rust-lombok-macros

# Rust Lombok Macros Treat `lombok-macros` as a procedural-macro dependency and API generator, not as a complete Rust equivalent of Java Lombok. Confirm every generated method's signature, visibility, failure behavior, and compatibility boundary before removing boilerplate. ## Scope Use this skill for: - DTOs, configuration snapshots, internal messages, test fixtures, and other data carriers where every field combination is valid; - reducing mechanical methods with `Getter`, `GetterMut`, `Setter`, `Data`, or `New`; - excluding explicitly identified sensitive fields with `CustomDebug`; - reviewing existing attributes, upgrading the crate, or migrating handwritten methods. Do not generate methods blindly for: - domain entities, value objects, or security boundaries that require validation; - methods with stable public contracts, custom errors, auditing, or side effects; - `Option` or `Result` access paths that must preserve absence or error information; - builders, default-value policies, serialization, comparisons, or hashing; version `2.0.32` does not provide these capabilities. Route dependency versions, features, and supply-chain policy to `rust-cargo-build`; general procedural-macro implementation to `rust-macros`; API and security review to `rust-code-review`; and broader test design to `rust-testing`. ## Workflow ### 1. Establish the exact baseline Inspect the project instead of assuming a version: ```bash rustc --version --verbose cargo metadata --format-version 1 cargo tree -i lombok-macros -e features ``` Check `Cargo.toml`, `Cargo.lock`, the edition, `rust-version`, and supported targets. Version `2.0.32` uses Edition 2024 and does not declare a Rust version, so compile it on the project's actual MSRV. Do not infer the selected version only from the current crates.io page or a GitHub release badge. When adding the dependency, use `cargo add lombok-macros` or an explicit reviewed version such as `cargo add lombok-macros@2.0.32`. Never copy `lombok-macros = "latest"` into `Cargo.toml`; Cargo dependencies use semantic version requirements, not a `latest` keyword. ### 2. Triage examples by crate version Do not assume that a blog post, generated answer, or older snippet matches the locked crate. In particular, `2.0.32` does not export a `Lombok` derive. Rewrite examples such as `#[derive(Lombok, Debug, Clone)]` with the smallest current derives, for example `#[derive(Getter, Setter, Debug, Clone)]`, or use `Data` only when mutable getters are also intended. Keep capability ownership explicit: - `Debug` and `Clone` are standard-library derives, not features generated by `lombok-macros`. - `CustomDebug` is the crate-provided alternative when selected fields must be skipped. - `DisplayDebug` and `DisplayDebugFormat` implement `Display` from an existing `Debug` representation; they do not make Debug output a stable presentation format. - A procedural macro removes handwritten source but still adds compile-time work and generated behavior. Do not describe it as cost-free without qualification. ### 3. Inventory the pre-generation API Record each field's existing method signature, visibility, ownership behavior, validation, side effects, errors, and callers. Replace a method only when the generated interface is equivalent or the contract change has been accepted. Select the smallest derive: | Requirement | Derive | Default risk | |---|---|---| | Read-only access | `Getter` | Default `Option` and `Result` getters unwrap and return the inner value | | Mutable borrowing | `GetterMut` | Callers can bypass field invariants | | Direct replacement | `Setter` | Setters do not validate and add write access | | All three accessor types | `Data` | The API surface is often wider than necessary | | All-field construction | `New` | The constructor is public by default; skipped fields use `Default` | | Redacted debug output | `CustomDebug` | New sensitive fields still require explicit review | | Debug reused as Display | `DisplayDebug*` | Structural output leaks easily and is not a stable user contract | ### 4. Make generated semantics explicit Write attributes against the locked version's source and documentation. For `2.0.32`: ```rust use lombok_macros::{CustomDebug, Getter, New, Setter}; #[derive(Getter, Setter, New, CustomDebug)] #[new(pub(crate))] struct WorkerConfig { #[get(pub)] #[set(pub, type(Into<String>))] name: String, #[get(pub, type(copy))] #[set(pub)] workers: usize, #[debug(skip)] #[new(skip)] token: String, } ``` - Return `&T` for expensive values unless callers require ownership. - Use `type(clone)` only when cloning is part of the API contract. - Use `type(copy)` when value semantics are required for a `Copy` field. - Do not use the `#[get(pub, clone)]` shorthand shown in part of the documentation; the `2.0.32` parser requires `type(clone)`. - Use `type(Into<T>)` or `type(AsRef<T>)` for setter conversion, then compile the exact target type. - Keep visibility minimal. Generated public methods become part of a library's semver surface. Read [Macro Reference](references/macro-reference.md) for the complete derive and attribute matrix. ### 5. Preserve Rust invariants - Keep handwritten `new` or `try_new` functions when construction validates state. - Keep named methods when mutation requires validation, auditing, or coordinated field updates; do not generate `Setter` or `GetterMut` for those fields. - For `Option` and `Result`, write explicit `as_ref`, `as_deref`, or container-returning methods. Reject default getters and `type(deref)` when they introduce panic paths. - Mark keys, tokens, passwords, and personal data with `#[debug(skip)]`, then test formatted output. Review every new field later. - Write `Display` manually for CLI, user-facing error, or protocol output. Restrict `DisplayDebug` to internal diagnostics. Read [Adoption and Review](references/adoption-and-review.md) when replacing existing methods or reviewing a pull request. ### 6. Test the expanded contract through callers Add tests that call generated methods instead of only checking that the derive compiles: ```bash cargo fmt --all --check cargo check --workspace --all-targets --all-features cargo test --workspace --all-targets --all-features cargo clippy --workspace --all-targets --all-features -- -D warnings ``` Cover method visibility, return types, setter chaining, constructor argument order, `new(skip)` defaults, Debug redaction, and the continued enforcement of handwritten invariants. Rerun these contract tests after dependency upgrades. Use `cargo expand` for manual inspection when useful, but do not make a nightly-only tool the sole quality gate. ## Completion Criteria - Confirm the dependency version, source, edition, and project MSRV with a real build. - Use the smallest derive instead of defaulting to `Data`. - Confirm every generated method's signature, visibility, ownership, and panic behavior. - Keep validation, invariants, side effects, and error semantics in explicit Rust code. - Prevent sensitive fields from reaching Debug or Display, and do not expose Debug as user output. - Pass fmt, check, test, and Clippy with tests that call the generated API. ## Resources - [Macro and Attribute Reference](references/macro-reference.md) - [Adoption, Migration, and Review Checklist](references/adoption-and-review.md) - [Execution Scenarios](examples/examples.md) - `examples/golden-lombok/`: a compilable contract example locked to `2.0.32`. ## Upstream Sources - [crates.io](https://crates.io/crates/lombok-macros): confirm the published version, checksum, license, repository, features, and dependency metadata. - [docs.rs 2.0.32](https://docs.rs/lombok-macros/2.0.32/lombok_macros/): inspect the public derive macros and version-specific rustdoc; avoid the moving `latest` URL during implementation. - [GitHub source](https://github.com/crates-dev/lombok-macros): inspect implementation history, tags, issues, and unreleased changes. Compare the matching release tag, not only the default branch. - [Rust Reference: procedural macros](https://doc.rust-lang.org/reference/procedural-macros.html) If prose, rustdoc examples, and behavior disagree, treat the source included in the selected crates.io package as authoritative for generated code, reproduce the behavior in a minimal compile test, and document the discrepancy. Never silently substitute GitHub `master` behavior for the version in `Cargo.lock`. ## Data Privacy This skill does not collect, store, or transmit user data. Dependency changes may access a registry. Confirm authorization before accessing a private registry, changing credentials, or publishing a crate.