once-rust-review

name	once-rust-review
description	Project-specific PR-review rules for the tuist/once Rust workspace. Focuses on script caching, build graph work, runtime execution, `once.toml` placement, toolchain pinning, shellspec coverage, and crate structure.

Once Rust Review

This skill is intentionally narrow. Generic Rust style, formatting, naming, and most lint hygiene are already covered by rustfmt and clippy in CI, so do not flag those. Focus on the repo-specific rules below.

For each finding, cite path:line and quote the relevant snippet.

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1. Build graph work follows the RFC and keeps scripts first-class

Once starts with cacheable and remotely executable scripts plus the runtime API, and is expanding toward typed build graph capabilities. Scripts remain the migration ramp into the graph. Build graph work should follow rfcs/0001-build-graph.md, keep the agent-facing graph model typed, queryable, and structurally editable, and preserve the existing script workflow.

Flag

• Build graph CLI, rule, or query surfaces that are not tied to the RFC model, lack a clear migration path from scripts, or make scripts second-class. Severity: high.
• Docs or CLI help that position Once as Buck-compatible, Bazel-compatible, or as a drop-in replacement for Buck, Bazel, or Cargo. Severity: medium.
• Manifest parsing that accepts non-script target rules without a clear migration path and tests. Severity: high.
• Build graph changes that bypass Once's action cache, CAS, remote execution, or runtime API instead of using them as the execution substrate. Severity: medium.

Do not flag

• Script or runtime features that make individual commands cacheable, observable, or remotely executable.