1 files changed, 8 insertions, 0 deletions
diff --git a/Modules/_testmultiphase.c b/Modules/_testmultiphase.c
index 5776df7..c6dfc2f 100644
--- a/Modules/_testmultiphase.c
+++ b/Modules/_testmultiphase.c
@@ -624,6 +624,14 @@ bad_traverse(PyObject *self, visitproc visit, void *arg) {
     testmultiphase_state *m_state;
 
     m_state = PyModule_GetState(self);
+
+    /* The following assertion mimics any traversal function that doesn't correctly handle
+     * the case during module creation where the module state hasn't been created yet.
+     *
+     * The check that it is used to test only runs in debug mode, so it is OK that the
+     * assert() will get compiled out in fully optimised release builds.
+     */
+    assert(m_state != NULL);
     Py_VISIT(m_state->integer);
     return 0;
 }