fix: support PyPy 8.0.0 (3.11 and 3.12)

.github/workflows/ci.yml

@@ -48,8 +48,11 @@ jobs:
             python-version: '3.14t'
             cmake-args: -DCMAKE_CXX_STANDARD=17 -DPYBIND11_TEST_SMART_HOLDER=ON
           - runs-on: ubuntu-latest
-            python-version: 'pypy-3.11-v7.3.23'
+            python-version: 'pypy-3.11-v8.0.0'
             cmake-args: -DCMAKE_CXX_STANDARD=17
+          - runs-on: ubuntu-latest
+            python-version: 'pypy-3.12-v8.0.0'
+            cmake-args: -DCMAKE_CXX_STANDARD=20
           - runs-on: ubuntu-latest
             python-version: 'graalpy-25.0'
             cmake-args: -DCMAKE_CXX_STANDARD=20
@@ -138,7 +141,7 @@ jobs:
             python-version: '3.15'
             cmake-args: -DCMAKE_CXX_STANDARD=17
           - runs-on: macos-latest
-            python-version: 'pypy-3.11-v7.3.23'
+            python-version: 'pypy-3.12-v8.0.0'
           - runs-on: macos-latest
             python-version: 'graalpy-25.0'
           - runs-on: macos-latest
@@ -172,6 +175,9 @@ jobs:
           - runs-on: windows-latest
             python-version: 'pypy3.11'
             cmake-args: -DCMAKE_CXX_STANDARD=20
+          - runs-on: windows-latest
+            python-version: 'pypy3.12'
+            cmake-args: -DCMAKE_CXX_STANDARD=17
           # The setup-python action currently doesn't have graalpy for windows
           # See https://github.com/actions/setup-python/pull/880
 

include/pybind11/detail/class-inl.h

@@ -407,6 +407,17 @@ PYBIND11_INLINE void clear_patients(PyObject *self) {
     }
 }
 
+PYBIND11_INLINE PyObject **instance_dict_ptr(PyObject *self) {
+#if defined(PYPY_VERSION)
+    // PyPy 3.12's _PyObject_GetDictPtr() aborts if called from tp_dealloc.
+    auto offset = Py_TYPE(self)->tp_dictoffset;
+    return offset > 0 ? reinterpret_cast<PyObject **>(reinterpret_cast<char *>(self) + offset)
+                      : nullptr;
+#else
+    return _PyObject_GetDictPtr(self);
+#endif
+}
+
 PYBIND11_INLINE void clear_instance(PyObject *self) {
     auto *instance = reinterpret_cast<detail::instance *>(self);
 
@@ -436,7 +447,7 @@ PYBIND11_INLINE void clear_instance(PyObject *self) {
         PyObject_ClearWeakRefs(self);
     }
 
-    PyObject **dict_ptr = _PyObject_GetDictPtr(self);
+    PyObject **dict_ptr = instance_dict_ptr(self);
     if (dict_ptr) {
         Py_CLEAR(*dict_ptr);
     }
@@ -525,7 +536,7 @@ extern "C" PYBIND11_INLINE int pybind11_traverse(PyObject *self, visitproc visit
         return ret;
     }
 #else
-    PyObject *&dict = *_PyObject_GetDictPtr(self);
+    PyObject *&dict = *instance_dict_ptr(self);
     Py_VISIT(dict);
 #endif
     // https://docs.python.org/3/c-api/typeobj.html#c.PyTypeObject.tp_traverse
@@ -537,7 +548,7 @@ extern "C" PYBIND11_INLINE int pybind11_clear(PyObject *self) {
 #if PY_VERSION_HEX >= 0x030D0000
     PyObject_ClearManagedDict(self);
 #else
-    PyObject *&dict = *_PyObject_GetDictPtr(self);
+    PyObject *&dict = *instance_dict_ptr(self);
     Py_CLEAR(dict);
 #endif
     return 0;

include/pybind11/detail/class.h

@@ -122,6 +122,9 @@ void add_patient(PyObject *nurse, PyObject *patient);
 
 void clear_patients(PyObject *self);
 
+/// Returns the address of the instance `__dict__` slot, or nullptr if there is none.
+PyObject **instance_dict_ptr(PyObject *self);
+
 /// Clears all internal data from the instance and removes it from registered instances in
 /// preparation for deallocation.
 void clear_instance(PyObject *self);

include/pybind11/pytypes-inl.h

@@ -265,8 +265,21 @@ PYBIND11_INLINE memoryview memoryview::from_buffer(void *ptr,
     view.itemsize = itemsize;
     view.format = const_cast<char *>(format);
     view.ndim = static_cast<int>(ndim);
+#if defined(PYPY_VERSION)
+    // PyPy (at least up to 8.0.0) only copies shape and strides that point to its inline arrays.
+    if (ndim > PyBUF_MAX_NDIM) {
+        pybind11_fail("memoryview: too many dimensions");
+    }
+    for (size_t i = 0; i < ndim; ++i) {
+        view._shape[i] = (*shape)[i];
+        view._strides[i] = (*strides)[i];
+    }
+    view.shape = view._shape;
+    view.strides = view._strides;
+#else
     view.shape = shape->data();
     view.strides = strides->data();
+#endif
     view.suboffsets = nullptr;
     view.internal = nullptr;
     PyObject *obj = PyMemoryView_FromBuffer(&view);

tests/test_class.py

@@ -622,6 +622,8 @@ class PyNonFinalFinalChild(m.IsNonFinalFinal):
 def test_exception_rvalue_abort():
     with pytest.raises(RuntimeError):
         m.PyPrintDestructor().throw_something()
+    # The destructor calls Python; on PyPy, a later GC at an arbitrary point can abort
+    pytest.gc_collect()
 
 
 # https://github.com/pybind/pybind11/issues/1568

tests/test_multiple_inheritance.py

@@ -266,9 +266,13 @@ def test_mi_static_properties():
 def test_mi_dynamic_attributes():
     """Mixing bases with and without dynamic attribute support"""
 
-    for d in (m.VanillaDictMix1(), m.VanillaDictMix2()):
+    for cls in (m.VanillaDictMix1, m.VanillaDictMix2):
+        d = cls()
         d.dynamic = 1
         assert d.dynamic == 1
+        del d
+        # The dict must be cleared without crashing (PyPy 3.12)
+        pytest.gc_collect()
 
 
 def test_mi_unaligned_base():