ln-741-linter-configurator

Does:

• Detects which linter stack to configure based on project type
• Checks for existing linter configurations
• Generates appropriate config files from templates
• Installs required dependencies
• Verifies linter runs without errors

Does NOT:

• Configure pre-commit hooks (ln-742 does this)
• Set up test infrastructure (ln-743 does this)
• Modify source code

---

| Technology | Linter | Formatter | Config Files |

|------------|--------|-----------|--------------|

| TypeScript/React | ESLint 9+ (flat config) | Prettier | eslint.config.mjs, .prettierrc |

| .NET | Roslyn Analyzers | dotnet format | .editorconfig, Directory.Build.props |

| Python | Ruff | Ruff (built-in) | ruff.toml or pyproject.toml |

---

Before generating configs, check what already exists.

Files to Check:

| Stack | Config Files | Glob Pattern |

|-------|--------------|--------------|

| TypeScript | ESLint config | eslint.config., .eslintrc |

| TypeScript | Prettier config | .prettierrc, prettier.config. |

| .NET | Editor config | .editorconfig |

| .NET | Build props | Directory.Build.props |

| Python | Ruff config | ruff.toml, pyproject.toml |

Decision Logic:

1. If config exists and is complete: SKIP (inform user)
2. If config exists but incomplete: ASK user to merge or replace
3. If no config exists: CREATE from template

---

Use templates from references/ folder. Customize placeholders based on project.

TypeScript/React:

1. Copy eslint_template.mjs to project root as eslint.config.mjs
2. Copy prettier_template.json as .prettierrc
3. Add scripts to package.json:

- "lint": "eslint ."

- "lint:fix": "eslint . --fix"

- "format": "prettier --write ."

- "format:check": "prettier --check ."

.NET:

1. Copy editorconfig_template.ini as .editorconfig
2. Copy directory_build_props_template.xml as Directory.Build.props
3. Ensure analyzers package reference included

Python:

1. Copy ruff_template.toml as ruff.toml

- OR merge into existing pyproject.toml under [tool.ruff]

1. Add scripts to pyproject.toml or document commands

---

Install required packages for each stack.

TypeScript/React:

```

npm install -D eslint @eslint/js typescript-eslint eslint-plugin-react eslint-plugin-react-hooks eslint-config-prettier prettier

```

> CRITICAL: eslint-config-prettier is REQUIRED to prevent ESLint/Prettier conflicts.

.NET:

• Analyzers configured via Directory.Build.props
• No separate install needed

Python:

```

pip install ruff

# OR with uv:

uv add --dev ruff

```

---

After configuration, verify linter works.

TypeScript:

```bash

npm run lint

npm run format:check

```

Expected: Exit code 0

.NET:

```bash

dotnet format --verify-no-changes

```

Expected: Exit code 0

Python:

```bash

ruff check .

ruff format --check .

```

Expected: Exit code 0

On Failure: Check error output, adjust config, re-verify.

---

> RULE 1: Always include eslint-config-prettier when using ESLint + Prettier together.

> RULE 2: Use ESLint flat config format (eslint.config.mjs), NOT legacy .eslintrc.

> RULE 3: Ruff replaces Black, isort, flake8, and many other Python tools. Do NOT install them separately.

> RULE 4: Never disable strict TypeScript rules without documented reason.

---

• [ ] Appropriate config files created for detected stack
• [ ] Dependencies installed
• [ ] Lint command runs without errors on project source
• [ ] Format command runs without errors
• [ ] No ESLint/Prettier conflicts (eslint-config-prettier installed)
• [ ] User informed of available lint/format commands

---

| File | Purpose |

|------|---------|

| [eslint_template.mjs](references/eslint_template.mjs) | ESLint flat config template |

| [prettier_template.json](references/prettier_template.json) | Prettier config template |

| [editorconfig_template.ini](references/editorconfig_template.ini) | .NET editorconfig template |

| [directory_build_props_template.xml](references/directory_build_props_template.xml) | .NET analyzers template |

| [ruff_template.toml](references/ruff_template.toml) | Python Ruff config template |

| [linter_guide.md](references/linter_guide.md) | Detailed configuration guide |

---

| Error | Cause | Resolution |

|-------|-------|------------|

| ESLint/Prettier conflict | Missing eslint-config-prettier | Install and add to config |

| TypeScript parse errors | Parser version mismatch | Align typescript-eslint with TS version |

| Ruff not found | Not installed | pip install ruff or uv add ruff |

| dotnet format fails | Missing SDK | Install .NET SDK |

---

Version: 2.0.0

Last Updated: 2026-01-10