Curious why so many people want to implement type checkers for python? What problems are being solved that aren't covered already?
Speed.
Ty: A fast Python type checker and language server
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Re: Ty: A fast Python type checker and language server
#72:wave: Looks like you found the not-so-secret repository we're using to prepare for a broader announcement :) Please be aware this is pre-alpha software. The current version is 0.0.0a6 and the releases so far are all in service of validating our release process. We're excited to get this in people's hands, but want to set the expectation that we still have a lot of work left to do before this is production ready. Sta…
If you can say - are there any thoughts about implementing plugins / extension capabilities to keep type checking working even with libraries that aren't otherwise typecheckable? (where "not otherwise typecheckable" means types that can't be expressed with stubs - e.g., Django, dataclasses pre-PEP-681, pytest fixtures, etc.)
At least for the moment, we aren't planning on a plugin architecture. We do recognize that there are some popular libraries and code patterns that aren't easily (or at all) typeable with the current state of the typing spec. We feel it would be more useful to help drive changes to the typing spec where we can, so that other type checkers can also benefit; and/or implement workarounds for the most popular libraries directly in ty, so that a library author doesn't have to rely on their downstream consumers installing a particular set of plugins to get good type-checker results.
(It's also more difficult to support plugins effectively in a type checker like ty, than in a linter like ruff, since any non-trivial use case would likely require deep changes to how we represent types and how we implement type inference. That's not something that lends itself to a couple of simple hook extension points.)
Re: Ty: A fast Python type checker and language server
#73Earlier quoted context omitted.
Here's what I got against one of my larger open source projects: cd /tmp git clone https://github.com/simonw/sqlite-utils cd sqlite-utils uvx ty check Here's the output: https://gist.github.com/simonw/a13e1720b03e23783ae668eca7f6f... Adding "time uvx ty check" shows it took: uvx ty check 0.18s user 0.07s system 228% cpu 0.109 total
how does it compare against mypy? is it much faster?
In the same folder:
time uvx mypy .
uvx mypy . 0.46s user 0.09s system 74% cpu 0.740 total
Re: Ty: A fast Python type checker and language server
#74I gave away the “ty” project name on pypi to Astral a week or so ago. I wanted to use it for a joke a few years ago but this is a much better use for a two letter project name. They agreed to make a donation to the PSF to demonstrate their gratefulness.
I love this outcome; kudos to you and Astral both!
Re: Ty: A fast Python type checker and language server
#75Re: Ty: A fast Python type checker and language server
#76Just compared the time to check on a fairly large project: - mypy (warm cache) 18s - ty: 0.5s (and found 3500 errors) They've done it again.
Great, but how does it compare to Pyright on the utility / performance curve? Pyright is mature and already very fast. https://github.com/microsoft/pyright
Pyright is only for type-checking and it lacks many features you'd expected from a modern LSP (I forgot which). Hence, it was forked and someone created basedpyright to fix it: https://github.com/DetachHead/basedpyright
Re: Ty: A fast Python type checker and language server
#77Just compared the time to check on a fairly large project: - mypy (warm cache) 18s - ty: 0.5s (and found 3500 errors) They've done it again.
(ty developer here) This is an early preview of a pre-alpha tool, so I would expect a good chunk of those 3500 errors to be wrong at at this point :) Bug reports welcome!
Any rough estimates of how much faster you expect ty to be compared to mypy? I'd be super curious to know!
I was also one of those people who, when first trying Ruff, assumed that it didn't work the first time I ran it because of how fast it executed!
Re: Ty: A fast Python type checker and language server
#78Have these guys figured out how to make money yet?
I'm curious to see what Astral will cook up! I assume they'll probably eventually create some sort of paid devtool service.
With that being said, the worst case scenario is that they go caput, but that still leaves the python community with a set of incredible new rust-based tools. So definitely a net win for the python community either way!
Re: Ty: A fast Python type checker and language server
#79I was wondering when someone would write a type checker in Rust, seemed like an obvious thing to do given how slow mypy is.
There's Pyrefly if you wanna check it out: https://github.com/facebook/pyrefly
Re: Ty: A fast Python type checker and language server
#80Any plans to create an official ty github action? I've been loving the ruff github action.