tzlint-performance - SKILL.md Agent Skill

name: tzlint-performance description: Hot-path performance rules — no JSON/per-node deserialize, absolute spans, native-only single traversal, instance reuse.

Rule.

Never JSON-serialize the AST, and never Deserialize the archive to native nodes per-node in the hot path — rules read the archived form in place via NodeRef<'ast>.
Span is an absolute byte range into Ast.text; never pass source as a separate payload; no node-relative rebasing.
Single-traversal is a native-rule property only. Plugins receive the whole archive once per (file, plugin) and self-traverse; never call a plugin per node.
Config membership lookups use HashSet; precompute outside the file loop.
Share the compiled WASM Module via Arc; reuse Store/Instance per rayon worker (reset between files); the host-written AST is read with access_unchecked (no O(N) re-validation per plugin).

Why. The original design's JSON serialization in the hot path negated the AST's cache locality; per-node boundary crossings and per-plugin revalidation are the other cliffs.

How to apply. If a change adds an allocation/copy/serialize per node, or a host↔guest crossing per node, stop — it is almost certainly wrong. Benchmark the real WASM path.