alint

alint (short for agnostic lint) is a language-agnostic linter for repository structure, filenames, and file content rules, with optional auto-fix.

Status: v0.3 ships ~42 rule kinds across ten families, auto-fix with 12 ops, and conditional rules via a bounded expression language. See docs/rules.md for the full catalogue and docs/design/ROADMAP.md for scope per version.

What alint does

alint enforces declarative rules over a repository tree. Rules live in a .alint.yml at the root; alint walks the tree (honoring .gitignore), matches rules against every file and directory, reports violations, and — when you ask — automatically fixes them.

Core capabilities

• ~42 rule kinds across ten families (full reference: docs/rules.md):
  • Existence — file_exists, file_absent, dir_exists, dir_absent.
  • Content — file_content_matches, file_content_forbidden, file_header, file_starts_with, file_ends_with, file_hash, file_max_size, file_is_text, file_is_ascii.
  • Naming — filename_case, filename_regex.
  • Text hygiene — no_trailing_whitespace, final_newline, line_endings, line_max_width, indent_style, max_consecutive_blank_lines.
  • Security / Unicode — no_merge_conflict_markers, no_bidi_controls, no_zero_width_chars.
  • Encoding — no_bom.
  • Structure — max_directory_depth, max_files_per_directory, no_empty_files.
  • Portable metadata — no_case_conflicts, no_illegal_windows_names.
  • Unix metadata — no_symlinks, executable_bit, executable_has_shebang, shebang_has_executable.
  • Git hygiene — no_submodules.
  • Cross-file — pair, for_each_dir, for_each_file, dir_contains, dir_only_contains, unique_by, every_matching_has.
• Auto-fix — 12 file ops covering content edits (trim whitespace, append newline, normalize line endings, strip BOM / bidi / zero-width, collapse blank lines) and path-level changes (create / remove / rename / prepend / append). Preview with alint fix --dry-run. Content-editing ops honour a configurable fix_size_limit (default 1 MiB) that skips oversize files rather than rewriting them.
• Conditional rules — a bounded when: expression language (boolean logic, comparisons, matches regex, in list membership) gates rules on facts evaluated once per run: any_file_exists, all_files_exist, count_files.
• Four output formats — human, json (stable schema), sarif (GitHub Code Scanning), github (inline PR annotations).
• JSON Schema at schemas/v1/config.json for editor autocomplete.
• Official GitHub Action — asamarts/alint@v0.3.0.

Typical use cases

• "Every package in a monorepo has a README.md and a LICENSE*" — dir_contains across packages/*.
• "All Rust source files carry a copyright header; auto-prepend any that don't" — file_header + file_prepend.
• "No stray *.bak or *.swp files in committed history; delete any that slip in" — file_absent + file_remove.
• "Filename case convention enforced per language" — filename_case with when: facts.is_typescript gating.
• "Every module directory has a mod.rs" — for_each_dir with nested file_exists.
• "No two files share a basename across the tree" — unique_by with key: "{basename}".

The full DSL is documented in docs/design/ARCHITECTURE.md.

Non-goals

alint is deliberately not:

• a code / AST linter — use ESLint, Clippy, ruff
• a SAST scanner — use Semgrep, CodeQL
• an IaC scanner — use Checkov, Conftest, tfsec
• a commit-message linter — use commitlint
• a secret scanner — use gitleaks, trufflehog

Scope is the filesystem shape and contents of a repository, not the semantics of the code inside it.

Install

From a tagged release (recommended)

curl -sSL https://raw.githubusercontent.com/asamarts/alint/main/install.sh | bash

Detects platform (Linux / macOS, x86_64 / aarch64), downloads the matching tarball, verifies the SHA-256, and installs to $INSTALL_DIR (default ~/.local/bin). Windows users download the Windows tarball from the Releases page.

From crates.io

cargo install alint

From source

git clone https://github.com/asamarts/alint
cd alint
cargo build --release -p alint
./target/release/alint --help

Quick start

Create a .alint.yml at the root of your repository:

# yaml-language-server: $schema=https://raw.githubusercontent.com/asamarts/alint/main/schemas/v1/config.json
version: 1

facts:
  - id: is_rust
    any_file_exists: [Cargo.toml]

rules:
  - id: readme-exists
    kind: file_exists
    paths: ["README.md", "README"]
    root_only: true
    level: error
    fix:
      file_create:
        content: "# Project\n"

  - id: no-backup-files
    kind: file_absent
    paths: "**/*.{bak,swp}"
    level: warning
    fix:
      file_remove: {}

  - id: components-pascal
    kind: filename_case
    paths: "components/**/*.{tsx,jsx}"
    case: pascal
    level: error
    fix:
      file_rename: {}

  - id: rust-snake
    when: facts.is_rust
    kind: filename_case
    paths: "src/**/*.rs"
    case: snake
    level: error
    fix:
      file_rename: {}

  - id: java-license-header
    kind: file_header
    paths: "**/*.java"
    lines: 20
    pattern: "(?s)Copyright \\(c\\) \\d{4}"
    level: error
    fix:
      file_prepend:
        content: |
          // Copyright (c) 2026 Acme Corp

Then run:

alint check           # run all rules against the current directory
alint fix --dry-run   # preview the auto-fixes that would be applied
alint fix             # apply every fixable violation in place
alint list            # list effective rules
alint explain <id>    # show a rule's definition

Output formats:

alint check --format human    # default; colorized for humans
alint check --format json     # stable, versioned JSON schema
alint check --format sarif    # SARIF 2.1.0 (for GitHub Code Scanning)
alint check --format github   # GitHub Actions workflow commands

Exit codes: 0 no errors; 1 one or more errors; 2 config error; 3 internal error. Warnings do not fail by default — use --fail-on-warning to flip that.

Use in CI

GitHub Actions

Inline PR annotations (default):

- uses: asamarts/alint@v0.3.0

All inputs (all optional):

- uses: asamarts/alint@v0.3.0
  with:
    version: v0.3.0        # alint release tag (default: latest)
    path: .                # directory to lint (default: .)
    format: github         # human | json | sarif | github (default)
    config: |              # extra config path(s), one per line
      .alint.yml
    fail-on-warning: false
    args: ""               # extra CLI args appended verbatim

Upload findings to GitHub Code Scanning:

- uses: asamarts/alint@v0.3.0
  id: alint
  with:
    format: sarif
  continue-on-error: true
- uses: github/codeql-action/upload-sarif@v3
  if: always()
  with:
    sarif_file: ${{ steps.alint.outputs.sarif-file }}

Docs

• ARCHITECTURE.md — rule model, DSL, execution model, crate layout, plugin model.
• ROADMAP.md — scope per version from v0.1 through v1.0.
• CHANGELOG.md — per-version changes, breaking and otherwise.
• docs/benchmarks/METHODOLOGY.md — how benchmarks are measured and published.
• Per-version, per-platform benchmark results under docs/benchmarks/<version>/.

Development

git clone https://github.com/asamarts/alint
cd alint
cargo test --workspace        # 200+ tests; includes end-to-end scenarios
cargo run -- check            # dogfood: alint lints itself
cargo bench -p alint-bench    # criterion micro-benches

End-to-end tests live in crates/alint-e2e/scenarios/ as declarative YAML; adding a new scenario only requires a new file. CLI snapshot tests live in crates/alint/tests/cli/ under trycmd. Property-based invariants are in crates/alint-e2e/tests/invariants.rs.

CI is self-hosted with per-job bash scripts under ci/scripts/ that run locally or in GitHub Actions unchanged. See ci/env.example for runner setup.

License

Dual-licensed under either of:

• Apache License 2.0 (SPDX Apache-2.0)
• MIT License (SPDX MIT)

at your option. Unless you explicitly state otherwise, any contribution intentionally submitted for inclusion in alint shall be dual-licensed as above, without any additional terms or conditions.