bpo-41559: Implement PEP 612 - Add ParamSpec and Concatenate to typing (#23702)
diff --git a/Objects/genericaliasobject.c b/Objects/genericaliasobject.c
index 756a7ce..4cc82ff 100644
--- a/Objects/genericaliasobject.c
+++ b/Objects/genericaliasobject.c
@@ -156,13 +156,24 @@ ga_repr(PyObject *self)
return NULL;
}
-// isinstance(obj, TypeVar) without importing typing.py.
-// Returns -1 for errors.
-static int
-is_typevar(PyObject *obj)
+/* Checks if a variable number of names are from typing.py.
+* If any one of the names are found, return 1, else 0.
+**/
+static inline int
+is_typing_name(PyObject *obj, int num, ...)
{
+ va_list names;
+ va_start(names, num);
+
PyTypeObject *type = Py_TYPE(obj);
- if (strcmp(type->tp_name, "TypeVar") != 0) {
+ int hit = 0;
+ for (int i = 0; i < num; ++i) {
+ if (!strcmp(type->tp_name, va_arg(names, const char *))) {
+ hit = 1;
+ break;
+ }
+ }
+ if (!hit) {
return 0;
}
PyObject *module = PyObject_GetAttrString((PyObject *)type, "__module__");
@@ -172,9 +183,25 @@ is_typevar(PyObject *obj)
int res = PyUnicode_Check(module)
&& _PyUnicode_EqualToASCIIString(module, "typing");
Py_DECREF(module);
+
+ va_end(names);
return res;
}
+// isinstance(obj, (TypeVar, ParamSpec)) without importing typing.py.
+// Returns -1 for errors.
+static inline int
+is_typevarlike(PyObject *obj)
+{
+ return is_typing_name(obj, 2, "TypeVar", "ParamSpec");
+}
+
+static inline int
+is_paramspec(PyObject *obj)
+{
+ return is_typing_name(obj, 1, "ParamSpec");
+}
+
// Index of item in self[:len], or -1 if not found (self is a tuple)
static Py_ssize_t
tuple_index(PyObject *self, Py_ssize_t len, PyObject *item)
@@ -209,7 +236,7 @@ make_parameters(PyObject *args)
Py_ssize_t iparam = 0;
for (Py_ssize_t iarg = 0; iarg < nargs; iarg++) {
PyObject *t = PyTuple_GET_ITEM(args, iarg);
- int typevar = is_typevar(t);
+ int typevar = is_typevarlike(t);
if (typevar < 0) {
Py_DECREF(parameters);
return NULL;
@@ -279,7 +306,14 @@ subs_tvars(PyObject *obj, PyObject *params, PyObject **argitems)
if (iparam >= 0) {
arg = argitems[iparam];
}
- Py_INCREF(arg);
+ // convert all the lists inside args to tuples to help
+ // with caching in other libaries
+ if (PyList_CheckExact(arg)) {
+ arg = PyList_AsTuple(arg);
+ }
+ else {
+ Py_INCREF(arg);
+ }
PyTuple_SET_ITEM(subargs, i, arg);
}
@@ -314,11 +348,19 @@ ga_getitem(PyObject *self, PyObject *item)
int is_tuple = PyTuple_Check(item);
Py_ssize_t nitems = is_tuple ? PyTuple_GET_SIZE(item) : 1;
PyObject **argitems = is_tuple ? &PyTuple_GET_ITEM(item, 0) : &item;
- if (nitems != nparams) {
- return PyErr_Format(PyExc_TypeError,
- "Too %s arguments for %R",
- nitems > nparams ? "many" : "few",
- self);
+ // A special case in PEP 612 where if X = Callable[P, int],
+ // then X[int, str] == X[[int, str]].
+ if (nparams == 1 && nitems > 1 && is_tuple &&
+ is_paramspec(PyTuple_GET_ITEM(alias->parameters, 0))) {
+ argitems = &item;
+ }
+ else {
+ if (nitems != nparams) {
+ return PyErr_Format(PyExc_TypeError,
+ "Too %s arguments for %R",
+ nitems > nparams ? "many" : "few",
+ self);
+ }
}
/* Replace all type variables (specified by alias->parameters)
with corresponding values specified by argitems.
@@ -333,7 +375,7 @@ ga_getitem(PyObject *self, PyObject *item)
}
for (Py_ssize_t iarg = 0; iarg < nargs; iarg++) {
PyObject *arg = PyTuple_GET_ITEM(alias->args, iarg);
- int typevar = is_typevar(arg);
+ int typevar = is_typevarlike(arg);
if (typevar < 0) {
Py_DECREF(newargs);
return NULL;
@@ -342,7 +384,13 @@ ga_getitem(PyObject *self, PyObject *item)
Py_ssize_t iparam = tuple_index(alias->parameters, nparams, arg);
assert(iparam >= 0);
arg = argitems[iparam];
- Py_INCREF(arg);
+ // convert lists to tuples to help with caching in other libaries.
+ if (PyList_CheckExact(arg)) {
+ arg = PyList_AsTuple(arg);
+ }
+ else {
+ Py_INCREF(arg);
+ }
}
else {
arg = subs_tvars(arg, alias->parameters, argitems);