On 12/03/19 23:34, Gregory Farnum wrote: > 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? I like the idea and I think we should at the same time remove the python2 support, and start using python3.6 type annotations. This allows to avoid to write type annotations inside code comments. > -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. > -- Ricardo Dias Senior Software Engineer - Storage Team SUSE Linux GmbH, GF: Felix Imendörffer, Jane Smithard, Graham Norton, HRB 21284 (AG Nürnberg)
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