Fix calling Qt.binding() on bound functions

Calling Qt.binding() on a bound function object is a valid use
case and used to work until Qt 5.8.

The problem was that we optimized the code in QQmlBinding and
QQmlJavascriptExpression to directly work on a QV4::Function,
so this wouldn't work anymore.

To fix this make sure recursive calls to Function.bind() are
unrolled (so that the BoundFunction's target is never a bound
function itself), then add the bound function as an optional
member to the QQmlBinding and use it's bound arguments if
present.

Task-number: QTBUG-61927
Change-Id: I472214ddd82fc2a1212efd9b769861fc43d2ddaf
Reviewed-by: Simon Hausmann <simon.hausmann@qt.io>

1 files changed, 1 insertions, 13 deletions

diff --git a/src/qml/qml/qqmljavascriptexpression.cpp b/src/qml/qml/qqmljavascriptexpression.cpp
index 40cf1417d0..93ec9421ed 100644
--- a/src/qml/qml/qqmljavascriptexpression.cpp
+++ b/src/qml/qml/qqmljavascriptexpression.cpp
@@ -97,8 +97,7 @@ QQmlJavaScriptExpression::QQmlJavaScriptExpression()
       m_context(nullptr),
       m_prevExpression(nullptr),
       m_nextExpression(nullptr),
-      m_v4Function(nullptr),
-      m_sourceLocation(nullptr)
+      m_v4Function(nullptr)
 {
 }
 
@@ -115,8 +114,6 @@ QQmlJavaScriptExpression::~QQmlJavaScriptExpression()
     clearError();
     if (m_scopeObject.isT2()) // notify DeleteWatcher of our deletion.
         m_scopeObject.asT2()->_s = nullptr;
-
-    delete m_sourceLocation;
 }
 
 void QQmlJavaScriptExpression::setNotifyOnValueChanged(bool v)
@@ -137,20 +134,11 @@ void QQmlJavaScriptExpression::resetNotifyOnValueChanged()
 
 QQmlSourceLocation QQmlJavaScriptExpression::sourceLocation() const
 {
-    if (m_sourceLocation)
-        return *m_sourceLocation;
     if (m_v4Function)
         return m_v4Function->sourceLocation();
     return QQmlSourceLocation();
 }
 
-void QQmlJavaScriptExpression::setSourceLocation(const QQmlSourceLocation &location)
-{
-    if (m_sourceLocation)
-        delete m_sourceLocation;
-    m_sourceLocation = new QQmlSourceLocation(location);
-}
-
 void QQmlJavaScriptExpression::setContext(QQmlContextData *context)
 {
     if (m_prevExpression) {