gh-151126: Set MemoryError on alloc failure in _PyXIData_InitWithSize

Author: KowalskiThomas

Misc/NEWS.d/next/Core_and_Builtins/2026-08-23-16-31-00.gh-issue-151126.phAWIG.rst

@@ -0,0 +1,2 @@
+Raise :exc:`MemoryError` on allocation failure in
+``_PyXIData_InitWithSize``.

Python/crossinterp.c

@@ -388,6 +388,7 @@ _PyXIData_InitWithSize(_PyXIData_t *xidata,
     _PyXIData_Init(xidata, interp, NULL, obj, new_object);
     xidata->data = PyMem_RawCalloc(1, size);
     if (xidata->data == NULL) {
+        PyErr_NoMemory();
         return -1;
     }
     xidata->free = PyMem_RawFree;