pyre-check VS typeshed

Internally we use Pyre for Python type checking: https://github.com/facebook/pyre-check

Before type hinting, work had intense rules and linters enforcing docstrings with types. Now, type hints and automatic pyre runs take care of all the heavy lifting.

Python now has an optional type system and if you add one of them such as mypy or pyre to your CI process and you can configure GitHub to refuse the pull request until types are added you can make it somewhat strongly typed.

If you have a preexisting codebase I believe the way you can convert it is to add the types that you know on commits and eventually you will have enough types that adding the missing ones should be easy. For the missing ones Any is a good choice.

https://pyre-check.org and https://github.com/python/mypy are popular.

So to find things in a similar space, you need to look for languages with these sorts of constraints - so things like Sorbet for Ruby or pyright/pyre and you'll see similar and new ideas

Facebook/Instagram uses Pyre which is a typechecker for Python.

I'd be curious if the pyre-check compilation is any faster for you either by removing the inlining optimization flag (the `-Oclassic` here https://github.com/facebook/pyre-check/blame/36243764ab81a82...) or whether there's a way to compile pyre-check to bytecode instead of the native compilation step (which unfortunately it looks like there's no easy way to modify pyre-check's build config to do so).

I must be doing something wrong.

[1] https://github.com/facebook/pyre-check

Some other good alternatives for type checking are Pyright (which is seen in VSCode via Microsofts PyLance plugin) and Pyre.

https://github.com/python/typeshed is Python's equivalent of DefinitelyTyped. I'm not 100% sure why it's not more of a popular thing the way DefinitelyTyped is; I think there might, to some extent, be different attitudes around the appropriateness of having third-party typings for packages, when the actual maintainer of the package isn't interested in providing first-party ones.

https://github.com/python/mypy same with typeshed https://github.com/python/typeshed

Here's the tensorflow type stubs on typeshed. https://github.com/python/typeshed/tree/main/stubs/tensorflow

Python's type hints are definitely an improvement and they're getting better all the time, but they're still frustrating to use at anything approaching the edge. I long for something as elegant and functional as TypeScript.

One hurdle I've stumbled over recently is the question "what is a type?", the answer can be surprising. Unions, for example, are types but not `Type`s. A function that takes an argument of type `Type` will not accept a Union. So if you want to write a function that effectively "casts" a parameter to a specified type, you can't. The best you can do is have an overload that accepts `Type` and does an actual cast, and then another that just turns it into `Any`. This is, in fact, how the standard library types its `cast` function [1]. The argument I've seen for the current behavior is that `Type` describes anything that can be passed to isinstance, but that's not a satisfying answer. Even then, `Union` can be passed to isinstance and still does not work with `Type`. Talk currently is to introduce a new kind of type called `TypeForm` or something to address this, which is certainly an improvement over nothing, but still feels like technical debt.

[1]: https://github.com/python/typeshed/blob/main/stdlib/typing.p...

>Ultimately if you care enough about Fody to spend over a hundred dollars worth of your time contributing to it, you probably care enough about Fody to drop them three dollars.

No, I really don't.

https://github.com/keepassxreboot/keepassxc/pull/8500 - I was randomly reading keepassxc's manpage and spotted a curious option, spent some time spelunking through the code and history to discover that it was an outdated option, sent a PR.

https://github.com/python/typeshed/pull/8617 - I converted one of the scripts I use in my DE from shell to Python, saw that VSCode has this new fancy typing support for Python, quickly found a basic bug in the type definitions for the os module, tested a fix locally, sent a PR.

https://gitlab.gnome.org/GNOME/gtk/-/issues/5250 - I found an issue with copy-paste on my phone, investigated it all the way through to the GTK stack, found the commits that introduced the issue, created a distro patch for it while discussing it with GTK upstream.

https://gitlab.alpinelinux.org/alpine/aports/-/merge_request... - I noticed that gnome-passwordsafe crashes some times, debugged it to discover that it was missing a dependency, sent a PR to the distro package to update the dependencies.

etc etc. I've made lots of fixes like these. I have no interest in paying for each and every one of them. The projects are all better off for fixes like mine and gatekeeping them on payment would've been nothing but their loss.

You have to do handling like that in other languages like TypeScript anyway.

Painpoint with type annotations:

- not being able to reuse "shapes" of data: TypedDict, NamedTuple, dataclasses.dataclass, and soon kwargs (PEP 692 [1]) all have named, typed fields now. You have to

- Since there's no generic "shape" structure that works across data types, there isn't a way to load up a JSON / YAML / TOML into a dictionary, upcast it via a `TypedGuard`, and pass it into a TypedDict / NamedTuple / Dataclass. dataclasses.asdict() or dataclasses.astuple() return naive / untyped tuples and dicts. Also the factory functions will not work with TypedDict or NamedTuple, respectively, even if you duplicate the fields by hand. See my post here: https://github.com/python/typeshed/issues/8580

- Standard library doesn't have runtime validation (e.g. pydantic / https://github.com/pydantic/pydantic).

- pytest fixtures are hard.

- Django is hard. PEP 681 may not be a saving grace either. [3]

[1] https://peps.python.org/pep-0692/

The whole Python Standard Library: https://github.com/python/typeshed/tree/master/stdlib

https://github.com/python/typeshed also provides community maintained stub packages for packages that are lacking upstream type hints

Using any linter + type checker solves many of your problems. Just annotate your types (possibly using the typing module below Python 3.10), run flake8 and mypy and you're fine. Also c.f. PEP-484 for how and why it was done like this. And use typeshed stubs for untyped libs, most major libraries have typings in there ;)

Do you mean declaration files (*.d.ts) and DefinitelyTyped? Python has equivalents of those in type stubs (*.pyi) and typeshed.