If an error is encountered while formatting the message in a logging call, for
example ``logging.warning("oh no!: %s: %s", "first")`` (a second argument is
missing), pytest now propagates the error, likely causing the test to fail.

Previously, such a mistake would cause an error to be printed to stderr, which
is not displayed by default for passing tests. This change makes the mistake
visible during testing.

You may supress this behavior temporarily or permanently by setting
``logging.raiseExceptions = False``.