pyqt6: FTBFS building against python 3.15

Maximiliano Curia <[email protected]> Fri, 21 Aug 2026 11:31:58 +0200

Newsgroups	gmane.linux.debian.devel.python
Message-ID	<[email protected]>

Package: src:pyqt6
Version: 6.11.0-2
User: [email protected]
Usertags: python3.15
Tags: patch

Hi!

While rebuilding the python related packages against the python version
3.15rc1 we found that pyqt6 fails to build from source[1]. This is due
to the removal of PyWeakref_GetObject which was deprecated in python
3.13. I'm attaching a patch that's almost identical to the one needed
for pyqt5.

Please consider applying this or a similar patch in your next upload.

Happy hacking,

[1]: https://debusine.debian.net/debian/r-python-python3.15/work-request/1013759/
-- 
"Can you imagine what I would do if I could do all I can?" -- Sun Tzu
Saludos /\/\ /\ >< `/

python3.15.patch (text/x-diff, 3.8 KB)

Description: Fix build against Python 3.15 by using PyWeakref_GetRef
 PyWeakref_GetObject was deprecated in Python 3.13 and removed in Python 3.15.
 Replace its usage with PyWeakref_GetRef, properly handling strong references
 and providing a compatibility fallback for older Python versions and limited API.
Author: Maximiliano Curia <[email protected]>
Forwarded: no
Last-Update: 2026-08-19

Index: pyqt6/qpy/QtCore/qpycore_pyqtslot.cpp
===================================================================
--- pyqt6.orig/qpy/QtCore/qpycore_pyqtslot.cpp
+++ pyqt6/qpy/QtCore/qpycore_pyqtslot.cpp
@@ -24,6 +24,40 @@
 #include "qpycore_pyqtslot.h"
 
 
+#if PY_VERSION_HEX < 0x030D0000
+static inline int PyWeakref_GetRef(PyObject *ref, PyObject **pobj)
+{
+    PyObject *obj;
+
+    if (ref != NULL && !PyWeakref_Check(ref))
+    {
+        *pobj = NULL;
+        PyErr_SetString(PyExc_TypeError, "expected a weakref");
+        return -1;
+    }
+
+    obj = PyWeakref_GetObject(ref);
+    if (obj == NULL)
+    {
+        *pobj = NULL;
+        return -1;
+    }
+
+    if (obj == Py_None)
+    {
+        *pobj = NULL;
+        return 0;
+    }
+
+    Py_INCREF(obj);
+    *pobj = obj;
+    return 1;
+}
+#elif defined(Py_LIMITED_API) && Py_LIMITED_API < 0x030D0000
+extern "C" PyAPI_FUNC(int) PyWeakref_GetRef(PyObject *ref, PyObject **pobj);
+#endif
+
+
 // Create the slot for a callable.
 PyQtSlot::PyQtSlot(PyObject *callable, bool callable_is_method,
         const Chimera::Signature *slot_signature)
@@ -45,6 +79,8 @@ PyQtSlot::PyQtSlot(PyObject *callable, b
 
             // Try and create a weak reference to the instance object.
             mself_wr = PyWeakref_NewRef(mself, 0);
+            if (!mself_wr)
+                PyErr_Clear();
         }
         else
         {
@@ -96,9 +132,11 @@ PyQtSlot::Result PyQtSlot::invoke(void *
     }
     else
     {
+        PyObject *self_ref = 0;
+
         // Use the value we have if one wasn't supplied.
         if (!self)
-            self = instance();
+            self = self_ref = instance();
 
         // If self is NULL then we didn't have a method in the first place.
         // Instead we had a callable that has been cleared during garbage
@@ -108,12 +146,18 @@ PyQtSlot::Result PyQtSlot::invoke(void *
 
         // See if the instance has gone (which isn't an error).
         if (self == Py_None)
+        {
+            Py_XDECREF(self_ref);
             return PyQtSlot::Ignored;
+        }
 
         // If the receiver wraps a C++ object then ignore the call if it no
         // longer exists.
         if (!no_receiver_check && PyObject_TypeCheck(self, sipSimpleWrapper_Type) && !sipGetAddress((sipSimpleWrapper *)self))
+        {
+            Py_XDECREF(self_ref);
             return PyQtSlot::Ignored;
+        }
 
         sipMethodDef callable_m;
 
@@ -121,6 +165,8 @@ PyQtSlot::Result PyQtSlot::invoke(void *
         callable_m.pm_self = self;
 
         callable = sipFromMethod(&callable_m);
+
+        Py_XDECREF(self_ref);
     }
 
     // Convert the C++ arguments to Python objects.
@@ -181,7 +227,12 @@ bool PyQtSlot::operator==(PyObject *call
         if (other)
             return false;
 
-        return (mfunc == callable_m.pm_function && instance() == callable_m.pm_self);
+        PyObject *self = instance();
+        bool match = (mfunc == callable_m.pm_function && self == callable_m.pm_self);
+
+        Py_XDECREF(self);
+
+        return match;
     }
 
     if (!other)
@@ -207,8 +258,19 @@ PyObject *PyQtSlot::instance() const
 {
     // Use the weak reference if possible.
     if (mself_wr)
-        return PyWeakref_GetObject(mself_wr);
+    {
+        PyObject *obj = 0;
+
+        if (PyWeakref_GetRef(mself_wr, &obj) < 0)
+        {
+            PyErr_Clear();
+            return 0;
+        }
+
+        return obj;
+    }
 
+    Py_XINCREF(mself);
     return mself;
 }

signature.asc (application/pgp-signature, 833 B)