Pyrefly giới thiệu 4 mẫu thu hẹp loại dữ liệu giúp kiểm tra kiểu trong Python trực quan hơn qua: 1. hasattr/getattr, 2. tagged unions, 3. kiểm tra độ dài tuple, 4. lưu điều kiện trong biến. Pyrefly hiện là trình kiểm tra kiểu duy nhất hỗ trợ đầy đủ các mẫu này. Tìm hiểu thêm tại trang chủ hoặc GitHub. #Python #TypeChecking #Pyrefly #LậpTrình #KiểmTraKiểu

https://www.reddit.com/r/programming/comments/1qolknv/4_pyrefly_type_narrowing_patterns_that_make/

With high-performance #Python type checkers like #Pyright, #Pyrefly, and #ty now available, what's the value proposition of #Mypy? Is it the reference implementation? Or does Mypy still have the most features? I'm not trying to knock Mypy, I'm genuinely asking because I don't know.

Let's say you want to do good type-checking for the #Python project you're working on. You pick a tool, maybe you use it as an #LSP also (so your editor can show you errors, too). As an example, I'm using #Ty at the moment. There's three places this might be installed: globally (e.g., `brew install ty`), as a dev-only dependency inside your project (e.g., `uv add --dev ty`), or -- and this one might surprise you -- it might only be used and installed by `pre-commit`, which builds a separate environment for each needed tool (which is great for instance where I use `codespell` as a `pre-commit` check, which seems to need some higher version of Python than my actual project).

Where should you install it?

If you're the only one on your team running it, globally is fine. If more than just you, then absolutely as a dev-only dependency inside your project ... and **maybe** globally as well.

The only real problem is updates. If you use a reasonable global install scheme, updates will be easy. They're less easy inside your project or in `pre-commit`. And you might care one way or the other! I **don't** want updates! I **do** want updates!

As for Python type-checking, `ty` seems good so far, but not enough experience with it yet. `basedpyright`, `pyrefly`, and `ruff` all good. These four are my favorites.

#BasedPyright #Pyrefly #Ruff #PreCommit #CodeSpell #Homebrew

Both #ty and #pyrefly reached beta recently. Pyrefly team have announced they're targeting V1 in early 2026. Given that the Pyrefly team works closely with the Django users at Instagram, I'm expecting good things from them. Early signs are good because of their experimental Django support similar to the mypy plugin.

#ty are targetting dataclass transform similar to Pyright. I doubt that'll ever be good enough.

Exciting times in Python type checking.

Well … I get symbol renaming if I use #BasedPyright as my #LSP

#Pyrefly #AdventOfCode

It seems like my #Pyrefly problem isn’t related to my #AdventOfCode project. Before pyrefly, I could rename a symbol throughout the project. With pyrefly, I can’t. More investigation needed.

Working on #AdventOfCode. My plan was to solve each day in both #Python and #RustLang. I thought I would be further by now. Yes, my Python answer to day 1 solves both parts, but I'm trying to be exemplary: good names, docstrings, comments-where-needed, tests, project structure, all the things.

For some reason, #HelixEditor keeps complaining about the #LSP (using both #Pyrefly and #Ruff, as usual). I'm concerned I haven't set things up right somehow, but I don't yet see where I've gone wrong.

Once this is working, further days will be easy. At least ... I hope!

Rustで書かれた高速Python型チェッカー「Pyrefly」の紹介
https://gihyo.jp/article/2025/12/monthly-python-2512?utm_source=feed

#gihyo #技術評論社 #gihyo_jp #Python #型チェッカー #Pyrefly #Rust

Bringing NumPy's type-completeness score to nearly 90% – Pyrefly

https://pyrefly.org/blog/numpy-type-completeness/

#HackerNews #NumPy #Pyrefly #TypeCompleteness #Python

PyreFly: Because who needs Python in Python when you can overengineer it in Rust? 🚀✨ Just pip-install this glorified type checker and bask in the glow of 166 cores and 228 GB RAM, because... why not? 🤖💻
https://pyrefly.org/?featured_on=talkpython #PyreFly #Rust #Overengineering #TypeChecker #TechInnovation #HackerNews #ngated

PyreFly: Python type checker and language server in Rust

https://pyrefly.org/?featured_on=talkpython

#HackerNews #PyreFly #Python #Rust #typechecker #language_server

I set up a language server in neovim and it didn't hurt at all. Whether it'll help remains to be seen.

vim.lsp.config('pyrefly_ls', {
  cmd = { 'pyrefly', 'lsp' },
  filetypes = { 'python' },
  root_markers = { '.git' },
})

#neovim #python #pyrefly

🎙️ Python Bytes 451: Databases are a Fad
with @mkennedy and @brianokken
https://pythonbytes.fm/episodes/show/451/databases-are-a-fad
#Python #pytest #testing #postgresql #pyrefly

I think #astral may want to consider marketing #ty a bit more.

After a bunch of my coworkers and I got back from Pycon I'm hearing WAY more from them about #pyrefly - which confuses me because while Meta has made MASSIVE contributions to FLOSS and we should all thank them for that, Astral has consistently produced outstanding #python tooling.

I know there's plenty of room in the pool and that competition is good, I'd just hate to see a great tool get overlooked because its competitor was giving away free Espresso :) :P

Introducing #Pyrefly: Meta's new #opensource #Python type checker, crafted in Rust for maximum performance!

Pyrefly is intended to replace the OCaml-based Pyre type checker previously used for Instagram’s codebase.

Find out more: https://bit.ly/4kIsRpu

#InfoQ #Meta #RustLang #TypeChecking

🐍🔧 #Rust fanboys rejoice! We've got not one, but TWO new #Python type checkers to argue about: #Pyrefly and #Ty. Because obviously what the Python ecosystem really needed was more esoteric tools nobody asked for. 😅🔍
https://blog.edward-li.com/tech/comparing-pyrefly-vs-ty/ #TypeCheckers #DeveloperCommunity #HackerNews #ngated

Pyrefly vs. Ty: Comparing Python's Two New Rust-Based Type Checkers

https://blog.edward-li.com/tech/comparing-pyrefly-vs-ty/

#HackerNews #Pyrefly #Ty #Python #Rust #TypeCheckers #Comparison

Looking for something to do at #PyConUS at 4:00 PM? Check out an open space!

West Atrium: Juggling!
Room 308: #Eurovision
Room 309: #CKAN Community
Room 309: Python, Electronics, datasheets, and component OCR
Room 315: Data engineering in Python the right way
Room 316: ORM OMG!
Room 318: Architecting in #AWS Python+#CDK. ☁️➕🐍
Room 318: Board Games!!!
Room 320: 3D and Computer Vision Meet
Room 321: Help using Python types and getting #Pyrefly type checking working in your IDE

#PyConUSOpenSpaces

🎉 Introducing *Pyrefly*, yet another shiny bauble in the endless parade of Meta's "innovations"—because clearly, #Python was desperately gasping for another type checker. 🚀 Who wouldn't want their #IDE experience mixed with a dollop of Meta's magic? 😂
https://engineering.fb.com/2025/05/15/developer-tools/introducing-pyrefly-a-new-type-checker-and-ide-experience-for-python/ #Pyrefly #Meta #Innovations #TypeChecker #HackerNews #ngated

Pyrefly: A new type checker and IDE experience for Python

https://engineering.fb.com/2025/05/15/developer-tools/introducing-pyrefly-a-new-type-checker-and-ide-experience-for-python/

#HackerNews #Pyrefly #Python #TypeChecker #IDE #Development #Tools