Protect write accesses to objects

Don't write to objects if we have a pending exception to
avoid any side effects.

Change-Id: I9f93a9195a652dbae7033cc6ebb355d5d86e9b5e
Reviewed-by: Simon Hausmann <simon.hausmann@digia.com>

1 files changed, 7 insertions, 1 deletions

diff --git a/src/qml/jsruntime/qv4engine.cpp b/src/qml/jsruntime/qv4engine.cpp
index cf39d7df4f..bb11011669 100644
--- a/src/qml/jsruntime/qv4engine.cpp
+++ b/src/qml/jsruntime/qv4engine.cpp
@@ -808,7 +808,13 @@ QmlExtensions *ExecutionEngine::qmlExtensions()
 
 ReturnedValue ExecutionEngine::throwException(const ValueRef value)
 {
-//    Q_ASSERT(!hasException);
+    // we can get in here with an exception already set, as the runtime
+    // doesn't check after every operation that can throw.
+    // in this case preserve the first exception to give correct error
+    // information
+    if (hasException)
+        return Encode::undefined();
+
     hasException = true;
     exceptionValue = value;
     QV4::Scope scope(this);