eventFilters.size(); ++i) {
             if (d->extraData->eventFilters.at(i) == obj)
                 d->extraData->eventFilters[i] = nullptr;
         }
@@ -2625,7 +2625,7 @@ int QObject::receivers(const char *signal) const
         if (!d->isSignalConnected(signal_index))
             return receivers;
 
-        if (d->declarativeData && QAbstractDeclarativeData::receivers) {
+        if (!d->isDeletingChildren && d->declarativeData && QAbstractDeclarativeData::receivers) {
             receivers += QAbstractDeclarativeData::receivers(d->declarativeData, this,
                                                              signal_index);
         }
@@ -2653,13 +2653,15 @@ int QObject::receivers(const char *signal) const
 
     \snippet code/src_corelib_kernel_qobject.cpp 49
 
-    As the code snippet above illustrates, you can use this function
-    to avoid emitting a signal that nobody listens to.
+    As the code snippet above illustrates, you can use this function to avoid
+    expensive initialization or emitting a signal that nobody listens to.
+    However, in a multithreaded application, connections might change after
+    this function returns and before the signal gets emitted.
 
     \warning This function violates the object-oriented principle of
-    modularity. However, it might be useful when you need to perform
-    expensive initialization only if something is connected to a
-    signal.
+    modularity. In particular, this function must not be called from an
+    override of connectNotify() or disconnectNotify(), as those might get
+    called from any thread.
 */
 bool QObject::isSignalConnected(const QMetaMethod &signal) const
 {
@@ -3333,8 +3335,13 @@ bool QObject::disconnect(const QObject *sender, const QMetaMethod &signal,
     signal.
 
     \warning This function is called from the thread which performs the
-    connection, which may be a different thread from the thread in
-    which this object lives.
+    connection, which may be a different thread from the thread in which
+    this object lives. This function may also be called with a QObject internal
+    mutex locked. It is therefore not allowed to re-enter any QObject
+    functions, including isSignalConnected(), from your reimplementation. If
+    you lock a mutex in your reimplementation, make sure that you don't call
+    QObject functions with that mutex held in other places or it will result in
+    a deadlock.
 
     \sa connect(), disconnectNotify()
 */
@@ -3363,12 +3370,12 @@ void QObject::connectNotify(const QMetaMethod &signal)
     expensive resources.
 
     \warning This function is called from the thread which performs the
-    disconnection, which may be a different thread from the thread in
-    which this object lives. This function may also be called with a QObject
-    internal mutex locked. It is therefore not allowed to re-enter any
-    of any QObject functions from your reimplementation and if you lock
-    a mutex in your reimplementation, make sure that you don't call QObject
-    functions with that mutex held in other places or it will result in
+    disconnection, which may be a different thread from the thread in which
+    this object lives. This function may also be called with a QObject internal
+    mutex locked. It is therefore not allowed to re-enter any QObject
+    functions, including isSignalConnected(), from your reimplementation. If
+    you lock a mutex in your reimplementation, make sure that you don't call
+    QObject functions with that mutex held in other places or it will result in
     a deadlock.
 
     \sa disconnect(), connectNotify()
@@ -3684,7 +3691,7 @@ void QMetaObject::connectSlotsByName(QObject *o)
 
         // ...we check each object in our list, ...
         bool foundIt = false;
-        for (int j = 0; j < list.count(); ++j) {
+        for (int j = 0; j < list.size(); ++j) {
             const QObject *co = list.at(j);
             const QByteArray coName = co->objectName().toLatin1();