Issue #24695: Fix a regression in traceback.print_exception()

If exc_traceback is None we shouldn't print a traceback header
like described in the documentation.

1 files changed, 3 insertions, 1 deletions

diff --git a/Lib/traceback.py b/Lib/traceback.py
index 61c9fb57ac..02edeb6217 100644
--- a/Lib/traceback.py
+++ b/Lib/traceback.py
@@ -453,6 +453,7 @@ class TracebackException:
                 _seen=_seen)
         else:
             context = None
+        self.exc_traceback = exc_traceback
         self.__cause__ = cause
         self.__context__ = context
         self.__suppress_context__ = \
@@ -561,6 +562,7 @@ class TracebackException:
                 not self.__suppress_context__):
                 yield from self.__context__.format(chain=chain)
                 yield _context_message
-        yield 'Traceback (most recent call last):\n'
+        if self.exc_traceback is not None:
+            yield 'Traceback (most recent call last):\n'
         yield from self.stack.format()
         yield from self.format_exception_only()