Expose let/const variables from imported JS scripts

This patch allows QML to access let/const variables defined in JS files.

Detailed changes:

  - The recently added ContextType::ScriptImportedByQML is changed to avoid
    creating Push/PopScriptContext instructions, similar to
    ContextType::ESModule.

  - QV4::Module is changed to also work with CompilationUnits which are not
    ESModules. In this case QV4::Module will behave as if all lexically scoped
    variables were exported.

  - CompilationUnit is changed to support instantiating and evaluating
    QV4::Modules for non-ESModules as well.

  - QQmlTypeLoader is changed to always create QV4::Modules for evaluating
    scripts. For the non-ESModule case, the QV4::Module is evaluated inside a
    QV4::QmlContext, as before.

  - A pointer to the QV4::Module is added to QV4::QQmlContextWrapper, and used
    in virtualGet to access the let/const variables in the CallContext. Access
    is read-only.

Fixes: QTBUG-69408
Change-Id: I6f299363fdf5e1c5a4a0f1d9e655b4dc5112dd00
Reviewed-by: Simon Hausmann <simon.hausmann@qt.io>

1 files changed, 14 insertions, 1 deletions

diff --git a/src/qml/jsruntime/qv4qmlcontext.cpp b/src/qml/jsruntime/qv4qmlcontext.cpp
index cc0b0feeee..88b0822f42 100644
--- a/src/qml/jsruntime/qv4qmlcontext.cpp
+++ b/src/qml/jsruntime/qv4qmlcontext.cpp
@@ -54,6 +54,7 @@
 #include <private/qqmljavascriptexpression_p.h>
 #include <private/qjsvalue_p.h>
 #include <private/qv4qobjectwrapper_p.h>
+#include <private/qv4module_p.h>
 
 QT_BEGIN_NAMESPACE
 
@@ -87,8 +88,20 @@ ReturnedValue QQmlContextWrapper::virtualGet(const Managed *m, PropertyKey id, c
     QV4::ExecutionEngine *v4 = resource->engine();
     QV4::Scope scope(v4);
 
-    if (v4->callingQmlContext() != *resource->d()->context)
+    if (v4->callingQmlContext() != *resource->d()->context) {
+        if (resource->d()->module) {
+            Scoped<Module> module(scope, resource->d()->module);
+            bool hasProp = false;
+            ScopedValue value(scope, module->get(id, receiver, &hasProp));
+            if (hasProp) {
+                if (hasProperty)
+                    *hasProperty = hasProp;
+                return value->asReturnedValue();
+            }
+        }
+
         return Object::virtualGet(m, id, receiver, hasProperty);
+    }
 
     bool hasProp = false;
     ScopedValue result(scope, Object::virtualGet(m, id, receiver, &hasProp));