From 70abc0b2eebc777309d372203df5ca1e785402d8 Mon Sep 17 00:00:00 2001
From: Szabolcs David <davidsz@inf.u-szeged.hu>
Date: Mon, 20 Sep 2021 09:29:30 +0200
Subject: Fix WebChannel when JavaScript is disabled

WebChannel was not working in ApplicationWorld with JavaScript disabled
in MainWorld, because WebChannelIPCTransport::DidClearWindowObject() is
called only when the window object was cleared in the main world. Moving
the WebChannelTransport installation logic to DidCreateScriptContext()
works in other worlds, so fixes the problem.

Task-number: QTBUG-88875
Pick-to: 6.2
Change-Id: Ia75613b66a1e049f617f0664684b153b6875e9de
Reviewed-by: Allan Sandfeld Jensen <allan.jensen@qt.io>
---
 src/core/renderer/web_channel_ipc_transport.cpp    | 16 +++++------
 src/core/renderer/web_channel_ipc_transport.h      |  2 +-
 .../qwebenginescript/tst_qwebenginescript.cpp      | 31 ++++++++++++++++++++++
 3 files changed, 40 insertions(+), 9 deletions(-)

diff --git a/src/core/renderer/web_channel_ipc_transport.cpp b/src/core/renderer/web_channel_ipc_transport.cpp
index fff3eb70f..8525c3619 100644
--- a/src/core/renderer/web_channel_ipc_transport.cpp
+++ b/src/core/renderer/web_channel_ipc_transport.cpp
@@ -259,21 +259,21 @@ void WebChannelIPCTransport::DispatchWebChannelMessage(const std::vector<uint8_t
     frame->CallFunctionEvenIfScriptDisabled(callback, webChannelObject, 1, argv);
 }
 
-void WebChannelIPCTransport::WillReleaseScriptContext(v8::Local<v8::Context> context, int worldId)
-{
-    if (static_cast<uint>(worldId) == m_worldId)
-        m_canUseContext = false;
-}
-
-void WebChannelIPCTransport::DidClearWindowObject()
+void WebChannelIPCTransport::DidCreateScriptContext(v8::Local<v8::Context> context, int32_t worldId)
 {
-    if (!m_canUseContext) {
+    if (static_cast<uint>(worldId) == m_worldId && !m_canUseContext) {
         m_canUseContext = true;
         if (m_worldInitialized)
             WebChannelTransport::Install(render_frame()->GetWebFrame(), m_worldId);
     }
 }
 
+void WebChannelIPCTransport::WillReleaseScriptContext(v8::Local<v8::Context> context, int worldId)
+{
+    if (static_cast<uint>(worldId) == m_worldId)
+        m_canUseContext = false;
+}
+
 void WebChannelIPCTransport::OnDestruct()
 {
     delete this;
diff --git a/src/core/renderer/web_channel_ipc_transport.h b/src/core/renderer/web_channel_ipc_transport.h
index 276167a67..f048a26d8 100644
--- a/src/core/renderer/web_channel_ipc_transport.h
+++ b/src/core/renderer/web_channel_ipc_transport.h
@@ -64,8 +64,8 @@ private:
     void DispatchWebChannelMessage(const std::vector<uint8_t> &json, uint32_t worldId) override;
 
     // RenderFrameObserver
+    void DidCreateScriptContext(v8::Local<v8::Context> context, int32_t worldId) override;
     void WillReleaseScriptContext(v8::Local<v8::Context> context, int worldId) override;
-    void DidClearWindowObject() override;
     void OnDestruct() override;
     void BindReceiver(mojo::PendingAssociatedReceiver<qtwebchannel::mojom::WebChannelTransportRender> receiver);
 
diff --git a/tests/auto/widgets/qwebenginescript/tst_qwebenginescript.cpp b/tests/auto/widgets/qwebenginescript/tst_qwebenginescript.cpp
index ca2f0cab9..5df9f035f 100644
--- a/tests/auto/widgets/qwebenginescript/tst_qwebenginescript.cpp
+++ b/tests/auto/widgets/qwebenginescript/tst_qwebenginescript.cpp
@@ -70,6 +70,7 @@ private Q_SLOTS:
     void webChannelWithExistingQtObject();
     void navigation();
     void webChannelWithBadString();
+    void webChannelWithJavaScriptDisabled();
 #endif
     void noTransportWithoutWebChannel();
     void scriptsInNestedIframes();
@@ -592,6 +593,36 @@ void tst_QWebEngineScript::webChannelWithBadString()
     QChar data(0xd800);
     QCOMPARE(host.text(), data);
 }
+
+void tst_QWebEngineScript::webChannelWithJavaScriptDisabled()
+{
+    QWebEnginePage page;
+    QSignalSpy spyFinished(&page, &QWebEnginePage::loadFinished);
+    // JavaScript disabled in main world
+    page.settings()->setAttribute(QWebEngineSettings::JavascriptEnabled, false);
+
+    TestObject testObject;
+    QScopedPointer<QWebChannel> channel(new QWebChannel(this));
+    channel->registerObject(QStringLiteral("object"), &testObject);
+    page.setWebChannel(channel.data(), QWebEngineScript::ApplicationWorld);
+
+    QWebEngineScript script = webChannelScript();
+    script.setWorldId(QWebEngineScript::ApplicationWorld);
+    page.scripts().insert(script);
+
+    page.setHtml(QStringLiteral("<html><body></body></html>"));
+    QVERIFY(spyFinished.wait());
+
+    QSignalSpy spyTextChanged(&testObject, &TestObject::textChanged);
+    page.runJavaScript(QLatin1String(
+                                "new QWebChannel(qt.webChannelTransport,"
+                                "  function(channel) {"
+                                "    channel.objects.object.text = 'test';"
+                                "  }"
+                                ");"), QWebEngineScript::ApplicationWorld);
+    QVERIFY(spyTextChanged.wait());
+    QCOMPARE(testObject.text(), QStringLiteral("test"));
+}
 #endif
 
 void tst_QWebEngineScript::matchQrcUrl()
-- 
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