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gh-91162: Support splitting of unpacked arbitrary-length tuple over TypeVar and TypeVarTuple parameters (alt) (GH-93412)

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For example:

  A[T, *Ts][*tuple[int, ...]] -> A[int, *tuple[int, ...]]
  A[*Ts, T][*tuple[int, ...]] -> A[*tuple[int, ...], int]
This commit is contained in:
Serhiy Storchaka
2022-06-12 16:22:01 +03:00
committed by GitHub
parent 23c9febdc6
commit 3473817106
6 changed files with 108 additions and 129 deletions
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103
Objects/genericaliasobject.c
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@@ -269,7 +269,7 @@ _Py_make_parameters(PyObject *args)
a non-empty tuple, return a new reference to obj. */
static PyObject *
subs_tvars(PyObject *obj, PyObject *params,
PyObject **argitems, Py_ssize_t nargs, Py_ssize_t varparam)
PyObject **argitems, Py_ssize_t nargs)
{
PyObject *subparams;
if (_PyObject_LookupAttr(obj, &_Py_ID(__parameters__), &subparams) < 0) {
@@ -283,28 +283,28 @@ subs_tvars(PyObject *obj, PyObject *params,
Py_DECREF(subparams);
return NULL;
}
for (Py_ssize_t i = 0, j = 0; i < nsubargs; ++i) {
Py_ssize_t j = 0;
for (Py_ssize_t i = 0; i < nsubargs; ++i) {
PyObject *arg = PyTuple_GET_ITEM(subparams, i);
Py_ssize_t iparam = tuple_index(params, nparams, arg);
if (iparam == varparam) {
j = tuple_extend(&subargs, j,
argitems + iparam, nargs - nparams + 1);
if (j < 0) {
return NULL;
}
}
else {
if (iparam >= 0) {
if (iparam > varparam) {
iparam += nargs - nparams;
if (iparam >= 0) {
PyObject *param = PyTuple_GET_ITEM(params, iparam);
arg = argitems[iparam];
if (Py_TYPE(param)->tp_iter && PyTuple_Check(arg)) { // TypeVarTuple
j = tuple_extend(&subargs, j,
&PyTuple_GET_ITEM(arg, 0),
PyTuple_GET_SIZE(arg));
if (j < 0) {
return NULL;
}
arg = argitems[iparam];
continue;
}
Py_INCREF(arg);
PyTuple_SET_ITEM(subargs, j, arg);
j++;
}
Py_INCREF(arg);
PyTuple_SET_ITEM(subargs, j, arg);
j++;
}
assert(j == PyTuple_GET_SIZE(subargs));
obj = PyObject_GetItem(obj, subargs);
@@ -409,38 +409,36 @@ _Py_subs_parameters(PyObject *self, PyObject *args, PyObject *parameters, PyObje
self);
}
item = _unpack_args(item);
for (Py_ssize_t i = 0; i < nparams; i++) {
PyObject *param = PyTuple_GET_ITEM(parameters, i);
PyObject *prepare, *tmp;
if (_PyObject_LookupAttr(param, &_Py_ID(__typing_prepare_subst__), &prepare) < 0) {
Py_DECREF(item);
return NULL;
}
if (prepare && prepare != Py_None) {
if (PyTuple_Check(item)) {
tmp = PyObject_CallFunction(prepare, "OO", self, item);
}
else {
tmp = PyObject_CallFunction(prepare, "O(O)", self, item);
}
Py_DECREF(prepare);
Py_SETREF(item, tmp);
if (item == NULL) {
return NULL;
}
}
}
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;
Py_ssize_t varparam = nparams;
for (Py_ssize_t i = 0; i < nparams; i++) {
PyObject *param = PyTuple_GET_ITEM(parameters, i);
if (Py_TYPE(param)->tp_iter) { // TypeVarTuple
if (varparam < nparams) {
Py_DECREF(item);
return PyErr_Format(PyExc_TypeError,
"More than one TypeVarTuple parameter in %S",
self);
}
varparam = i;
}
}
if (varparam < nparams) {
if (nitems < nparams - 1) {
Py_DECREF(item);
return PyErr_Format(PyExc_TypeError,
"Too few arguments for %R",
self);
}
}
else {
if (nitems != nparams) {
Py_DECREF(item);
return PyErr_Format(PyExc_TypeError,
"Too %s arguments for %R; actual %zd, expected %zd",
nitems > nparams ? "many" : "few",
self, nitems, nparams);
}
if (nitems != nparams) {
Py_DECREF(item);
return PyErr_Format(PyExc_TypeError,
"Too %s arguments for %R; actual %zd, expected %zd",
nitems > nparams ? "many" : "few",
self, nitems, nparams);
}
/* Replace all type variables (specified by parameters)
with corresponding values specified by argitems.
@@ -471,22 +469,11 @@ _Py_subs_parameters(PyObject *self, PyObject *args, PyObject *parameters, PyObje
if (subst) {
Py_ssize_t iparam = tuple_index(parameters, nparams, arg);
assert(iparam >= 0);
if (iparam == varparam) {
Py_DECREF(subst);
Py_DECREF(newargs);
Py_DECREF(item);
PyErr_SetString(PyExc_TypeError,
"Substitution of bare TypeVarTuple is not supported");
return NULL;
}
if (iparam > varparam) {
iparam += nitems - nparams;
}
arg = PyObject_CallOneArg(subst, argitems[iparam]);
Py_DECREF(subst);
}
else {
arg = subs_tvars(arg, parameters, argitems, nitems, varparam);
arg = subs_tvars(arg, parameters, argitems, nitems);
}
if (arg == NULL) {
Py_DECREF(newargs);