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bpo-41559: Change PEP 612 implementation to pure Python (#25449)

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Ken Jin 2021-04-28 23:38:14 +08:00 • committed by GitHub
parent c1a9535989
commit 859577c249
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4 changed files with 92 additions and 71 deletions
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76
Objects/genericaliasobject.c
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@ -156,25 +156,13 @@ error:
return NULL;
}
/* 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, ...)
// isinstance(obj, TypeVar) without importing typing.py.
// Returns -1 for errors.
static int
is_typevar(PyObject *obj)
{
va_list names;
va_start(names, num);
PyTypeObject *type = Py_TYPE(obj);
int hit = 0;
for (int i = 0; i < num; ++i) {
if (!strcmp(type->tp_name, va_arg(names, const char *))) {
hit = 1;
break;
}
}
va_end(names);
if (!hit) {
if (strcmp(type->tp_name, "TypeVar") != 0) {
return 0;
}
PyObject *module = PyObject_GetAttrString((PyObject *)type, "__module__");
@ -184,24 +172,9 @@ is_typing_name(PyObject *obj, int num, ...)
int res = PyUnicode_Check(module)
&& _PyUnicode_EqualToASCIIString(module, "typing");
Py_DECREF(module);
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)
@ -236,7 +209,7 @@ 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_typevarlike(t);
int typevar = is_typevar(t);
if (typevar < 0) {
Py_DECREF(parameters);
return NULL;
@ -306,14 +279,7 @@ subs_tvars(PyObject *obj, PyObject *params, PyObject **argitems)
if (iparam >= 0) {
arg = argitems[iparam];
}
// 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);
}
Py_INCREF(arg);
PyTuple_SET_ITEM(subargs, i, arg);
}
@ -348,19 +314,11 @@ 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;
// 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);
}
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.
@ -375,7 +333,7 @@ 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_typevarlike(arg);
int typevar = is_typevar(arg);
if (typevar < 0) {
Py_DECREF(newargs);
return NULL;
@ -384,13 +342,7 @@ ga_getitem(PyObject *self, PyObject *item)
Py_ssize_t iparam = tuple_index(alias->parameters, nparams, arg);
assert(iparam >= 0);
arg = argitems[iparam];
// convert lists to tuples to help with caching in other libaries.
if (PyList_CheckExact(arg)) {
arg = PyList_AsTuple(arg);
}
else {
Py_INCREF(arg);
}
Py_INCREF(arg);
}
else {
arg = subs_tvars(arg, alias->parameters, argitems);