Fix bad shutdown effect on QApplication.instance()

When

	app = QtWidgets.QApplication.instance()

is used before a QApplication has been created, the qApp code
sees no qApp instance in C++ and assumes a shutdown.

This patch keeps track of QApplication being created and
behaves correctly on that aspect.

It is still unsolved that QtCore.QObject.staticMetaObject
gets deleted on a qApp shutdown, which is too much.

I think this can be handled in another patch if at all, since
the shutdown / recreate feature is undocumented and of little use.

Change-Id: I140b6dba45f7cd337580373dbf72bc6d0a625fea
Fixes: PYSIDE-1093
Reviewed-by: Friedemann Kleint <Friedemann.Kleint@qt.io>
Reviewed-by: Cristian Maureira-Fredes <cristian.maureira-fredes@qt.io>

1 files changed, 18 insertions, 0 deletions

diff --git a/sources/pyside2/tests/pysidetest/qapp_like_a_macro_test.py b/sources/pyside2/tests/pysidetest/qapp_like_a_macro_test.py
index c58aba82e..1c0d5d55d 100644
--- a/sources/pyside2/tests/pysidetest/qapp_like_a_macro_test.py
+++ b/sources/pyside2/tests/pysidetest/qapp_like_a_macro_test.py
@@ -33,7 +33,10 @@ import PySide2
 # It also uses the qApp variable to finish the instance and start over.
 
 class qAppMacroTest(unittest.TestCase):
+    _test_1093_is_first = True
+
     def test_qApp_is_like_a_macro_and_can_restart(self):
+        self._test_1093_is_first = False
         from PySide2 import QtCore
         try:
             from PySide2 import QtGui, QtWidgets
@@ -72,5 +75,20 @@ class qAppMacroTest(unittest.TestCase):
         # and they are again all the same
         self.assertTrue(qApp is QtCore.qApp is QtGui.qApp is QtWidgets.qApp)
 
+    def test_1093(self):
+        # Test that without creating a QApplication staticMetaObject still exists.
+        # Please see https://bugreports.qt.io/browse/PYSIDE-1093 for explanation.
+        # Note: This test must run first, otherwise we would be mislead!
+        assert self._test_1093_is_first
+        from PySide2 import QtCore
+        self.assertTrue(QtCore.QObject.staticMetaObject is not None)
+        app = QtCore.QCoreApplication.instance()
+        self.assertTrue(QtCore.QObject.staticMetaObject is not None)
+        if app is None:
+            app = QtCore.QCoreApplication([])
+        self.assertTrue(QtCore.QObject.staticMetaObject is not None)
+        del __builtins__.qApp
+
+
 if __name__ == '__main__':
     unittest.main()