Linter Autofix Patterns

Quick reference for running linter autofixes across languages.

Autofix Commands

Language	Linter	Autofix Command
TypeScript/JS	biome	npx @biomejs/biome check --write .
TypeScript/JS	biome format	npx @biomejs/biome format --write .
Python	ruff	ruff check --fix .
Python	ruff format	ruff format .
Rust	clippy	cargo clippy --fix --allow-dirty
Rust	rustfmt	cargo fmt
Go	gofmt	gofmt -w .
Go	go mod	go mod tidy
Shell	shellcheck	No autofix (manual only)

Common Fix Patterns

JavaScript/TypeScript (Biome)

Unused imports

// Before
import { useState, useEffect, useMemo } from 'react';
// Only useState used

// After
import { useState } from 'react';

Prefer const

// Before
let x = 5;  // Never reassigned

// After
const x = 5;

Python (Ruff)

Import sorting (I001)

# Before
import os
from typing import List
import sys

# After
import os
import sys
from typing import List

Unused imports (F401)

# Before
import os
import sys  # unused

# After
import os

Line too long (E501)

# Before
result = some_function(very_long_argument_one, very_long_argument_two, very_long_argument_three)

# After
result = some_function(
    very_long_argument_one,
    very_long_argument_two,
    very_long_argument_three,
)

Rust (Clippy)

Redundant clone

// Before
let s = String::from("hello").clone();

// After
let s = String::from("hello");

Use if let

// Before
match option {
    Some(x) => do_something(x),
    None => {},
}

// After
if let Some(x) = option {
    do_something(x);
}

Shell (ShellCheck)

Quote variables (SC2086)

# Before
echo $variable

# After
echo "$variable"

Use $(...) instead of backticks (SC2006)

# Before
result=`command`

# After
result=$(command)

Workflow

1. Run autofix first: ruff check --fix . && ruff format .
2. Check remaining issues: ruff check .
3. Manual fixes for complex cases
4. Verify: re-run linter to confirm clean

When to Escalate

Stop and use different approach when:

• Fix requires understanding business logic
• Multiple files need coordinated changes
• Warning indicates potential bug (not just style)
• Security-related linter rule
• Type error requires interface/API changes