gh-112026: Restore removed _PyDict_GetItemStringWithError() (#112119)

Restore the removed _PyDict_GetItemStringWithError() function. It is
used by numpy.

Author: vstinner

Include/cpython/dictobject.h

@@ -34,7 +34,7 @@ typedef struct {
 
 PyAPI_FUNC(PyObject *) _PyDict_GetItem_KnownHash(PyObject *mp, PyObject *key,
                                                  Py_hash_t hash);
-
+PyAPI_FUNC(PyObject *) _PyDict_GetItemStringWithError(PyObject *, const char *);
 PyAPI_FUNC(PyObject *) PyDict_SetDefault(
     PyObject *mp, PyObject *key, PyObject *defaultobj);
 

Misc/NEWS.d/next/C API/2023-11-15-17-10-09.gh-issue-112026.ts9yyn.rst

@@ -0,0 +1,2 @@
+Restore the removed ``_PyDict_GetItemStringWithError()`` function. It is
+used by numpy. Patch by Victor Stinner.

Objects/dictobject.c

@@ -1842,6 +1842,20 @@ _PyDict_GetItemIdWithError(PyObject *dp, _Py_Identifier *key)
     return _PyDict_GetItem_KnownHash(dp, kv, hash);  // borrowed reference
 }
 
+PyObject *
+_PyDict_GetItemStringWithError(PyObject *v, const char *key)
+{
+    PyObject *kv, *rv;
+    kv = PyUnicode_FromString(key);
+    if (kv == NULL) {
+        return NULL;
+    }
+    rv = PyDict_GetItemWithError(v, kv);
+    Py_DECREF(kv);
+    return rv;
+}
+
+
 /* Fast version of global value lookup (LOAD_GLOBAL).
  * Lookup in globals, then builtins.
  *