We talked about this briefly in the testing weekly last week and it looks pretty cool to me! As a C++ developer dabbling in Python, I've had periodic trouble dealing with dynamic typing (o_0) and the extra tests we could add against PRs seem real nice. Unfortunately mypy is apparently pretty noisy and has a number of false positives if you *don't* add the annotations, so we can't just use it for free. How do people feel about adding those annotations to our coding standards and enforcing rules on PRs about not adding warnings? Perhaps we could try it out in just the mgr, or one of the modules, if we feel like we need some experience with the tradeoffs? -Greg On Mon, Mar 4, 2019 at 1:17 AM Sebastian Wagner <swagner@xxxxxxxx> wrote: > > all, > > to find bugs in our Python code base a bit earlier, I looked into static > type checking using mypy and I'd like to share my results. > > Mypy ( http://mypy-lang.org/ ) is a static type checker for Python that > aims to combine the benefits of dynamic (or "duck") typing and static > typing. > > As of now, running mypy on our code base already reveals some genuine > bugs, especially with respect to Python 3 incompatibilities. > > Unfortunately, we will need to look into every module and message and > manually separate bugs and false-positives. > > Here are two example errors: > > > pybind/mgr/restful/decorators.py:21: error: > > Argument 1 to "split" of "bytes" has incompatible type "str"; expected "Optional[bytes]" > > > This is an issue that will be fixed by > https://github.com/ceph/ceph/pull/26712 > > > pybind/mgr/diskprediction_cloud/module.py:12: error: > > Module 'string' has no attribute 'maketrans' > > > which is already tracked as https://tracker.ceph.com/issues/38521 > > By adding additional type annotations to our Python code, we could > enhance the quality of static type checking and thus reveal additional > bugs. This is of course not mandatory! > > > Here is the PR that adds a script that calls mypy: > https://github.com/ceph/ceph/pull/26715 > > It also contains a list of messages printed by mypy.
