midnightntwrk/midnight-expert/quality-check

Run and Interpret Quality Checks

Last verified: 2026-09-17 — compact compile CLI usage and package names/versions checked against the installed toolchain (compiler 0.31.1) + npm (@openzeppelin/compact-simulator@0.3.1, runtime 0.16.0).

This skill is for running checks and fixing failures.

To set up quality tooling from scratch, use midnight-cq:quality-init.

Command Quick Reference

Run commands from the project root. If biome is not on the path, prefix with npx.

How to Read Results

Biome

Each violation uses this format:

path/to/file.ts:line:col rule/name LEVEL description

Example:

src/index.ts:12:5 style/useConst ERROR This variable is never reassigned.

• `rule/name` — maps directly to a rule at biomejs.dev/linter/rules/<rule-name>. Open the URL for the rationale and suggested fix.
• `LEVEL` is always ERROR in Midnight projects (no warnings in CI — see biome.json).
• Format violations say format as the rule and show a unified diff of what Biome expects. Apply with biome check --write.
• Exit code 1 means at least one violation. Exit code 0 means clean.

tsc --noEmit

Each error uses this format:

path/to/file.ts(line,col): error TS#### description

In Midnight projects, tsc errors frequently originate from:

1. Stale Compact compiler output — types in managed/ are regenerated by compact compile. If .compact source changed but managed/ was not recompiled, tsc will report phantom type errors. Fix: run compact compile --skip-zk first, then re-run tsc --noEmit.
2. Missing or wrong imports from `managed/` — the compiler emits named exports; check the generated .d.ts for the exact export name.
3. Strict null / undefined — common when accessing ledger state that may not be initialised yet. Narrow with an explicit guard.

vitest

A failing test shows:

FAIL src/test/MyContract.test.ts
  ● transferOwnership › should fail when called by unauthorized
 
    Error: Ownable: caller is not the owner
 
      at ProxyHandler.<anonymous> (node_modules/@openzeppelin/compact-simulator/dist/...)
      at ...
      at MyContractSimulator.transferOwnership (src/test/simulators/MyContractSimulator.ts:42:5)
      at Object.<anonymous> (src/test/MyContract.test.ts:67:7)

Reading the trace:

• Error message — maps directly to a assert string in the .compact source. Search the contract for the literal message to find the failing assertion.
• Simulator file + line — shows which user-friendly method triggered the circuit.
• Test file + line — the exact expect(...) or method call that failed.
• Ignore the deep ProxyHandler frames in node_modules — they are internal simulator machinery and carry no debugging signal.
• A test that expected a throw but didn't get one reports Received function did not throw. Check whether the circuit path that should reject was actually reached.

Common Quick Fixes

Not For

• Setting up quality tooling from scratch → use midnight-cq:quality-init
• Writing new Compact contract tests → use midnight-cq:compact-testing
• Writing new DApp E2E tests → use midnight-cq:dapp-testing

Reference Files