PEP 415: Implement suppression of __context__ display with an exception attribute

This replaces the original PEP 409 implementation. See #14133.

1 files changed, 7 insertions, 6 deletions

diff --git a/Lib/traceback.py b/Lib/traceback.py
index 35858af..eeb9e73 100644
--- a/Lib/traceback.py
+++ b/Lib/traceback.py
@@ -119,15 +119,16 @@ def _iter_chain(exc, custom_tb=None, seen=None):
         seen = set()
     seen.add(exc)
     its = []
+    context = exc.__context__
     cause = exc.__cause__
-    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:
+    if cause is not None and cause not in seen:
         its.append(_iter_chain(cause, False, seen))
         its.append([(_cause_message, None)])
+    elif (context is not None and
+          not exc.__suppress_context__ and
+          context not in seen):
+        its.append(_iter_chain(context, None, seen))
+        its.append([(_context_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: