3 files changed, 48 insertions, 1 deletions
diff --git a/sources/pyside6/libpyside/pysidesignal.cpp b/sources/pyside6/libpyside/pysidesignal.cpp
index 5df42261c..cdc3042c0 100644
--- a/sources/pyside6/libpyside/pysidesignal.cpp
+++ b/sources/pyside6/libpyside/pysidesignal.cpp
@@ -6,6 +6,7 @@
 #include "pysidesignal_p.h"
 #include "pysideutils.h"
 #include "pysidestaticstrings.h"
+#include "pysideweakref.h"
 #include "signalmanager.h"
 
 #include <shiboken.h>
@@ -342,6 +343,7 @@ static void signalInstanceFree(void *vself)
     }
     delete dataPvt;
     self->d = nullptr;
+    self->deleted = true;
     Py_TYPE(pySelf)->tp_base->tp_free(self);
 }
 
@@ -550,6 +552,13 @@ static PyObject *signalInstanceEmit(PyObject *self, PyObject *args)
 {
     PySideSignalInstance *source = reinterpret_cast<PySideSignalInstance *>(self);
 
+    // PYSIDE-2201: Check if the object has vanished meanwhile.
+    //              Tried to revive it without exception, but this gives problems.
+    if (source->deleted) {
+        PyErr_Format(PyExc_RuntimeError, "The SignalInstance object was already deleted");
+        return nullptr;
+    }
+
     Shiboken::AutoDecRef pyArgs(PyList_New(0));
     int numArgsGiven = PySequence_Fast_GET_SIZE(args);
     int numArgsInSignature = argCountInSignature(source->d->signature);
@@ -932,9 +941,16 @@ static void appendSignature(PySideSignal *self, const SignalSignature &signature
     self->data->signatures.append({signature.m_parameterTypes, signature.m_attributes});
 }
 
+static void sourceGone(void *data)
+{
+    auto *self = reinterpret_cast<PySideSignalInstance *>(data);
+    self->deleted = true;
+}
+
 static void instanceInitialize(PySideSignalInstance *self, PyObject *name, PySideSignal *signal, PyObject *source, int index)
 {
     self->d = new PySideSignalInstancePrivate;
+    self->deleted = false;
     PySideSignalInstancePrivate *selfPvt = self->d;
     selfPvt->next = nullptr;
     if (signal->data->signalName.isEmpty())
@@ -950,6 +966,10 @@ static void instanceInitialize(PySideSignalInstance *self, PyObject *name, PySid
         selfPvt->homonymousMethod = signal->homonymousMethod;
         Py_INCREF(selfPvt->homonymousMethod);
     }
+    // PYSIDE-2201: We have no reference to source. Let's take a weakref to get
+    //              notified when source gets deleted.
+    PySide::WeakRef::create(source, sourceGone, self);
+
     index++;
 
     if (index < signal->data->signatures.size()) {
@@ -1009,6 +1029,7 @@ PySideSignalInstance *newObjectFromMethod(PyObject *source, const QList<QMetaMet
             previous->d->next = item;
 
         item->d = new PySideSignalInstancePrivate;
+        item->deleted = false;
         PySideSignalInstancePrivate *selfPvt = item->d;
         selfPvt->source = source;
         Py_INCREF(selfPvt->source); // PYSIDE-79: an INCREF is missing.
diff --git a/sources/pyside6/libpyside/pysidesignal.h b/sources/pyside6/libpyside/pysidesignal.h
index c38371d81..3b82e6c58 100644
--- a/sources/pyside6/libpyside/pysidesignal.h
+++ b/sources/pyside6/libpyside/pysidesignal.h
@@ -30,6 +30,7 @@ extern "C"
     {
         PyObject_HEAD
         PySideSignalInstancePrivate *d;
+        bool deleted;
     };
 }; // extern "C"
 
diff --git a/sources/pyside6/tests/QtCore/destroysignal_test.py b/sources/pyside6/tests/QtCore/destroysignal_test.py
index 34aaded9e..f1d7cfec1 100644
--- a/sources/pyside6/tests/QtCore/destroysignal_test.py
+++ b/sources/pyside6/tests/QtCore/destroysignal_test.py
@@ -11,7 +11,7 @@ sys.path.append(os.fspath(Path(__file__).resolve().parents[1]))
 from init_paths import init_test_paths
 init_test_paths(False)
 
-from PySide6.QtCore import QTimer, QObject
+from PySide6.QtCore import QTimer, QObject, Signal
 
 
 class TestDestroySignal(unittest.TestCase):
@@ -43,6 +43,31 @@ class TestDestroySignal(unittest.TestCase):
         self.assertTrue(self._destroyed)
 
 
+class Foo(QObject):
+    s = Signal(int)
+
+    def __init__(self):
+        QObject.__init__(self)
+        sys.stderr.write(f"__init__ {id(self):x}\n")
+
+    def __del__(self):
+        sys.stderr.write(f"__del__  {id(self):x}\n")
+
+    def send(self, i):
+        self.s.emit(i)
+
+
+# PYSIDE-2201: This crashed until we introduced a weak reference.
+class TestDestroyNoConnect(unittest.TestCase):
+
+    def testSignalDestroyedMissingReference(self):
+        # This works since it has one reference more to Foo
+        Foo().send(43)
+        # This crashed because we have no reference in the signal.
+        with self.assertRaises(RuntimeError):
+            Foo().s.emit(44)
+
+
 if __name__ == '__main__':
     unittest.main()