QtAsyncio: Remove application arg from loop policy

Remove the optional application argument from the constructor of
QAsyncioEventLoopPolicy, as it is unnecessary. If a QCoreApplication or
other type of qApp was created outside of QtAsyncio, it will always be
retrieved by QCoreApplication.instance(), and therefore passing it as an
argument makes little sense.

Task-number: PYSIDE-769
Change-Id: Iac7a913a1c9d6ebbb0984fe11f8b5cda955baab1
Reviewed-by: Friedemann Kleint <[email protected]>
Reviewed-by: Christian Tismer <[email protected]>

5 files changed, 12 insertions, 10 deletions

diff --git a/examples/async/eratosthenes/eratosthenes_asyncio.py b/examples/async/eratosthenes/eratosthenes_asyncio.py
index 54378daae..3f77bdbce 100644
--- a/examples/async/eratosthenes/eratosthenes_asyncio.py
+++ b/examples/async/eratosthenes/eratosthenes_asyncio.py
@@ -132,4 +132,4 @@ if __name__ == "__main__":
 
     main_window.show()
 
-    QtAsyncio.run(eratosthenes.start(), handle_sigint=True)
+    QtAsyncio.run(eratosthenes.start(), qapp=app, handle_sigint=True)
diff --git a/examples/async/minimal/minimal_asyncio.py b/examples/async/minimal/minimal_asyncio.py
index 7ffd5030f..7c4952e5c 100644
--- a/examples/async/minimal/minimal_asyncio.py
+++ b/examples/async/minimal/minimal_asyncio.py
@@ -38,4 +38,4 @@ if __name__ == "__main__":
     main_window = MainWindow()
     main_window.show()
 
-    QtAsyncio.run(handle_sigint=True)
+    QtAsyncio.run(qapp=app, handle_sigint=True)
diff --git a/sources/pyside6/PySide6/QtAsyncio/__init__.py b/sources/pyside6/PySide6/QtAsyncio/__init__.py
index 08332f621..1d5854abb 100644
--- a/sources/pyside6/PySide6/QtAsyncio/__init__.py
+++ b/sources/pyside6/PySide6/QtAsyncio/__init__.py
@@ -23,7 +23,12 @@ def run(coro: typing.Optional[typing.Coroutine] = None,
         quit_qapp: bool = True, *,
         handle_sigint: bool = False,
         debug: typing.Optional[bool] = None) -> typing.Any:
-    """Run the QtAsyncio event loop."""
+    """
+    Run the QtAsyncio event loop.
+
+    If there is no instance of a QCoreApplication, QGuiApplication or
+    QApplication yet, a new instance of QCoreApplication is created.
+    """
 
     # Event loop policies are expected to be deprecated with Python 3.13, with
     # subsequent removal in Python 3.15. At that point, part of the current
diff --git a/sources/pyside6/PySide6/QtAsyncio/events.py b/sources/pyside6/PySide6/QtAsyncio/events.py
index 1f838226d..f104f96ea 100644
--- a/sources/pyside6/PySide6/QtAsyncio/events.py
+++ b/sources/pyside6/PySide6/QtAsyncio/events.py
@@ -91,16 +91,10 @@ class QAsyncioEventLoopPolicy(asyncio.AbstractEventLoopPolicy):
     https://discuss.python.org/t/removing-the-asyncio-policy-system-asyncio-set-event-loop-policy-in-python-3-15/37553
     """
     def __init__(self,
-                 application: typing.Optional[QCoreApplication] = None,
                  quit_qapp: bool = True,
                  handle_sigint: bool = False) -> None:
         super().__init__()
-        if application is None:
-            if QCoreApplication.instance() is None:
-                application = QCoreApplication()
-            else:
-                application = QCoreApplication.instance()
-        self._application: QCoreApplication = application  # type: ignore[assignment]
+        self._application = QCoreApplication.instance() or QCoreApplication()
 
         # Configure whether the QCoreApplication at the core of QtAsyncio
         # should be shut down when asyncio finishes. A special case where one
diff --git a/sources/pyside6/doc/PySide6/QtAsyncio/index.rst b/sources/pyside6/doc/PySide6/QtAsyncio/index.rst
index 326f6efcc..0ad0f6f97 100644
--- a/sources/pyside6/doc/PySide6/QtAsyncio/index.rst
+++ b/sources/pyside6/doc/PySide6/QtAsyncio/index.rst
@@ -118,6 +118,9 @@ or
 to run the coroutine and then stop the event loop upon its completion.
 This latter case behaves identically to ``asyncio.run(my_coroutine())``.
 
+If there is no instance of a QCoreApplication, QGuiApplication or
+QApplication yet, a new instance of QCoreApplication is created.
+
 An additional optional argument ``quit_qapp`` can be passed to ``run()``
 to configure whether the QCoreApplication at the core of QtAsyncio
 should be shut down when asyncio finishes. A special case where one