# Rust workspaces

Cargo discovery, shared versions, dependency requirement edits, and private release behavior for Rust packages.

Source: https://semifold.noctisynth.org/docs/workspace/rust/
Language: en



The built-in Rust adapter reads and edits `Cargo.toml` for both a single Cargo package and a Cargo workspace. Cargo remains responsible for builds and dependency resolution; Semifold connects the discovered facts to repository-wide versioning and publishing.

## Package discovery [#package-discovery]

When the project-root `Cargo.toml` contains `[workspace]`, Semifold expands `workspace.members` globs and inspects member manifests. A root manifest that also contains `[package]` contributes the root package. Without a workspace, the root `Cargo.toml` is read as one package.

The Cargo package name is its manifest name. It may seed a `PackageId` during initialization, but the ID in existing configuration is the stable identity used by changesets and graph edges.

Cargo `publish = false` makes a crate unavailable for registry publishing by default. Optional package configuration `publish` can override the effective eligibility used by Semifold. `publish = true` does not remove the Cargo field, so the default `cargo publish` command may still reject it. A private crate continues to participate in version calculation, shared-version groups, file edits, and dependency ordering.

## Dependency inspection [#dependency-inspection]

The adapter reads:

* `[dependencies]`;
* `[dev-dependencies]`;
* `[build-dependencies]`;
* `[workspace.dependencies]` in the root manifest.

A dependency alias is resolved through its `package` field. When a member uses `workspace = true`, Semifold understands and updates the requirement in shared `[workspace.dependencies]` instead of inserting a duplicate version in the member manifest.

Every internal dependency participates in ordering. Currently, only runtime dependencies from `[dependencies]` receive constraint-aware automatic propagation: when a dependency's new version no longer satisfies the existing Cargo requirement, the dependent receives a `patch` release. Development and build dependencies affect order only.

## Version edits [#version-edits]

A normal package receives its target version in `package.version`. Rust manifests use format-preserving TOML edits, so an unrelated layout is not reordered for one version field.

When an internal runtime requirement needs an update, Semifold handles normal, aliased, and workspace-inherited declarations together. It only considers rewriting a requirement when the dependency's target version changes, avoiding needless normalization of a valid broad range.

## Shared workspace versions [#shared-workspace-versions]

Members may use:

```toml
[package]
version.workspace = true

[workspace.package]
version = "1.4.0"
```

Packages backed by the same `[workspace.package].version` form one version group. When any member changes:

* every member enters the release plan;
* the highest requested changeset bump applies to the group;
* every member receives the same target version;
* the root `Cargo.toml` shared version is edited once;
* a private member can advance the shared version and bring public members into the release.

All members must have exactly the same `channel` and pending `channel-bump`. A mismatch fails planning rather than choosing whichever package is visited first.

## Publishing [#publishing]

The Rust adapter only provides manifest facts and candidate edits. Registry pre-checks, pre-publish commands, and publish commands come from `[resolver.rust]` and run through the shared publisher in dependency order.

A private crate skips registry preflight and publish commands. It does not create a GitHub Release by default, but `github-release = true` can explicitly enable a Release and assets. This policy is independent of Cargo's `publish = false`.

## Common problems [#common-problems]

* A workspace member glob omits a package: fix `workspace.members` instead of inventing the package only in Semifold configuration.
* `version.workspace = true` has no valid `[workspace.package].version`: provide the shared source.
* Two crates have the same package name: remove the Cargo-level ambiguity; changing only `PackageId` cannot make manifest dependency matching unique.
* A Rust change must republish a Node.js or Python binding: add a cross-ecosystem `depends-on` to the binding package.