Unlink the structseq type from the global list of
objects before initializing it. It might be linked
already if there was a Py_Initialize/Py_Finalize
cycle earlier; not unlinking it would break the global
list.
diff --git a/Objects/structseq.c b/Objects/structseq.c
index e1e7cfa..e074810 100644
--- a/Objects/structseq.c
+++ b/Objects/structseq.c
@@ -349,6 +349,14 @@
PyMemberDef* members;
int n_members, n_unnamed_members, i, k;
+#ifdef Py_TRACE_REFS
+ /* if the type object was chained, unchain it first
+ before overwriting its storage */
+ if (type->_ob_next) {
+ _Py_ForgetReference((PyObject*)type);
+ }
+#endif
+
n_unnamed_members = 0;
for (i = 0; desc->fields[i].name != NULL; ++i)
if (desc->fields[i].name == PyStructSequence_UnnamedField)