Proper clearing of WinRT factory cache

If we use winrt's factories we have to make sure to to clear the factory
cache when one of our dlls is unloaded or we will run into dangling
factory entries which might result in crashes. So we have to make sure
that winrt::clear_factory_cache is called on every dll unload.

In order not to increase compile times and dependencies too much
qfactorycacheregistration_p.h needs to be included in Qt code whenever
we use winrt's factory cache. A rule of thumb being: Include
qfactorycacheregistration_p.h whenever including winrt/base.h.

Other Qt modules which use winrt's factories need to be updated too.

Fixes: QTBUG-103611
Pick-to: 6.2 6.4
Change-Id: I7ab24e4b18bffaca653c5b7f56a66ce99212e339
Reviewed-by: Volker Hilsheimer <volker.hilsheimer@qt.io>

1 files changed, 15 insertions, 0 deletions

diff --git a/tests/auto/widgets/kernel/qapplication/tst_qapplication.cpp b/tests/auto/widgets/kernel/qapplication/tst_qapplication.cpp
index 90f365668d..6e2e6b3e49 100644
--- a/tests/auto/widgets/kernel/qapplication/tst_qapplication.cpp
+++ b/tests/auto/widgets/kernel/qapplication/tst_qapplication.cpp
@@ -128,6 +128,7 @@ private slots:
     void wheelEventPropagation();
 
     void qtbug_12673();
+    void qtbug_103611();
     void noQuitOnHide();
 
     void globalStaticObjectDestruction(); // run this last
@@ -2513,6 +2514,20 @@ void tst_QApplication::qtbug_12673()
 #endif
 }
 
+void tst_QApplication::qtbug_103611()
+{
+    {
+        int argc = 0;
+        QApplication app(argc, nullptr);
+        auto ll = QLocale().uiLanguages();
+    }
+    {
+        int argc = 0;
+        QApplication app(argc, nullptr);
+        auto ll = QLocale().uiLanguages();
+    }
+}
+
 class NoQuitOnHideWidget : public QWidget
 {
     Q_OBJECT