rust-dependencies

name	rust-dependencies
description	Rust dependency management principles for this workspace. Use whenever adding, updating, removing, or reviewing dependencies in any Cargo.toml — including deciding which version to use, where to declare a dep, or auditing for duplicates.

Rules

1. Workspace-level declarations only. All dependencies must be declared in [workspace.dependencies] in the root Cargo.toml. Never add a versioned dependency directly to a crate's [dependencies].

2. Crate Cargo.toml references workspace. In each crate, reference workspace deps with:

   some-crate = { workspace = true }
   # with features:
   some-crate = { workspace = true, features = ["extra"] }
   

3. Always use the latest version. When adding a new dependency, look up and use the latest stable version on crates.io. Do not copy an old version from existing entries.

4. Check before adding. Before declaring a new dep in [workspace.dependencies], grep the root Cargo.toml to confirm it isn't already there (possibly under a different feature set).

5. No duplicate transitive deps. Avoid adding a crate that is already pulled in transitively. Run cargo tree -d to surface duplicates. Prefer cargo machete --with-metadata to detect unused deps.

Workflow

When adding a dependency:

1. Check root Cargo.toml [workspace.dependencies] — is it already declared?
2. If not, add it there with the latest version.
3. In the target crate's Cargo.toml, add { workspace = true }.
4. After changes, run make lint to catch any issues.

When removing a dependency:

1. Remove the { workspace = true } reference from the crate.
2. If no other crate uses it, remove the entry from [workspace.dependencies] too.
3. Run cargo machete --with-metadata to confirm nothing is left unused.