New submission from Tomáš Heran <tomas.he...@oracle.com>: When embedding Python into a C/C++ based programs, one of the ways to access the formatted traceback is/was to get the type, value and tb by calling the C API PyErr_Fetch() and then call native Python traceback.format_exception() function to get a list of strings representing the tracback.
This worked fine in 2.7. Doing the same in 3.5 doesn't work because: 1. PyErr_Fetch()'s middle output argument 'value' is not an instance of Exception (or a subclass), but rather (what seems to me) a __str__ or __repr__ (i.e. the type is str) of said raised exception. An aside - this seems to be the case both in 2.7 and 3.5, but differs (in both 2.7 and 3.5, I believe) from what sys.exc_info() returns, as there the middle output 'value' is of an Exception (or a subclass) type. 2. In the overhauled traceback module in 3.x, functions like format_exception() now use an internal class TracebackException which expects the exc_value (which it gets from format_exception()'s value argument) to be an instance of Exception (or a subclass), thus feeding traceback.format_exception() whatever I got from PyErr_Fetch() ends up throwing another exception. As a temporary workaround, I can use traceback.format_tb() which luckily doesn't use the TracebackException class and works fine in 3.5. ---------- messages: 328796 nosy: tomasheran priority: normal severity: normal status: open title: format_exception() doesn't work with PyErr_Fetch versions: Python 3.5 _______________________________________ Python tracker <rep...@bugs.python.org> <https://bugs.python.org/issue35103> _______________________________________ _______________________________________________ Python-bugs-list mailing list Unsubscribe: https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
