dead-code.md

Find and remove dead code from the codebase.

Steps

1. Unused Imports

• Run the linter with unused import detection:
  • TypeScript: tsc --noUnusedLocals --noUnusedParameters --noEmit
  • ESLint: Check for no-unused-vars, no-unused-imports violations.
  • Python: ruff check --select F401 or flake8 --select=F401.
  • Go: The compiler already catches unused imports.
• Remove all unused imports.

2. Unused Exports

• For each exported function, class, or constant, search the codebase for imports of that symbol.
• If a symbol is exported but never imported elsewhere, check if it is part of the public API.
• If it is internal and unused, remove the export and the code.
• Pay attention to dynamic imports and re-exports.

3. Unreachable Code

• Look for code after return, throw, break, or continue statements.
• Find branches that can never be true based on type narrowing or constant conditions.
• Identify functions that are defined but never called.
• Check for commented-out code blocks and remove them.

4. Dead Feature Flags

• Search for feature flags or environment variable checks.
• Identify flags that are always true/false in all environments.
• Remove the dead branch and the flag check.

5. Verify

• Run the full test suite to confirm nothing depends on the removed code.
• Run the build to confirm compilation succeeds.
• Check that no public API contracts were broken if this is a library.

Rules

• Remove code in small, focused commits. One category of dead code per commit.
• If unsure whether code is used, check git blame for when it was last modified. Code untouched for 6+ months with no references is likely dead.
• Do not remove code that is part of a public API without a deprecation period.
• Keep test utilities and fixtures even if they seem unused; they may be needed for future tests.
• Never remove error handling or fallback code just because it has not been triggered yet.