The astral team (behind uv and ruff) is already working on a type checker in Rust, and given the quality of their existing tools, I'm inclined to wait and see what they release. Pyrefly looks interesting, but from the repo it seems pretty early-stage and not intended for external use yet.
Also Facebook has a history of releasing the source code for something. Making a huge splash and then essentially doing nothing after 3 months (aka after someone gets their review).
They use the code internally but fail at making sure it has use externally. This is doubly the case for anything infrastructure
Buck2: Was released. Never could be built correctly without the latest nightly of Rust and even then it was fragile outside of Meta's build architecture
Sapling: Has a whole bunch of excitement and backing when it was announced. Has been essentially dead 3 mos after release.
I used to work for Meta infra. I know the MO. Have a hard time trusting.
Astral use-case is external and has a better chance of actually being supported.
We know we can't just ask for trust upfront. Instead, we want to earn it by showing up consistently and following through on our commitments. So, take us for a spin and see how we do over time. We're excited to prove ourselves!
Sorry I didn't mean it's not dead but it really hasn't got as much feature support. Things like LFS support got deproritized just because the internal team asking for it got a different feature.
Both are EXTREMELY active but only for the needs of Meta and not for the community.
Adoption outside of Meta is nearly non-existent because of this.
Look at something like Jujitsu. instead of Sapling and you can see a lot more community support, a lot more focus on features that are needed for everyone (still no LFS support, but it wasn't because Google didn't need it).
I guess I don't consider a larger number of commits as actively supporting the community. The community use is second place and the open source is just a one time boost to recruiting PR.
When I was there (which was a while ago) almost every decision was based around PSC (Performance Summary Cycle) and it's easy to justify a good rating for a large project being open sourced. Less so to make sure it's well supported for the use cases of the community.
