Cargo cross workspace cache

[tomassedovic]

Metadata
Point of contact	@ranger-ross
Team(s)	cargo
Goal document	2026/cargo-cross-workspace-cache

Summary

Work towards a build cache that is shared across workspaces to build times and reduce disk usage.

Tasks and status

[tomassedovic]

This issue is intended for status updates only.

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

[ranger-ross]

Update May 28, 2026

The last week for me was spent at Rust Week and the all hands.
There was a lot of good discussion about the possibilities for how the cache may work and usecases.

We are continuing the effort to stabilize the new build-dir layout in Cargo as that is a requirement for the cross workspace cache.
The stabilization PR (rust-lang/cargo#16807) has been posted and FCPed, and it is just waiting on the rust-lang/rust PR (rust-lang/rust#155439) to be merged to add support for the new layout to the compiler. I've been working through the issues and I believe we are quiet close to merging, just need to fix the remaining CI failures.