improve abstract property support (closes #11610)

Thanks to Darren Dale for patch.

3 files changed, 105 insertions, 3 deletions

diff --git a/Objects/descrobject.c b/Objects/descrobject.c
index 32b1593..1268df9 100644
--- a/Objects/descrobject.c
+++ b/Objects/descrobject.c
@@ -1380,6 +1380,43 @@ property_init(PyObject *self, PyObject *args, PyObject *kwds)
     return 0;
 }
 
+static PyObject *
+property_get___isabstractmethod__(propertyobject *prop, void *closure)
+{
+    int res = _PyObject_IsAbstract(prop->prop_get);
+    if (res == -1) {
+        return NULL;
+    }
+    else if (res) {
+        Py_RETURN_TRUE;
+    }
+
+    res = _PyObject_IsAbstract(prop->prop_set);
+    if (res == -1) {
+        return NULL;
+    }
+    else if (res) {
+        Py_RETURN_TRUE;
+    }
+
+    res = _PyObject_IsAbstract(prop->prop_del);
+    if (res == -1) {
+        return NULL;
+    }
+    else if (res) {
+        Py_RETURN_TRUE;
+    }
+    Py_RETURN_FALSE;
+}
+
+static PyGetSetDef property_getsetlist[] = {
+    {"__isabstractmethod__",
+     (getter)property_get___isabstractmethod__, NULL,
+     NULL,
+     NULL},
+    {NULL} /* Sentinel */
+};
+
 PyDoc_STRVAR(property_doc,
 "property(fget=None, fset=None, fdel=None, doc=None) -> property attribute\n"
 "\n"
@@ -1445,7 +1482,7 @@ PyTypeObject PyProperty_Type = {
     0,                                          /* tp_iternext */
     property_methods,                           /* tp_methods */
     property_members,                           /* tp_members */
-    0,                                          /* tp_getset */
+    property_getsetlist,                        /* tp_getset */
     0,                                          /* tp_base */
     0,                                          /* tp_dict */
     property_descr_get,                         /* tp_descr_get */
diff --git a/Objects/funcobject.c b/Objects/funcobject.c
index 2839a24..b93f340 100644
--- a/Objects/funcobject.c
+++ b/Objects/funcobject.c
@@ -814,6 +814,27 @@ static PyMemberDef cm_memberlist[] = {
     {NULL}  /* Sentinel */
 };
 
+static PyObject *
+cm_get___isabstractmethod__(classmethod *cm, void *closure)
+{
+    int res = _PyObject_IsAbstract(cm->cm_callable);
+    if (res == -1) {
+        return NULL;
+    }
+    else if (res) {
+        Py_RETURN_TRUE;
+    }
+    Py_RETURN_FALSE;
+}
+
+static PyGetSetDef cm_getsetlist[] = {
+    {"__isabstractmethod__",
+     (getter)cm_get___isabstractmethod__, NULL,
+     NULL,
+     NULL},
+    {NULL} /* Sentinel */
+};
+
 PyDoc_STRVAR(classmethod_doc,
 "classmethod(function) -> method\n\
 \n\
@@ -865,7 +886,7 @@ PyTypeObject PyClassMethod_Type = {
     0,                                          /* tp_iternext */
     0,                                          /* tp_methods */
     cm_memberlist,              /* tp_members */
-    0,                                          /* tp_getset */
+    cm_getsetlist,                              /* tp_getset */
     0,                                          /* tp_base */
     0,                                          /* tp_dict */
     cm_descr_get,                               /* tp_descr_get */
@@ -969,6 +990,27 @@ static PyMemberDef sm_memberlist[] = {
     {NULL}  /* Sentinel */
 };
 
+static PyObject *
+sm_get___isabstractmethod__(staticmethod *sm, void *closure)
+{
+    int res = _PyObject_IsAbstract(sm->sm_callable);
+    if (res == -1) {
+        return NULL;
+    }
+    else if (res) {
+        Py_RETURN_TRUE;
+    }
+    Py_RETURN_FALSE;
+}
+
+static PyGetSetDef sm_getsetlist[] = {
+    {"__isabstractmethod__",
+     (getter)sm_get___isabstractmethod__, NULL,
+     NULL,
+     NULL},
+    {NULL} /* Sentinel */
+};
+
 PyDoc_STRVAR(staticmethod_doc,
 "staticmethod(function) -> method\n\
 \n\
@@ -1017,7 +1059,7 @@ PyTypeObject PyStaticMethod_Type = {
     0,                                          /* tp_iternext */
     0,                                          /* tp_methods */
     sm_memberlist,              /* tp_members */
-    0,                                          /* tp_getset */
+    sm_getsetlist,                              /* tp_getset */
     0,                                          /* tp_base */
     0,                                          /* tp_dict */
     sm_descr_get,                               /* tp_descr_get */
diff --git a/Objects/object.c b/Objects/object.c
index ad31738..9060c82 100644
--- a/Objects/object.c
+++ b/Objects/object.c
@@ -840,6 +840,29 @@ PyObject_SetAttrString(PyObject *v, const char *name, PyObject *w)
     return res;
 }
 
+int
+_PyObject_IsAbstract(PyObject *obj)
+{
+    int res;
+    PyObject* isabstract;
+    _Py_IDENTIFIER(__isabstractmethod__);
+
+    if (obj == NULL)
+        return 0;
+
+    isabstract = _PyObject_GetAttrId(obj, &PyId___isabstractmethod__);
+    if (isabstract == NULL) {
+        if (PyErr_ExceptionMatches(PyExc_AttributeError)) {
+            PyErr_Clear();
+            return 0;
+        }
+        return -1;
+    }
+    res = PyObject_IsTrue(isabstract);
+    Py_DECREF(isabstract);
+    return res;
+}
+
 PyObject *
 _PyObject_GetAttrId(PyObject *v, _Py_Identifier *name)
 {