QML Tooling: Prevent property capture while collecting data

We don't want additional connections to be formed as result of reporting
data to the debugger.

Task-number: QTBUG-70989
Change-Id: I78b038a159addac43a8661e402a70e5b14fb222b
Reviewed-by: Simon Hausmann <simon.hausmann@qt.io>

2 files changed, 29 insertions, 1 deletions

diff --git a/src/plugins/qmltooling/qmldbg_debugger/qv4datacollector.cpp b/src/plugins/qmltooling/qmldbg_debugger/qv4datacollector.cpp
index 73e9a1b219..8c92b4b170 100644
--- a/src/plugins/qmltooling/qmldbg_debugger/qv4datacollector.cpp
+++ b/src/plugins/qmltooling/qmldbg_debugger/qv4datacollector.cpp
@@ -339,8 +339,36 @@ QV4::ReturnedValue QV4DataCollector::getValue(Ref ref)
     return array->get(ref, nullptr);
 }
 
+class CapturePreventer
+{
+public:
+    CapturePreventer(QV4::ExecutionEngine *engine)
+    {
+        if (QQmlEngine *e = engine->qmlEngine()) {
+            m_engine = QQmlEnginePrivate::get(e);
+            m_capture = m_engine->propertyCapture;
+            m_engine->propertyCapture = nullptr;
+        }
+    }
+
+    ~CapturePreventer()
+    {
+        if (m_engine && m_capture) {
+            Q_ASSERT(!m_engine->propertyCapture);
+            m_engine->propertyCapture = m_capture;
+        }
+    }
+
+private:
+    QQmlEnginePrivate *m_engine = nullptr;
+    QQmlPropertyCapture *m_capture = nullptr;
+};
+
 QJsonArray QV4DataCollector::collectProperties(const QV4::Object *object)
 {
+    CapturePreventer capturePreventer(engine());
+    Q_UNUSED(capturePreventer);
+
     QJsonArray res;
 
     QV4::Scope scope(engine());
diff --git a/tests/auto/qml/debugger/qqmldebugjs/tst_qqmldebugjs.cpp b/tests/auto/qml/debugger/qqmldebugjs/tst_qqmldebugjs.cpp
index 2e2fda6746..941303d3ef 100644
--- a/tests/auto/qml/debugger/qqmldebugjs/tst_qqmldebugjs.cpp
+++ b/tests/auto/qml/debugger/qqmldebugjs/tst_qqmldebugjs.cpp
@@ -1638,7 +1638,7 @@ void tst_QQmlDebugJS::breakOnAnchor()
     QTRY_COMPARE(m_process->state(), QProcess::NotRunning);
     QCOMPARE(m_process->exitStatus(), QProcess::NormalExit);
 
-    QCOMPARE(breaks, 19);
+    QCOMPARE(breaks, 2);
 }
 
 QList<QQmlDebugClient *> tst_QQmlDebugJS::createClients()