QmlPreview: Drop existing CUs when replacing a file

When the client wants us to use a new version of the file we shouldn't
let the already existing compilation units get in the way.

Amends commit 6468df7657f6af4de8727363c7f7d97b680b1867

Pick-to: 6.9 6.8
Fixes: QTBUG-129329
Change-Id: Ic4b6a0194d58412e213688959251209a94ef50f3
Reviewed-by: Sami Shalayel <[email protected]>
Reviewed-by: Fabian Kosmale <[email protected]>

2 files changed, 36 insertions, 4 deletions

diff --git a/src/plugins/qmltooling/qmldbg_preview/qqmlpreviewservice.cpp b/src/plugins/qmltooling/qmldbg_preview/qqmlpreviewservice.cpp
index ea82bf0c5b..b5b5c8b5c9 100644
--- a/src/plugins/qmltooling/qmldbg_preview/qqmlpreviewservice.cpp
+++ b/src/plugins/qmltooling/qmldbg_preview/qqmlpreviewservice.cpp
@@ -46,16 +46,22 @@ void QQmlPreviewServiceImpl::messageReceived(const QByteArray &data)
         QString path;
         QByteArray contents;
         packet >> path >> contents;
+
+        const QUrl url = path.startsWith(QLatin1Char(':'))
+                ? QUrl(QLatin1String("qrc") + path)
+                : QUrl::fromLocalFile(path);
+
+        // Drop any existing compilation units for this URL from the type registry.
+        if (const auto cu = QQmlMetaType::obtainCompilationUnit(url))
+            QQmlMetaType::unregisterInternalCompositeType(cu);
+
         emit file(path, contents);
 
         // Replace the whole scene with the first file successfully loaded over the debug
         // connection. This is an OK approximation of the root component, and if the client wants
         // something specific, it will send an explicit Load anyway.
         if (m_currentUrl.isEmpty() && path.endsWith(".qml")) {
-            if (path.startsWith(':'))
-                m_currentUrl = QUrl("qrc" + path);
-            else
-                m_currentUrl = QUrl::fromLocalFile(path);
+            m_currentUrl = url;
             emit load(m_currentUrl);
         }
         break;
diff --git a/tests/auto/qml/debugger/qqmlpreview/tst_qqmlpreview.cpp b/tests/auto/qml/debugger/qqmlpreview/tst_qqmlpreview.cpp
index d1d5964b5f..594da185a1 100644
--- a/tests/auto/qml/debugger/qqmlpreview/tst_qqmlpreview.cpp
+++ b/tests/auto/qml/debugger/qqmlpreview/tst_qqmlpreview.cpp
@@ -52,6 +52,7 @@ private slots:
     void fps();
     void unhandledFiles_data();
     void unhandledFiles();
+    void updateFile();
 };
 
 tst_QQmlPreview::tst_QQmlPreview()
@@ -399,6 +400,31 @@ void tst_QQmlPreview::unhandledFiles()
     QVERIFY(!m_files.contains(file.toLocalFile()));
 }
 
+void tst_QQmlPreview::updateFile()
+{
+    const QString file("qtquick2.qml");
+    QCOMPARE(startQmlProcess(file), ConnectSuccess);
+    QVERIFY(m_client);
+    QTRY_COMPARE(m_client->state(), QQmlDebugClient::Enabled);
+    m_client->triggerLoad(testFileUrl(file));
+    QTRY_VERIFY(m_files.contains(testFile(file)));
+    verifyProcessOutputContains("ms/degrees");
+
+    QFile input(testFile(file));
+    QVERIFY(input.open(QIODevice::ReadOnly));
+    QByteArray contents = input.readAll();
+    contents.replace("ms/degrees", "foozle/barzle");
+    contents.replace("blue", "red");
+
+    serveFile(testFile(file), contents);
+    m_client->triggerLoad(testFileUrl(file));
+    verifyProcessOutputContains("foozle/barzle");
+
+    m_process->stop();
+    QTRY_COMPARE(m_client->state(), QQmlDebugClient::NotConnected);
+    QVERIFY(m_serviceErrors.isEmpty());
+}
+
 QTEST_MAIN(tst_QQmlPreview)
 
 #include "tst_qqmlpreview.moc"