Improve tst_qmlcachegen::versionChecksForAheadOfTimeUnits()

Output the messages generated by the qt.qml.diskcache logging category
while loading the original unit. This might tell us why the test
occasionally fails.

Also, make sure to clean up in case of a failure so that we don't cause
further tests to fail.

Task-number: QTBUG-98404
Change-Id: I7a6da4288721164c71bbd62d1bad0909efb35fc2
Reviewed-by: Andrei Golubev <andrei.golubev@qt.io>
Reviewed-by: Fabian Kosmale <fabian.kosmale@qt.io>
(cherry picked from commit e9eb79425535740cd28c6890f40e96aed6968e5c)

1 files changed, 14 insertions, 9 deletions

diff --git a/tests/auto/qml/qmlcachegen/tst_qmlcachegen.cpp b/tests/auto/qml/qmlcachegen/tst_qmlcachegen.cpp
index 5c84c46bf8..7ffcd2411b 100644
--- a/tests/auto/qml/qmlcachegen/tst_qmlcachegen.cpp
+++ b/tests/auto/qml/qmlcachegen/tst_qmlcachegen.cpp
@@ -387,21 +387,33 @@ void tst_qmlcachegen::versionChecksForAheadOfTimeUnits()
 
     Q_ASSERT(!temporaryModifiedCachedUnit);
     QQmlMetaType::CachedUnitLookupError error = QQmlMetaType::CachedUnitLookupError::NoError;
+    QLoggingCategory::setFilterRules("qt.qml.diskcache.debug=true");
     const QQmlPrivate::CachedQmlUnit *originalUnit = QQmlMetaType::findCachedCompilationUnit(
             QUrl("qrc:/data/versionchecks.qml"), &error);
+    QLoggingCategory::setFilterRules(QString());
     QVERIFY(originalUnit);
     QV4::CompiledData::Unit *tweakedUnit = (QV4::CompiledData::Unit *)malloc(originalUnit->qmlData->unitSize);
     memcpy(reinterpret_cast<void *>(tweakedUnit),
            reinterpret_cast<const void *>(originalUnit->qmlData),
            originalUnit->qmlData->unitSize);
     tweakedUnit->version = QV4_DATA_STRUCTURE_VERSION - 1;
-    temporaryModifiedCachedUnit = new QQmlPrivate::CachedQmlUnit{tweakedUnit, nullptr, nullptr};
 
-    auto testHandler = [](const QUrl &url) -> const QQmlPrivate::CachedQmlUnit * {
+    const auto testHandler = [](const QUrl &url) -> const QQmlPrivate::CachedQmlUnit * {
         if (url == QUrl("qrc:/data/versionchecks.qml"))
             return temporaryModifiedCachedUnit;
         return nullptr;
     };
+
+    const auto dropModifiedUnit = qScopeGuard([&testHandler]() {
+        Q_ASSERT(temporaryModifiedCachedUnit);
+        free(const_cast<QV4::CompiledData::Unit *>(temporaryModifiedCachedUnit->qmlData));
+        delete temporaryModifiedCachedUnit;
+        temporaryModifiedCachedUnit = nullptr;
+
+        QQmlMetaType::removeCachedUnitLookupFunction(testHandler);
+    });
+
+    temporaryModifiedCachedUnit = new QQmlPrivate::CachedQmlUnit{tweakedUnit, nullptr, nullptr};
     QQmlMetaType::prependCachedUnitLookupFunction(testHandler);
 
     {
@@ -415,13 +427,6 @@ void tst_qmlcachegen::versionChecksForAheadOfTimeUnits()
         CleanlyLoadingComponent component(&engine, QUrl("qrc:/data/versionchecks.qml"));
         QCOMPARE(component.status(), QQmlComponent::Ready);
     }
-
-    Q_ASSERT(temporaryModifiedCachedUnit);
-    free(const_cast<QV4::CompiledData::Unit *>(temporaryModifiedCachedUnit->qmlData));
-    delete temporaryModifiedCachedUnit;
-    temporaryModifiedCachedUnit = nullptr;
-
-    QQmlMetaType::removeCachedUnitLookupFunction(testHandler);
 }
 
 void tst_qmlcachegen::retainedResources()