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bpo-44796: Unify TypeVar and ParamSpec substitution (GH-31143)

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Add methods __typing_subst__() in TypeVar and ParamSpec.
Simplify code by using more object-oriented approach, especially
the C code for types.GenericAlias and the Python code for
collections.abc.Callable.
This commit is contained in:
Serhiy Storchaka
2022-03-11 10:47:26 +02:00
committed by GitHub
parent 2d5835a019
commit b6a5d8590c
6 changed files with 114 additions and 152 deletions
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46
Objects/genericaliasobject.c
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@@ -152,25 +152,6 @@ error:
return NULL;
}
// isinstance(obj, TypeVar) without importing typing.py.
// Returns -1 for errors.
static int
is_typevar(PyObject *obj)
{
PyTypeObject *type = Py_TYPE(obj);
if (strcmp(type->tp_name, "TypeVar") != 0) {
return 0;
}
PyObject *module = PyObject_GetAttrString((PyObject *)type, "__module__");
if (module == NULL) {
return -1;
}
int res = PyUnicode_Check(module)
&& _PyUnicode_EqualToASCIIString(module, "typing");
Py_DECREF(module);
return res;
}
// 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)
@@ -205,13 +186,14 @@ _Py_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);
if (typevar < 0) {
PyObject *subst;
if (_PyObject_LookupAttr(t, &_Py_ID(__typing_subst__), &subst) < 0) {
Py_DECREF(parameters);
return NULL;
}
if (typevar) {
if (subst) {
iparam += tuple_add(parameters, iparam, t);
Py_DECREF(subst);
}
else {
PyObject *subparams;
@@ -295,7 +277,7 @@ _Py_subs_parameters(PyObject *self, PyObject *args, PyObject *parameters, PyObje
Py_ssize_t nparams = PyTuple_GET_SIZE(parameters);
if (nparams == 0) {
return PyErr_Format(PyExc_TypeError,
"There are no type variables left in %R",
"%R is not a generic class",
self);
}
int is_tuple = PyTuple_Check(item);
@@ -320,23 +302,23 @@ _Py_subs_parameters(PyObject *self, PyObject *args, PyObject *parameters, PyObje
}
for (Py_ssize_t iarg = 0; iarg < nargs; iarg++) {
PyObject *arg = PyTuple_GET_ITEM(args, iarg);
int typevar = is_typevar(arg);
if (typevar < 0) {
PyObject *subst;
if (_PyObject_LookupAttr(arg, &_Py_ID(__typing_subst__), &subst) < 0) {
Py_DECREF(newargs);
return NULL;
}
if (typevar) {
if (subst) {
Py_ssize_t iparam = tuple_index(parameters, nparams, arg);
assert(iparam >= 0);
arg = argitems[iparam];
Py_INCREF(arg);
arg = PyObject_CallOneArg(subst, argitems[iparam]);
Py_DECREF(subst);
}
else {
arg = subs_tvars(arg, parameters, argitems);
if (arg == NULL) {
Py_DECREF(newargs);
return NULL;
}
}
if (arg == NULL) {
Py_DECREF(newargs);
return NULL;
}
PyTuple_SET_ITEM(newargs, iarg, arg);
}