Strict Clippy Check

Strict Clippy Check Skill

Purpose

Enforces Pierre's zero-tolerance code quality policy using Clippy with strict lints. All warnings are treated as errors per CLAUDE.md standards.

CLAUDE.md Compliance

• ✅ Enforces zero tolerance for unwrap(), expect(), panic!()
• ✅ Validates no anyhow::anyhow!() usage
• ✅ Checks for proper error handling patterns
• ✅ Enforces code quality standards

Usage

Run this skill:

• Before every commit
• Before creating pull requests
• After refactoring
• During code reviews

Prerequisites

• Rust toolchain installed
• Clippy component (rustup component add clippy)

Commands

Standard Strict Check

# Run Clippy with strict lints (Cargo.toml configuration)
cargo clippy --all-targets --all-features -- -D warnings

Explicit Strict Check (Legacy)

# Run with all lint groups enabled
cargo clippy --all-targets --all-features -- \
  -W clippy::all \
  -W clippy::pedantic \
  -W clippy::nursery \
  -D warnings

Specific Lint Categories

# Check only error handling patterns
cargo clippy --all-targets -- \
  -D clippy::unwrap_used \
  -D clippy::expect_used \
  -D clippy::panic

# Check performance lints
cargo clippy --all-targets -- \
  -W clippy::clone_on_copy \
  -W clippy::redundant_clone

Fix Auto-Fixable Issues

# Apply automatic fixes (use with caution)
cargo clippy --fix --all-targets --allow-dirty -- -D warnings

# Preview fixes without applying
cargo clippy --fix --all-targets --allow-dirty --dry-run -- -D warnings

Linting Configuration

Pierre uses Cargo.toml lints configuration (eliminates need for bash script flags):

[lints.clippy]
all = { level = "deny", priority = -1 }
pedantic = { level = "deny", priority = -1 }
nursery = { level = "deny", priority = -1 }

# Critical error handling
unwrap_used = "deny"
expect_used = "deny"
panic = "deny"

Common Issues & Fixes

Issue: unwrap() detected

// ❌ Bad
let value = some_option.unwrap();

// ✅ Good
let value = some_option.ok_or(AppError::NotFound)?;

Issue: expect() detected

// ❌ Bad
let config = load_config().expect("Failed to load config");

// ✅ Good
let config = load_config()
    .map_err(|e| AppError::ConfigError(e.to_string()))?;

Issue: panic!() detected

// ❌ Bad
if user_id.is_none() {
    panic!("User ID required");
}

// ✅ Good
let user_id = user_id.ok_or(AppError::MissingUserId)?;

Issue: anyhow::anyhow!() detected

// ❌ Bad (CLAUDE.md violation)
return Err(anyhow::anyhow!("Database connection failed"));

// ✅ Good (use structured errors)
return Err(AppError::DatabaseError(
    DatabaseError::ConnectionFailed
));

Issue: Cast warnings

// ❌ Might truncate
let small = large_value as u8;

// ✅ Safe conversion
let small = u8::try_from(large_value)
    .map_err(|_| AppError::ConversionError)?;

Issue: Missing documentation

// ❌ No docs
pub fn calculate_vdot(distance: f64, time: f64) -> f64 { }

// ✅ Documented
/// Calculates VDOT (running performance metric) using Daniels' formula
///
/// # Arguments
/// * `distance` - Distance in meters
/// * `time` - Time in seconds
///
/// # Returns
/// VDOT score (typically 20-85)
///
/// # Errors
/// Returns `AlgorithmError` if inputs are invalid
pub fn calculate_vdot(distance: f64, time: f64) -> Result<f64, AlgorithmError> { }

Allowed Exceptions

Per CLAUDE.md, certain patterns are allowed in specific contexts:

Test Files

// Allowed in tests/bin with "// Safe:" comment
// Safe: Test setup with known valid values
let config = load_test_config().unwrap();

Binary Files

// Allowed in src/bin/ with justification
// Safe: CLI application, error printed to stderr
let args = Args::parse().expect("Failed to parse args");

Integration with CI/CD

Clippy runs in GitHub Actions:

# .github/workflows/rust.yml
- name: Clippy
  run: cargo clippy --all-targets --all-features -- -D warnings

Success Criteria

• ✅ Zero Clippy warnings
• ✅ All error handling uses Result<T, E>
• ✅ No unwrap() in production code (src/)
• ✅ No panic!() in production code
• ✅ No anyhow::anyhow!() anywhere
• ✅ Public APIs documented

Pre-Commit Integration

Install git hooks:

./scripts/setup-git-hooks.sh

This runs Clippy automatically before commits.

Troubleshooting

Issue: Too many warnings, can't fix all at once

# Focus on critical issues first
cargo clippy --all-targets -- \
  -D clippy::unwrap_used \
  -D clippy::expect_used \
  -D clippy::panic

Issue: False positive in generated code

# Suppress in specific context only (must justify)
#[allow(clippy::specific_lint)]  // Justification: generated code

Issue: Lint not recognized

# Update Rust/Clippy
rustup update
rustup component add clippy

Related Files

• Cargo.toml - Lint configuration (lines 141-213)
• scripts/lint-and-test.sh - Combined linting + testing
• scripts/architectural-validation.sh - Pattern validation

Related Skills

• validate-architecture - Architectural pattern validation
• check-no-secrets - Secret detection