Fix broken Maroon game / regression in PropertyChanges {} element

Commit 0aadcf8077840068eb182269e9ed9c31ad12f45e that pre-compiles the
expressions in PropertyChanges {} introduced a regression in where the
evaluation context was incorrect and thus bindings would not be able to
access the correct properties. For example

    PropertyChanges {
        target: someObject
        y: height / 2
    }

Here height should be looked up in the context of "someObject", not of the
PropertyChanges element.

This patch introduces an auto-test that verifies that the lookup context is
correct and fixes the bug by disabling accelerated compile time property
lookups for binding expressions that are requested from a custom parser.

Change-Id: I5cb607d07211b453ddfc9928ccbf5f9ecec85575
Reviewed-by: Lars Knoll <lars.knoll@digia.com>

3 files changed, 16 insertions, 10 deletions

diff --git a/src/qml/qml/qqmlcompiler.cpp b/src/qml/qml/qqmlcompiler.cpp
index 2b925b24ec..1e5f6bfa34 100644
--- a/src/qml/qml/qqmlcompiler.cpp
+++ b/src/qml/qml/qqmlcompiler.cpp
@@ -62,7 +62,6 @@
 #include "qqmlglobal_p.h"
 #include "qqmlbinding_p.h"
 #include "qqmlabstracturlinterceptor_p.h"
-#include "qqmlcodegenerator_p.h"
 
 #include <QDebug>
 #include <QPointF>
@@ -2707,6 +2706,10 @@ int QQmlCompiler::bindingIdentifier(const QString &name, const Variant &value, c
     reference->value = 0;
     reference->bindingContext = ctxt;
     reference->bindingContext.owner++;
+    // Unfortunately this is required for example for PropertyChanges where the bindings
+    // will be executed in the dynamic scope of the target, so we can't resolve any lookups
+    // at run-time.
+    reference->disableLookupAcceleration = true;
 
     const int id = output->customParserBindings.count();
     output->customParserBindings.append(0); // Filled in later.
@@ -3684,9 +3687,12 @@ bool QQmlCompiler::completeComponentBuild()
         }
 
         ComponentCompileState::PerObjectCompileData *cd = &compileState->jsCompileData[b->bindingContext.object];
-        cd->functionsToCompile.append(node);
+        QtQml::CompiledFunctionOrExpression f;
+        f.node = node;
+        f.name = binding.property->name().toString().prepend(QStringLiteral("expression for "));
+        f.disableAcceleratedLookups = binding.disableLookupAcceleration;
+        cd->functionsToCompile.append(f);
         binding.compiledIndex = cd->functionsToCompile.count() - 1;
-        cd->expressionNames.insert(binding.compiledIndex, binding.property->name().toString().prepend(QStringLiteral("expression for ")));
 
         if (componentStats && b->value)
             componentStats->componentStat.scriptBindings.append(b->value->location);
@@ -3719,7 +3725,7 @@ bool QQmlCompiler::completeComponentBuild()
 
             jsCodeGen.beginObjectScope(scopeObject->metatype);
 
-            cd->runtimeFunctionIndices = jsCodeGen.generateJSCodeForFunctionsAndBindings(cd->functionsToCompile, cd->expressionNames);
+            cd->runtimeFunctionIndices = jsCodeGen.generateJSCodeForFunctionsAndBindings(cd->functionsToCompile);
             QList<QQmlError> errors = jsCodeGen.errors();
             if (!errors.isEmpty()) {
                 exceptions << errors;
diff --git a/src/qml/qml/qqmlcompiler_p.h b/src/qml/qml/qqmlcompiler_p.h
index 75f404a7d5..516f6653ca 100644
--- a/src/qml/qml/qqmlcompiler_p.h
+++ b/src/qml/qml/qqmlcompiler_p.h
@@ -62,6 +62,7 @@
 #include "qqmlpropertycache_p.h"
 #include "qqmltypenamecache_p.h"
 #include "qqmltypeloader_p.h"
+#include <private/qqmlcodegenerator_p.h>
 #include "private/qv4identifier_p.h"
 #include <private/qqmljsastfwd_p.h>
 
@@ -231,14 +232,15 @@ namespace QQmlCompilerTypes {
     struct JSBindingReference : public QQmlPool::Class,
                                 public BindingReference
     {
-        JSBindingReference() : nextReference(0) {}
+        JSBindingReference() : disableLookupAcceleration(false), nextReference(0) {}
 
         QQmlScript::Variant expression;
         QQmlScript::Property *property;
         QQmlScript::Value *value;
 
         int compiledIndex : 16;
-        int customParserBindingsIndex : 16;
+        int customParserBindingsIndex : 15;
+        int disableLookupAcceleration: 1;
 
         BindingContext bindingContext;
 
@@ -319,10 +321,9 @@ namespace QQmlCompilerTypes {
         QList<CompiledMetaMethod> compiledMetaMethods;
         struct PerObjectCompileData
         {
-            QList<QQmlJS::AST::Node*> functionsToCompile;
+            QList<QtQml::CompiledFunctionOrExpression> functionsToCompile;
             QVector<int> runtimeFunctionIndices;
             QVector<CompiledMetaMethod> compiledMetaMethods;
-            QHash<int, QString> expressionNames;
         };
         QHash<QQmlScript::Object *, PerObjectCompileData> jsCompileData;
     };
diff --git a/src/qml/qml/qqmltypeloader.cpp b/src/qml/qml/qqmltypeloader.cpp
index 7d377af0f8..c9694da0df 100644
--- a/src/qml/qml/qqmltypeloader.cpp
+++ b/src/qml/qml/qqmltypeloader.cpp
@@ -2372,8 +2372,7 @@ void QQmlTypeData::compile()
         // Compile JS binding expressions and signal handlers
 
         JSCodeGen jsCodeGen(finalUrlString(), parsedQML->code, &parsedQML->jsModule, &parsedQML->jsParserEngine, parsedQML->program, m_compiledData->importCache);
-        QHash<int, QString> expressionNames; // ### TODO
-        const QVector<int> runtimeFunctionIndices = jsCodeGen.generateJSCodeForFunctionsAndBindings(parsedQML->functions, expressionNames);
+        const QVector<int> runtimeFunctionIndices = jsCodeGen.generateJSCodeForFunctionsAndBindings(parsedQML->functions);
 
         QV4::ExecutionEngine *v4 = QV8Engine::getV4(m_typeLoader->engine());