bpo-36144: Update MappingProxyType with PEP 584's operators (#18814)

We make `|=` raise TypeError, since it would be surprising if `C.__dict__ |= {'x': 0}` silently did nothing, while `C.__dict__.update({'x': 0})` is an error.

1 files changed, 25 insertions, 1 deletions

diff --git a/Objects/descrobject.c b/Objects/descrobject.c
index c96945b..4ebbb74 100644
--- a/Objects/descrobject.c
+++ b/Objects/descrobject.c
@@ -982,6 +982,30 @@ static PyMappingMethods mappingproxy_as_mapping = {
     0,                                          /* mp_ass_subscript */
 };
 
+static PyObject *
+mappingproxy_or(PyObject *left, PyObject *right)
+{
+    if (PyObject_TypeCheck(left, &PyDictProxy_Type)) {
+        left = ((mappingproxyobject*)left)->mapping;
+    }
+    if (PyObject_TypeCheck(right, &PyDictProxy_Type)) {
+        right = ((mappingproxyobject*)right)->mapping;
+    }
+    return PyNumber_Or(left, right);
+}
+
+static PyObject *
+mappingproxy_ior(PyObject *self, PyObject *Py_UNUSED(other))
+{
+    return PyErr_Format(PyExc_TypeError,
+        "'|=' is not supported by %s; use '|' instead", Py_TYPE(self)->tp_name);
+}
+
+static PyNumberMethods mappingproxy_as_number = {
+    .nb_or = mappingproxy_or,
+    .nb_inplace_or = mappingproxy_ior,
+};
+
 static int
 mappingproxy_contains(mappingproxyobject *pp, PyObject *key)
 {
@@ -1717,7 +1741,7 @@ PyTypeObject PyDictProxy_Type = {
     0,                                          /* tp_setattr */
     0,                                          /* tp_as_async */
     (reprfunc)mappingproxy_repr,                /* tp_repr */
-    0,                                          /* tp_as_number */
+    &mappingproxy_as_number,                    /* tp_as_number */
     &mappingproxy_as_sequence,                  /* tp_as_sequence */
     &mappingproxy_as_mapping,                   /* tp_as_mapping */
     0,                                          /* tp_hash */