Message8340

This works on C Python to run showing all warnings,

    $ python -W all example.py
    ...

It fails under Jython 2.7b2,

    $ jython2.7 -W all example.py
    Invalid -W option ignored: invalid action: 'all'
    ...

This is very useful for detecting things like the PendingDeprecationWarning which is silent by default.

See also issue #1906 and #1913 which touch on related issues about the command line API for the warning filters.