bpo-43901: Lazy-create an empty annotations dict in all unannotated user classes and modules (#25623)
Change class and module objects to lazy-create empty annotations dicts on demand. The annotations dicts are stored in the object's `__dict__` for backwards compatibility.
diff --git a/Objects/moduleobject.c b/Objects/moduleobject.c
index a6eb85b..cdb365d 100644
--- a/Objects/moduleobject.c
+++ b/Objects/moduleobject.c
@@ -12,6 +12,9 @@ static Py_ssize_t max_module_number;
_Py_IDENTIFIER(__doc__);
_Py_IDENTIFIER(__name__);
_Py_IDENTIFIER(__spec__);
+_Py_IDENTIFIER(__dict__);
+_Py_IDENTIFIER(__dir__);
+_Py_IDENTIFIER(__annotations__);
static PyMemberDef module_members[] = {
{"__dict__", T_OBJECT, offsetof(PyModuleObject, md_dict), READONLY},
@@ -807,8 +810,6 @@ module_clear(PyModuleObject *m)
static PyObject *
module_dir(PyObject *self, PyObject *args)
{
- _Py_IDENTIFIER(__dict__);
- _Py_IDENTIFIER(__dir__);
PyObject *result = NULL;
PyObject *dict = _PyObject_GetAttrId(self, &PyId___dict__);
@@ -841,6 +842,71 @@ static PyMethodDef module_methods[] = {
{0}
};
+static PyObject *
+module_get_annotations(PyModuleObject *m, void *Py_UNUSED(ignored))
+{
+ PyObject *dict = _PyObject_GetAttrId((PyObject *)m, &PyId___dict__);
+
+ if ((dict == NULL) || !PyDict_Check(dict)) {
+ PyErr_Format(PyExc_TypeError, "<module>.__dict__ is not a dictionary");
+ return NULL;
+ }
+
+ PyObject *annotations;
+ /* there's no _PyDict_GetItemId without WithError, so let's LBYL. */
+ if (_PyDict_ContainsId(dict, &PyId___annotations__)) {
+ annotations = _PyDict_GetItemIdWithError(dict, &PyId___annotations__);
+ /*
+ ** _PyDict_GetItemIdWithError could still fail,
+ ** for instance with a well-timed Ctrl-C or a MemoryError.
+ ** so let's be totally safe.
+ */
+ if (annotations) {
+ Py_INCREF(annotations);
+ }
+ } else {
+ annotations = PyDict_New();
+ if (annotations) {
+ int result = _PyDict_SetItemId(dict, &PyId___annotations__, annotations);
+ if (result) {
+ Py_CLEAR(annotations);
+ }
+ }
+ }
+ Py_DECREF(dict);
+ return annotations;
+}
+
+static int
+module_set_annotations(PyModuleObject *m, PyObject *value, void *Py_UNUSED(ignored))
+{
+ PyObject *dict = _PyObject_GetAttrId((PyObject *)m, &PyId___dict__);
+
+ if ((dict == NULL) || !PyDict_Check(dict)) {
+ PyErr_Format(PyExc_TypeError, "<module>.__dict__ is not a dictionary");
+ return -1;
+ }
+
+ if (value != NULL) {
+ /* set */
+ return _PyDict_SetItemId(dict, &PyId___annotations__, value);
+ }
+
+ /* delete */
+ if (!_PyDict_ContainsId(dict, &PyId___annotations__)) {
+ PyErr_Format(PyExc_AttributeError, "__annotations__");
+ return -1;
+ }
+
+ return _PyDict_DelItemId(dict, &PyId___annotations__);
+}
+
+
+static PyGetSetDef module_getsets[] = {
+ {"__annotations__", (getter)module_get_annotations, (setter)module_set_annotations},
+ {NULL}
+};
+
PyTypeObject PyModule_Type = {
PyVarObject_HEAD_INIT(&PyType_Type, 0)
"module", /* tp_name */
@@ -872,7 +938,7 @@ PyTypeObject PyModule_Type = {
0, /* tp_iternext */
module_methods, /* tp_methods */
module_members, /* tp_members */
- 0, /* tp_getset */
+ module_getsets, /* tp_getset */
0, /* tp_base */
0, /* tp_dict */
0, /* tp_descr_get */