Avoid side effects when en exception has been thrown.

We don't want to check for exceptions after every single
line on our runtime methods. A better way to handle this
is to add the check in all methods that have direct side
effects (as e.g. writing to a property of the JS stack).

We also need to return whereever we throw an exception.
To simplify the code, ExecutionContext::throwXxx methods now
return a ReturnedValue (always undefined) for convenience.

Change-Id: Ide6c804f819c731a3f14c6c43121d08029c9fb90
Reviewed-by: Simon Hausmann <simon.hausmann@digia.com>

1 files changed, 3 insertions, 3 deletions

diff --git a/src/qml/jsruntime/qv4sequenceobject.cpp b/src/qml/jsruntime/qv4sequenceobject.cpp
index 320646805b..f6feb2f170 100644
--- a/src/qml/jsruntime/qv4sequenceobject.cpp
+++ b/src/qml/jsruntime/qv4sequenceobject.cpp
@@ -400,7 +400,7 @@ public:
         QV4::Scope scope(ctx);
         QV4::Scoped<QQmlSequence<Container> > This(scope, ctx->callData->thisObject.as<QQmlSequence<Container> >());
         if (!This)
-            ctx->throwTypeError();
+            return ctx->throwTypeError();
 
         if (This->m_isReference) {
             if (!This->m_object)
@@ -415,7 +415,7 @@ public:
         QV4::Scope scope(ctx);
         QV4::Scoped<QQmlSequence<Container> > This(scope, ctx->callData->thisObject.as<QQmlSequence<Container> >());
         if (!This)
-            ctx->throwTypeError();
+            return ctx->throwTypeError();
 
         quint32 newLength = ctx->callData->args[0].toUInt32();
         /* Qt containers have int (rather than uint) allowable indexes. */
@@ -553,7 +553,7 @@ QV4::ReturnedValue SequencePrototype::method_sort(QV4::SimpleCallContext *ctx)
     QV4::Scope scope(ctx);
     QV4::ScopedObject o(scope, ctx->callData->thisObject);
     if (!o || !o->isListType())
-        ctx->throwTypeError();
+        return ctx->throwTypeError();
 
     if (ctx->callData->argc >= 2)
         return o.asReturnedValue();