Fallow - Codebase Health

Version updated for https://github.com/fallow-rs/fallow to version v2.7.0.

  • This action is used across all versions by 1 repositories.

Action Type

This is a Composite action.

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Action Summary

This GitHub Action, Fallow, is a Rust-native tool for analyzing TypeScript and JavaScript codebases to identify dead code, duplicated code, and complexity hotspots. It automates the detection of unused exports, dependencies, and files, highlights duplicate and overly complex code, and provides actionable insights to improve code quality. With sub-second performance and zero configuration, it helps developers streamline refactoring and maintain cleaner, more efficient codebases.

What’s Changed

Features

Structured fix suggestions in JSON output

Every issue in --format json output now includes an actions array with machine-actionable remediation hints. AI agents and tooling can programmatically determine how to fix each issue without understanding fallow’s internals.

{
  "path": "src/utils.ts",
  "export_name": "helperFn",
  "line": 10,
  "actions": [
    {
      "type": "remove-export",
      "auto_fixable": true,
      "description": "Remove the `export` keyword from the declaration"
    },
    {
      "type": "suppress-line",
      "auto_fixable": false,
      "description": "Suppress with an inline comment above the line",
      "comment": "// fallow-ignore-next-line unused-export"
    }
  ]
}
  • 14 fix action types in kebab-case (remove-export, delete-file, remove-dependency, remove-enum-member, remove-class-member, resolve-import, install-dependency, remove-duplicate, move-to-dev, refactor-cycle)
  • auto_fixable flag on every action — true means fallow fix handles it automatically
  • Optional note field on non-auto-fixable items explaining why manual review is needed
  • Context-aware suppress — inline comments for source-level issues, add-to-config with concrete package name for dependency-level issues
  • Re-export warnings — remove-export actions on re-exported symbols include a note about verifying public API surface
  • scope: "per-location" on duplicate_exports suppress to signal multi-file scope
  • No schema version bump (additive change)

Pre-commit hook setup (fallow init --hooks)

Scaffold a git pre-commit hook that catches dead code before it merges.

fallow init --hooks                  # auto-detect base branch
fallow init --hooks --base develop   # use custom base branch
  • Hook manager detection: husky > lefthook > bare .git/hooks
  • Binary guard: skips gracefully if fallow is not installed
  • Auto-detects default branch via git symbolic-ref
  • Input validation on --base prevents shell injection
  • Success message includes git commit --no-verify for bypass

Full Changelog: https://github.com/fallow-rs/fallow/compare/v2.6.0...v2.7.0