bpo-44633: Fix parameter substitution of the union type with wrong types. (GH-27218) (GH-27224)
A TypeError is now raised instead of returning NotImplemented.
(cherry picked from commit 3ea5332a4365bdd771286b3e9692495116e9ceef)
Co-authored-by: Serhiy Storchaka <storchaka@gmail.com>
diff --git a/Lib/test/test_types.py b/Lib/test/test_types.py
index b2e1130..6ed7471 100644
--- a/Lib/test/test_types.py
+++ b/Lib/test/test_types.py
@@ -772,6 +772,12 @@ def test_union_parameter_chaining(self):
self.assertEqual((list[T] | list[S])[int, T], list[int] | list[T])
self.assertEqual((list[T] | list[S])[int, int], list[int])
+ def test_union_parameter_substitution_errors(self):
+ T = typing.TypeVar("T")
+ x = int | T
+ with self.assertRaises(TypeError):
+ x[42]
+
def test_or_type_operator_with_forward(self):
T = typing.TypeVar('T')
ForwardAfter = T | 'Forward'
diff --git a/Misc/NEWS.d/next/Core and Builtins/2021-07-17-21-04-04.bpo-44633.5-zKeI.rst b/Misc/NEWS.d/next/Core and Builtins/2021-07-17-21-04-04.bpo-44633.5-zKeI.rst
new file mode 100644
index 0000000..507a68b
--- /dev/null
+++ b/Misc/NEWS.d/next/Core and Builtins/2021-07-17-21-04-04.bpo-44633.5-zKeI.rst
@@ -0,0 +1,2 @@
+Parameter substitution of the union type with wrong types now raises
+``TypeError`` instead of returning ``NotImplemented``.
diff --git a/Objects/unionobject.c b/Objects/unionobject.c
index c744c87..c0c9a24 100644
--- a/Objects/unionobject.c
+++ b/Objects/unionobject.c
@@ -302,10 +302,22 @@ is_unionable(PyObject *obj)
PyObject *
_Py_union_type_or(PyObject* self, PyObject* other)
{
+ int r = is_unionable(self);
+ if (r > 0) {
+ r = is_unionable(other);
+ }
+ if (r < 0) {
+ return NULL;
+ }
+ if (!r) {
+ Py_RETURN_NOTIMPLEMENTED;
+ }
+
PyObject *tuple = PyTuple_Pack(2, self, other);
if (tuple == NULL) {
return NULL;
}
+
PyObject *new_union = make_union(tuple);
Py_DECREF(tuple);
return new_union;
@@ -434,6 +446,21 @@ union_getitem(PyObject *self, PyObject *item)
return NULL;
}
+ // Check arguments are unionable.
+ Py_ssize_t nargs = PyTuple_GET_SIZE(newargs);
+ for (Py_ssize_t iarg = 0; iarg < nargs; iarg++) {
+ PyObject *arg = PyTuple_GET_ITEM(newargs, iarg);
+ int is_arg_unionable = is_unionable(arg);
+ if (is_arg_unionable <= 0) {
+ Py_DECREF(newargs);
+ if (is_arg_unionable == 0) {
+ PyErr_Format(PyExc_TypeError,
+ "Each union argument must be a type, got %.100R", arg);
+ }
+ return NULL;
+ }
+ }
+
PyObject *res = make_union(newargs);
Py_DECREF(newargs);
@@ -495,21 +522,6 @@ make_union(PyObject *args)
{
assert(PyTuple_CheckExact(args));
- unionobject* result = NULL;
-
- // Check arguments are unionable.
- Py_ssize_t nargs = PyTuple_GET_SIZE(args);
- for (Py_ssize_t iarg = 0; iarg < nargs; iarg++) {
- PyObject *arg = PyTuple_GET_ITEM(args, iarg);
- int is_arg_unionable = is_unionable(arg);
- if (is_arg_unionable < 0) {
- return NULL;
- }
- if (!is_arg_unionable) {
- Py_RETURN_NOTIMPLEMENTED;
- }
- }
-
args = dedup_and_flatten_args(args);
if (args == NULL) {
return NULL;
@@ -521,7 +533,7 @@ make_union(PyObject *args)
return result1;
}
- result = PyObject_GC_New(unionobject, &_PyUnion_Type);
+ unionobject *result = PyObject_GC_New(unionobject, &_PyUnion_Type);
if (result == NULL) {
Py_DECREF(args);
return NULL;