gh-89188: add PyUnicode_Data and PyUnicode_GetKind

Include/cpython/unicodeobject.h

@@ -266,6 +266,12 @@ static inline void* PyUnicode_DATA(PyObject *op) {
 }
 #define PyUnicode_DATA(op) PyUnicode_DATA(_PyObject_CAST(op))
 
+/* Symbol to reexport PyUnicode_DATA without needing to read the contents
+   of the structure directly.
+*/
+PyAPI_FUNC(void *) PyUnicode_Data(PyObject *op);
+PyAPI_FUNC(int) PyUnicode_GetKind(PyObject *op);
+
 /* Return pointers to the canonical representation cast to unsigned char,
    Py_UCS2, or Py_UCS4 for direct character access.
    No checks are performed, use PyUnicode_KIND() before to ensure

Misc/NEWS.d/next/C API/2024-02-09-11-56-02.gh-issue-89188.42npsa.rst

@@ -0,0 +1 @@
+Add ``PyUnicode_Data`` and ``PyUnicode_GetKind`` as alternatives to ``PyUnicode_DATA`` and ``PyUnicode_KIND`` which don't rely on the internal structure of unicode objects.

Objects/unicodeobject.c

@@ -3863,6 +3863,22 @@ _PyUnicode_AsUTF8NoNUL(PyObject *unicode)
     return s;
 }
 
+void* PyUnicode_Data(PyObject *unicode) {
+    if (!PyUnicode_Check(unicode)) {
+        PyErr_BadArgument();
+        return NULL;
+    }
+    return PyUnicode_DATA(unicode);
+}
+
+int PyUnicode_GetKind(PyObject *unicode) {
+    if (!PyUnicode_Check(unicode)) {
+        PyErr_BadArgument();
+        return -1;
+    }
+    return PyUnicode_KIND(unicode);
+}
+
 /*
 PyUnicode_GetSize() has been deprecated since Python 3.3
 because it returned length of Py_UNICODE.