[QML] evaluateJavaScript should preserve null values in result

We should not convert null to undefined when returning JS values from JSC
to QJSEngine.

Change-Id: I20f5638fe9104341e1a0878fdbdbc49e5fa8d2e1
Reviewed-by: Simon Hausmann <simon.hausmann@qt.io>

2 files changed, 41 insertions, 0 deletions

diff --git a/Source/WebKit2/UIProcess/API/qt/qquickwebview.cpp b/Source/WebKit2/UIProcess/API/qt/qquickwebview.cpp
index bc2d5d21c..5300a40ff 100644
--- a/Source/WebKit2/UIProcess/API/qt/qquickwebview.cpp
+++ b/Source/WebKit2/UIProcess/API/qt/qquickwebview.cpp
@@ -131,6 +131,11 @@ static QJSValue buildQJSValue(QJSEngine* engine, JSGlobalContextRef context, JSV
         return var;
 
     switch (JSValueGetType(context, value)) {
+    case kJSTypeUndefined:
+        break;
+    case kJSTypeNull:
+        var = QJSValue(QJSValue::NullValue);
+        break;
     case kJSTypeBoolean:
         var = QJSValue(JSValueToBoolean(context, value));
         break;
diff --git a/Source/WebKit2/UIProcess/API/qt/tests/qmltests/WebView/tst_evaluateJavaScript.qml b/Source/WebKit2/UIProcess/API/qt/tests/qmltests/WebView/tst_evaluateJavaScript.qml
index ea903f328..b4576af36 100644
--- a/Source/WebKit2/UIProcess/API/qt/tests/qmltests/WebView/tst_evaluateJavaScript.qml
+++ b/Source/WebKit2/UIProcess/API/qt/tests/qmltests/WebView/tst_evaluateJavaScript.qml
@@ -81,6 +81,42 @@ Item {
                 '{"level":"1","child":{"level":2}}')
         }
 
+        function test_undefinedValue() {
+            resultSpy.clear()
+            webView.url = "about:blank"
+            verify(webView.waitForLoadSucceeded())
+
+            webView.experimental.evaluateJavaScript(
+                "(function() { })()",
+
+                function(result) {
+                    webView.lastResult = result
+                })
+
+            resultSpy.wait()
+            verify(typeof webView.lastResult === "undefined")
+            compare(webView.lastResult, undefined)
+        }
+
+        function test_nullValue() {
+            resultSpy.clear()
+
+            webView.url = "about:blank"
+            verify(webView.waitForLoadSucceeded())
+
+            webView.experimental.evaluateJavaScript(
+                "(function() { return { value: null } })()",
+
+                function(result) {
+                    webView.lastResult = result
+                })
+
+            resultSpy.wait()
+            verify(typeof webView.lastResult === "object")
+            verify(typeof webView.lastResult.value === "object")
+            compare(webView.lastResult.value, null)
+        }
+
         function test_booleanValue() {
             resultSpy.clear()
             webView.url = "about:blank"