Irit Katriel <iritkatr...@yahoo.com> added the comment:
This seems to be deliberately done here in order to prevent context cycles from forming: https://github.com/python/cpython/blob/fe6e5e7cfd68eeaa69fd1511f354a1b4d8d90990/Python/errors.c#L148 In your code you are creating a cycle where foo is the context (and cause) for bar which is the context (and cause) of the second time foo is raised. If you create a new instance of foo for the second raise then there is no cycle and you get what you expect: try: try: raise Exception('foo') except Exception as foo: print("1--", foo, foo.__context__, foo.__cause__) try: raise Exception('bar') from foo except Exception as bar: print("2--", bar, bar.__context__, bar.__context__.__context__) raise Exception('foo2') from bar except Exception as foo: wat = foo print("3--", wat, wat.__context__, wat.__context__.__context__) print("4--", wat, wat.__cause__, wat.__cause__.__context__) print("5--", wat, wat.__cause__, wat.__cause__.__cause__) Output is: 1-- foo None None 2-- bar foo None 3-- foo2 bar foo 4-- foo2 bar foo 5-- foo2 bar foo I think the bug is in your code - you can't create an exception chain that contains the same exception instance more than once. ---------- nosy: +iritkatriel _______________________________________ Python tracker <rep...@bugs.python.org> <https://bugs.python.org/issue31213> _______________________________________ _______________________________________________ Python-bugs-list mailing list Unsubscribe: https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
