Add a PyType_GetName() to get type's name

Author: shihai1991

Doc/c-api/type.rst

@@ -95,6 +95,12 @@ Type Objects
    from a type's base class.  Return ``0`` on success, or return ``-1`` and sets an
    exception on error.
 
+.. c:function:: const char* PyType_GetName(PyTypeObject *type)
+
+   Return the type's name. This function can accept heap or static types.
+
+   .. versionadded:: 3.10
+
 .. c:function:: void* PyType_GetSlot(PyTypeObject *type, int slot)
 
    Return the function pointer stored in the given slot. If the

Doc/data/refcounts.dat

@@ -2309,6 +2309,9 @@ PyType_GenericNew:PyObject*:kwds:0:
 PyType_GetFlags:unsigned long:::
 PyType_GetFlags:PyTypeObject*:type:0:
 
+PyType_GetName:const char*:::
+PyType_GetName:PyTypeObject*:type:0:
+
 PyType_GetSlot:void*:::
 PyType_GetSlot:PyTypeObject*:type:0:
 PyType_GetSlot:int:slot::

Doc/whatsnew/3.10.rst

@@ -606,6 +606,9 @@ New Features
 * The :c:func:`PyType_GetSlot` function can accept static types.
   (Contributed by Hai Shi and Petr Viktorin in :issue:`41073`.)
 
+* Add a new :c:func:`PyType_GetName` function to get type's name.
+  (Contributed by Hai Shi in :issue:`42035`.)
+
 
 Porting to Python 3.10
 ----------------------

Include/object.h

@@ -232,6 +232,9 @@ PyAPI_FUNC(PyObject*) PyType_FromModuleAndSpec(PyObject *, PyType_Spec *, PyObje
 PyAPI_FUNC(PyObject *) PyType_GetModule(struct _typeobject *);
 PyAPI_FUNC(void *) PyType_GetModuleState(struct _typeobject *);
 #endif
+#if !defined(Py_LIMITED_API) || Py_LIMITED_API+0 >= 0x03100000
+PyAPI_FUNC(const char *) PyType_GetName(PyTypeObject *);
+#endif
 
 /* Generic type check */
 PyAPI_FUNC(int) PyType_IsSubtype(PyTypeObject *, PyTypeObject *);

Misc/NEWS.d/next/C API/2020-12-23-01-28-50.bpo-42035.S9eUm0.rst

@@ -0,0 +1 @@
+Add a new :c:func:`PyType_GetName` function to get type's name.

Modules/_testcapimodule.c

@@ -38,6 +38,7 @@
 #endif
 
 static struct PyModuleDef _testcapimodule;
+static PyType_Spec HeapTypeNameType_Spec;
 
 static PyObject *TestError;     /* set to exception object in init */
 
@@ -1074,6 +1075,27 @@ test_get_statictype_slots(PyObject *self, PyObject *Py_UNUSED(ignored))
 }
 
 
+static PyObject *
+test_get_type_name(PyObject *self, PyObject *Py_UNUSED(ignored))
+{
+    const char *tp_name = PyType_GetName(&PyLong_Type);
+    assert(strcmp(tp_name, "int") == 0);
+
+    tp_name = PyType_GetName(&PyModule_Type);
+    assert(strcmp(tp_name, "module") == 0);
+
+    PyObject *HeapTypeNameType = PyType_FromSpec(&HeapTypeNameType_Spec);
+    if (HeapTypeNameType == NULL) {
+        Py_RETURN_NONE;
+    }
+    tp_name = PyType_GetName((PyTypeObject *)HeapTypeNameType);
+    assert(strcmp(tp_name, "HeapTypeNameType") == 0);
+
+    Py_DECREF(HeapTypeNameType);
+    Py_RETURN_NONE;
+}
+
+
 static PyObject *
 get_args(PyObject *self, PyObject *args)
 {
@@ -5738,6 +5760,7 @@ static PyMethodDef TestMethods[] = {
     {"test_buildvalue_issue38913", test_buildvalue_issue38913,   METH_NOARGS},
     {"get_args",                get_args,                        METH_VARARGS},
     {"test_get_statictype_slots", test_get_statictype_slots,     METH_NOARGS},
+    {"test_get_type_name",        test_get_type_name,            METH_NOARGS},
     {"get_kwargs", (PyCFunction)(void(*)(void))get_kwargs,
       METH_VARARGS|METH_KEYWORDS},
     {"getargs_tuple",           getargs_tuple,                   METH_VARARGS},
@@ -6622,6 +6645,21 @@ static PyType_Spec HeapDocCType_spec = {
     HeapDocCType_slots
 };
 
+typedef struct {
+    PyObject_HEAD
+} HeapTypeNameObject;
+
+static PyType_Slot HeapTypeNameType_slots[] = {
+    {0},
+};
+
+static PyType_Spec HeapTypeNameType_Spec = {
+    .name = "_testcapi.HeapTypeNameType",
+    .basicsize = sizeof(HeapTypeNameObject),
+    .flags = Py_TPFLAGS_DEFAULT,
+    .slots = HeapTypeNameType_slots,
+};
+
 typedef struct {
     PyObject_HEAD
 } NullTpDocTypeObject;

Objects/typeobject.c

@@ -3152,6 +3152,17 @@ PyType_FromSpec(PyType_Spec *spec)
     return PyType_FromSpecWithBases(spec, NULL);
 }
 
+const char *
+PyType_GetName(PyTypeObject *type)
+{
+    assert(PyType_Check(type));
+    if (_PyType_HasFeature(type, Py_TPFLAGS_HEAPTYPE)) {
+        return PyUnicode_AsUTF8(((PyHeapTypeObject *)type)->ht_name);
+    } else {
+        return type->tp_name;
+    }
+}
+
 void *
 PyType_GetSlot(PyTypeObject *type, int slot)
 {