build-std

[nikomatsakis]

Metadata
Point of contact	@davidtwco
Team(s)	cargo
Goal document	2025h1/build-std

Summary

Write an RFC for a minimum viable product (MVP) of build-std which has the potential to be
stabilised once implemented (as opposed to the currently implemented MVP which is only suitable for
experimentation and testing), and then implement it.

Tasks and status

• Discussion and moral support (cargo )
• Author RFC (@adamgemmell)
• Implementation (@adamgemmell)
• Standard reviews (cargo )

[nikomatsakis]

This issue is intended for status updates only.

For general questions or comments, please contact the owner(s) directly.

[davidtwco]

An initial update on what we've been up to and some background:

• This goal is submitted on behalf of the Rust team at Arm, but primarily worked on by @adamgemmell. Anyone interested can always contact me for updates and I'll keep this issue up-to-date.
• Our team has been trying to make progress on build-std by completing the issues in rust-lang/wg-cargo-std-aware but found this wasn't especially effective as there wasn't a clearly defined scope or desired outcome for most issues and the relevant teams were lacking in the necessary context to evaluate any proposals.
• We've since had discussions with the Cargo team and agreed to draft a document describing the use cases, motivations and prior art for build-std such that the Cargo team can feel confident in reviewing any further proposals.
  • @adamgemmell shared an initial draft of this in #t-cargo on Zulip and it is undergoing further revisions following feedback.
  • Following reaching a shared understanding of the context of the feature, @adamgemmell will then draft a complete proposal for build-std that could feasibly be stabilised. It will describe the use cases which are and are not considered in-scope for build-std, and which will feature in an initial implementation.
• @davidtwco is ensuring that whatever mechanism that is eventually proposed to enable build-std to work on stable toolchains will also be suitable for the Rust for Linux project to use when building core themselves.

[davidtwco]

A small update, @adamgemmell shared revisions to the aforementioned document, further feedback to which is being addressed.

[davidtwco]

• We've started a regular biweekly sync call with upstream stakeholders in build-std from the lang, compiler and cargo teams where we discuss aspects of our tentative design or clarify constraints.
• @adamgemmell has continued to draft our proposal for build-std, which we're discussing in our regular sync calls.
• We're hosting a session at the All Hands next week to discuss build-std.