Move non-isolated immortal objects to the right ref chain.

Author: ericsnowcurrently

Diff for: Objects/object.c

@@ -2491,6 +2491,24 @@ _Py_ResurrectReference(PyObject *op)
 
 
 #ifdef Py_TRACE_REFS
+void
+_Py_NormalizeImmortalReference(PyObject *op)
+{
+    assert(_Py_IsImmortal(op));
+    PyInterpreterState *interp = _PyInterpreterState_GET();
+    if (!_PyRefchain_IsTraced(interp, op)) {
+        return;
+    }
+    PyInterpreterState *main_interp = _PyInterpreterState_Main();
+    if (interp != main_interp
+           && interp->feature_flags & Py_RTFLAGS_USE_MAIN_OBMALLOC)
+    {
+        assert(!_PyRefchain_IsTraced(main_interp, op));
+        _PyRefchain_Remove(interp, op);
+        _PyRefchain_Trace(main_interp, op);
+    }
+}
+
 void
 _Py_ForgetReference(PyObject *op)
 {

Diff for: Objects/unicodeobject.c

@@ -15437,6 +15437,10 @@ _PyUnicode_InternStatic(PyInterpreterState *interp, PyObject **p)
     assert(*p);
 }
 
+#ifdef Py_TRACE_REFS
+extern void _Py_NormalizeImmortalReference(PyObject *);
+#endif
+
 static void
 immortalize_interned(PyObject *s)
 {
@@ -15452,6 +15456,9 @@ immortalize_interned(PyObject *s)
 #endif
     _PyUnicode_STATE(s).interned = SSTATE_INTERNED_IMMORTAL;
     _Py_SetImmortal(s);
+#ifdef Py_TRACE_REFS
+    _Py_NormalizeImmortalReference(s);
+#endif
 }
 
 static /* non-null */ PyObject*