2021_09_08 Wagner/Thompson Check in

Type checking future

• JW – Will type annotations be infinitely reverse-compatible? Forward-compatible? Will there be a day when we start breaking things if we don’t have type annotations everywhere? Will we get in trouble in our deps don’t have it?

  • MT – The “breaking day” won’t be for a long time, like 10 years. This is because the actual PEP for typing explicitly makes it optional/cosmetic. But some libraries interpret typing at runtime (like the pydantic fire a few months ago). Also, say you’re a library developer and you make mypy run nicely. PEP 541(?) would say that you should add a special file to explicitly say that the library is annotated.

  • JW – Ok, so it sounds like we won’t forcibly break compatibility with anything by adding type annotations. So we should check on two things:

    • Ensure that this won’t cause a py3.5 interpretation error

    • Ensure that we never adopt a core functionality that REQUIRES type checking to succeed on a plugin.

• MT – With the try/except imports. How long should we provide openmm 7.5 support?

  • General – There’s no pressing need to get rid of the try/excepts.