Close issue #6210: Implement PEP 409
diff --git a/Lib/traceback.py b/Lib/traceback.py
index 8d4e96e..35858af 100644
--- a/Lib/traceback.py
+++ b/Lib/traceback.py
@@ -120,14 +120,14 @@
seen.add(exc)
its = []
cause = exc.__cause__
- if cause is not None and cause not in seen:
- its.append(_iter_chain(cause, None, seen))
- its.append([(_cause_message, None)])
- else:
+ if cause is Ellipsis:
context = exc.__context__
if context is not None and context not in seen:
its.append(_iter_chain(context, None, seen))
its.append([(_context_message, None)])
+ elif cause is not None and cause not in seen:
+ its.append(_iter_chain(cause, False, seen))
+ its.append([(_cause_message, None)])
its.append([(exc, custom_tb or exc.__traceback__)])
# itertools.chain is in an extension module and may be unavailable
for it in its: