gh-92216: improve performance of `hasattr` for type objects (GH-99979)
diff --git a/Include/internal/pycore_typeobject.h b/Include/internal/pycore_typeobject.h
index c207ce6..4d70574 100644
--- a/Include/internal/pycore_typeobject.h
+++ b/Include/internal/pycore_typeobject.h
@@ -74,6 +74,10 @@ extern static_builtin_state * _PyStaticType_GetState(PyTypeObject *);
extern void _PyStaticType_ClearWeakRefs(PyTypeObject *type);
extern void _PyStaticType_Dealloc(PyTypeObject *type);
+PyObject *
+_Py_type_getattro_impl(PyTypeObject *type, PyObject *name, int *suppress_missing_attribute);
+PyObject *
+_Py_type_getattro(PyTypeObject *type, PyObject *name);
PyObject *_Py_slot_tp_getattro(PyObject *self, PyObject *name);
PyObject *_Py_slot_tp_getattr_hook(PyObject *self, PyObject *name);
diff --git a/Misc/NEWS.d/next/Core and Builtins/2022-12-04-00-38-33.gh-issue-92216.CJXuWB.rst b/Misc/NEWS.d/next/Core and Builtins/2022-12-04-00-38-33.gh-issue-92216.CJXuWB.rst
new file mode 100644
index 0000000..f7ef52d
--- /dev/null
+++ b/Misc/NEWS.d/next/Core and Builtins/2022-12-04-00-38-33.gh-issue-92216.CJXuWB.rst
@@ -0,0 +1 @@
+Improve the performance of :func:`hasattr` for type objects with a missing attribute.
diff --git a/Objects/object.c b/Objects/object.c
index 028b0ed..fae508c 100644
--- a/Objects/object.c
+++ b/Objects/object.c
@@ -939,7 +939,15 @@ _PyObject_LookupAttr(PyObject *v, PyObject *name, PyObject **result)
}
return 0;
}
- if (tp->tp_getattro != NULL) {
+ if (tp->tp_getattro == (getattrofunc)_Py_type_getattro) {
+ int supress_missing_attribute_exception = 0;
+ *result = _Py_type_getattro_impl((PyTypeObject*)v, name, &supress_missing_attribute_exception);
+ if (supress_missing_attribute_exception) {
+ // return 0 without having to clear the exception
+ return 0;
+ }
+ }
+ else if (tp->tp_getattro != NULL) {
*result = (*tp->tp_getattro)(v, name);
}
else if (tp->tp_getattr != NULL) {
diff --git a/Objects/typeobject.c b/Objects/typeobject.c
index a96f993..16b1a30 100644
--- a/Objects/typeobject.c
+++ b/Objects/typeobject.c
@@ -4219,9 +4219,19 @@ _PyType_LookupId(PyTypeObject *type, _Py_Identifier *name)
}
/* This is similar to PyObject_GenericGetAttr(),
- but uses _PyType_Lookup() instead of just looking in type->tp_dict. */
-static PyObject *
-type_getattro(PyTypeObject *type, PyObject *name)
+ but uses _PyType_Lookup() instead of just looking in type->tp_dict.
+
+ The argument suppress_missing_attribute is used to provide a
+ fast path for hasattr. The possible values are:
+
+ * NULL: do not suppress the exception
+ * Non-zero pointer: suppress the PyExc_AttributeError and
+ set *suppress_missing_attribute to 1 to signal we are returning NULL while
+ having suppressed the exception (other exceptions are not suppressed)
+
+ */
+PyObject *
+_Py_type_getattro_impl(PyTypeObject *type, PyObject *name, int * suppress_missing_attribute)
{
PyTypeObject *metatype = Py_TYPE(type);
PyObject *meta_attribute, *attribute;
@@ -4301,12 +4311,25 @@ type_getattro(PyTypeObject *type, PyObject *name)
}
/* Give up */
- PyErr_Format(PyExc_AttributeError,
- "type object '%.50s' has no attribute '%U'",
- type->tp_name, name);
+ if (suppress_missing_attribute == NULL) {
+ PyErr_Format(PyExc_AttributeError,
+ "type object '%.50s' has no attribute '%U'",
+ type->tp_name, name);
+ } else {
+ // signal the caller we have not set an PyExc_AttributeError and gave up
+ *suppress_missing_attribute = 1;
+ }
return NULL;
}
+/* This is similar to PyObject_GenericGetAttr(),
+ but uses _PyType_Lookup() instead of just looking in type->tp_dict. */
+PyObject *
+_Py_type_getattro(PyTypeObject *type, PyObject *name)
+{
+ return _Py_type_getattro_impl(type, name, NULL);
+}
+
static int
type_setattro(PyTypeObject *type, PyObject *name, PyObject *value)
{
@@ -4798,7 +4821,7 @@ PyTypeObject PyType_Type = {
0, /* tp_hash */
(ternaryfunc)type_call, /* tp_call */
0, /* tp_str */
- (getattrofunc)type_getattro, /* tp_getattro */
+ (getattrofunc)_Py_type_getattro, /* tp_getattro */
(setattrofunc)type_setattro, /* tp_setattro */
0, /* tp_as_buffer */
Py_TPFLAGS_DEFAULT | Py_TPFLAGS_HAVE_GC |
