Documentation/Signal slot tutorial: Recommend to use @Slot always

Task-number: PYSIDE-463
Task-number: PYSIDE-2436
Change-Id: Ida83a0b4207ab499cfaaa2090f8aabbc6246bff5
Reviewed-by: Cristian Maureira-Fredes <cristian.maureira-fredes@qt.io>
(cherry picked from commit f762506f956e06514a3188fc6dab0846c94496e6)
Reviewed-by: Qt Cherry-pick Bot <cherrypick_bot@qt-project.org>

1 files changed, 13 insertions, 0 deletions

diff --git a/sources/pyside6/doc/tutorials/basictutorial/signals_and_slots.rst b/sources/pyside6/doc/tutorials/basictutorial/signals_and_slots.rst
index d02a6d9ff..702882ffb 100644
--- a/sources/pyside6/doc/tutorials/basictutorial/signals_and_slots.rst
+++ b/sources/pyside6/doc/tutorials/basictutorial/signals_and_slots.rst
@@ -159,6 +159,19 @@ Python type. The ``name`` keyword behaves the same way as in ``Signal()``. If
 nothing is passed as name then the new slot will have the same name as the
 function that is being decorated.
 
+We recommend marking all methods used by signal connections with a
+``@QtCore.Slot()`` decorator. Not doing causes run-time overhead due to the
+method being added to the ``QMetaObject`` when creating the connection. This is
+particularly important for ``QObject`` classes registered with QML, where
+missing decorators can introduce bugs.
+
+Missing decorators can be diagnosed by setting activating warnings of the
+logging category ``qt.pyside.libpyside``; for example by setting the
+environment variable:
+
+.. code-block:: bash
+
+    export QT_LOGGING_RULES="qt.pyside.libpyside.warning=true"
 
 .. _overloading-signals-and-slots: