[3.12] pythongh-124785: Revert "pythongh-116510: Fix crash due to sha…

…red immortal interned strings (pythongh-124646)" (pythongh-124807)

Revert "pythongh-116510: Fix crash due to shared immortal interned strings. (pythongh-124646)"

This reverts commit 98b2ed7.
(cherry picked from commit 7bdfabe)

Co-authored-by: T. Wouters <thomas@python.org>

Objects/unicodeobject.c

@@ -286,37 +286,13 @@ hashtable_unicode_compare(const void *key1, const void *key2)
  }
 }
 
-/* Return true if this interpreter should share the main interpreter's
- intern_dict. That's important for interpreters which load basic
- single-phase init extension modules (m_size == -1). There could be interned
- immortal strings that are shared between interpreters, due to the
- PyDict_Update(mdict, m_copy) call in import_find_extension().
-
- It's not safe to deallocate those strings until all interpreters that
- potentially use them are freed. By storing them in the main interpreter, we
- ensure they get freed after all other interpreters are freed.
-*/
-static bool
-has_shared_intern_dict(PyInterpreterState *interp)
-{
- PyInterpreterState *main_interp = _PyInterpreterState_Main();
- return interp != main_interp && interp->feature_flags & Py_RTFLAGS_USE_MAIN_OBMALLOC;
-}
-
 static int
 init_interned_dict(PyInterpreterState *interp)
 {
  assert(get_interned_dict(interp) == NULL);
- PyObject *interned;
- if (has_shared_intern_dict(interp)) {
- interned = get_interned_dict(_PyInterpreterState_Main());
- Py_INCREF(interned);
- }
- else {
- interned = PyDict_New();
- if (interned == NULL) {
- return -1;
- }
+ PyObject *interned = interned = PyDict_New();
+ if (interned == NULL) {
+ return -1;
  }
  _Py_INTERP_CACHED_OBJECT(interp, interned_strings) = interned;
  return 0;
@@ -327,10 +303,7 @@ clear_interned_dict(PyInterpreterState *interp)
 {
  PyObject *interned = get_interned_dict(interp);
  if (interned != NULL) {
- if (!has_shared_intern_dict(interp)) {
- // only clear if the dict belongs to this interpreter
- PyDict_Clear(interned);
- }
+ PyDict_Clear(interned);
  Py_DECREF(interned);
  _Py_INTERP_CACHED_OBJECT(interp, interned_strings) = NULL;
  }
@@ -15163,13 +15136,6 @@ _PyUnicode_ClearInterned(PyInterpreterState *interp)
  }
  assert(PyDict_CheckExact(interned));
 
- if (has_shared_intern_dict(interp)) {
- // the dict doesn't belong to this interpreter, skip the debug
- // checks on it and just clear the pointer to it
- clear_interned_dict(interp);
- return;
- }
-
 #ifdef INTERNED_STATS
  fprintf(stderr, "releasing %zd interned strings\n",
  PyDict_GET_SIZE(interned));
@@ -15688,10 +15654,8 @@ _PyUnicode_Fini(PyInterpreterState *interp)
 {
  struct _Py_unicode_state *state = &interp->unicode;
 
- if (!has_shared_intern_dict(interp)) {
- // _PyUnicode_ClearInterned() must be called before _PyUnicode_Fini()
- assert(get_interned_dict(interp) == NULL);
- }
+ // _PyUnicode_ClearInterned() must be called before _PyUnicode_Fini()
+ assert(get_interned_dict(interp) == NULL);
 
  _PyUnicode_FiniEncodings(&state->fs_codec);