Bootstrapping Starlark types

[comius]

https://docs.google.com/document/d/1Sid7EAbBd_w_T7D94Li_f_bK3zMTztFbzIMvcpzo1wY/edit?usp=sharing

[albertocavalcante]

Thanks for that!

Related Links:

• Extend Starlark syntax with type annotations #24407
• Starlark types #22935
• Optional static typing for Starlark #7468
• Support a type system starlark#106
• Add productions for type annotations. starlark#303
• https://github.com/bazelbuild/bazel/wiki/Project-Ideas#static-type-checker-for-starlark
• https://github.com/withered-magic/starpls?tab=readme-ov-file#tips-and-tricks
• https://groups.google.com/g/bazel-dev/c/u-ass4pbK7U/m/aGQF72cjCAAJ
• https://groups.google.com/g/bazel-dev/c/Pk9VrPCqby0/m/zoOL1IkxEAAJ

[brandjon]

See Starlark type system design for a bit more discussion on the current design and features we expect to support. Doesn't quite supersede the old doc, which still has a lot of good discussion and some unresolved questions.

[albertocavalcante]

@brandjon thanks for sharing this!! I've also seen the PR to https://github.com/bazelbuild/proposals/pull/413/files.

So far, it seems the focus has been on the Bazel domain for .bzl files, with Starlark-Java currently implementing this feature.

A question: I would love to see this being adopted in starlark-go, and I wonder if this opens the road to that.

I've seen the current starlark-with-types. Currently lives under a branch, as documented at https://bazel.build/rules/language#StarlarkTypes, and, per @adonovan at google/starlark-go#610 (comment), this will depend on the spec being changed first.

starlark-rust just called it out experimental and implemented it https://github.com/facebook/starlark-rust/blob/main/docs/types.md.

So my goal here would be to understand whether and when it would be possible to get a green light to start contributing type annotations to starlark-go.

Thanks!

(Maybe this conversation is more appropriate for bazelbuild/starlark#106, as this discussion is under Bazel, I don't know.)