PyPy has recently released a reverse debugger for Python: https://mail.python.org/pipermail/pypy-dev/2016-September/014661.html
Armin Rigo wrote: [quote] It is my pleasure to announce the first beta release of RevDB: a "reverse debugger" for Python. A reverse debugger is a debugger where you can go forward and backward in time. RevDB is designed to track down the annoying, hard-to- reproduce bug in your Python program. -- Steven git gets easier once you get the basic idea that branches are homeomorphic endofunctors mapping submanifolds of a Hilbert space. -- https://mail.python.org/mailman/listinfo/python-list