Nick Coghlan <ncogh...@gmail.com> added the comment: The current behaviour also doesn't match the spec in PEP 3134, which states the __context__ attribute will only be set by the VM if it hasn't already been set.
This is not currently the case, as setting __context__ does not keep the VM from setting it (I also tried this setting __context__ to 1 - it was still overridden): >>> try: ... 1/0 ... finally: ... exc = RuntimeError() ... exc.__context__ = None ... raise exc ... Traceback (most recent call last): File "<stdin>", line 2, in <module> ZeroDivisionError: int division or modulo by zero During handling of the above exception, another exception occurred: Traceback (most recent call last): File "<stdin>", line 6, in <module> RuntimeError The "raise ... from ..." syntax is not the correct syntax to use however, since that relates the __cause__ atribute rather than __context__. A better approach may be to provide a "sys.clear_exc_info()" method in the sys module to allow exceptions to be raised from exception handlers without any __context__ information. A somewhat clumsy workaround that will work with current Python 3 is to defer raising the exception until after the exception handler has finished execution: >>> exc = None >>> try: ... 1/0 ... except: ... exc = RuntimeError() ... >>> if exc is not None: raise exc ... Traceback (most recent call last): File "<stdin>", line 1, in <module> RuntimeError ---------- nosy: +ncoghlan _______________________________________ Python tracker <rep...@bugs.python.org> <http://bugs.python.org/issue6210> _______________________________________ _______________________________________________ Python-bugs-list mailing list Unsubscribe: http://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
