A simple module that turns DeprecationWarning into errors when your library version or requirements change

It is notoriously difficult to keep track of deprecated function and clean dead code regularly release after release. In particular, when marking a function as deprecated, it is common to forgot mentioning the timeline of deprecation.

This forces you to actually pass a simple specification of when the deprecation should happen, and dead code be removed.

Deprecate component of your own library.

Let's say the current version of reaper have bad API, I intend to remove for 0.5, but want to keep around for the time being. I can use the following:

from reaper import deprecate

@deprecate("reaper", ">=0.5.0")
def throw_warnings(predicate, category, version, message):
    """
    This is too hard to use !
    """
    pass

This will show a DeprecationWarning to user calling the function in any version from 0.1.x to 0.4.x, and raise a DeprecationException to any user using 0.5.0-dev, or above.

• Allow to raise early on Continuous Integration system to catch using deprecated API early in development process, and still allowing you to use code locally.

• Ability to do the same base on time/date

• versions which is not a decorator/ context manager

• ability to mark version of dependency supported, and warn/raise when the minimal dependency list change:

if deprecate(`tornado`, `<=4.3.1`):
    #do stuff
else:
    # do other stuff

The first branch (or actually the predicate) should warn/raise as soon as something like tornado>=4.4 appears in requirements.txt, that some dead code has been found.