I noticed this when I recently added support for rust workspaces. Workspaces should support Cargo.lock.
I just put together a PR to hopefully improve Cargo.lock support for all projects. https://github.com/snapcore/snapcraft/pull/2915
Once it’s done building, it should be available to install with:
snap refresh snapcraft --channel edge/pr-2915
It would be awesome if you could give it a test run on your project!
FWIW I’m not really experienced with Rust, so if you have any thoughts on further improving the rust plugin, or this PR specifically, please let us know! 