LineCap

Enforce maximum file line counts in CI.

LineCap is a GitHub Action that checks files against a configurable line limit and fails your build when any file exceeds it. Keep your codebase manageable by catching oversized files before they merge.

Quickstart

- uses: actions/checkout@v4
  with:
    fetch-depth: 0

- uses: BenGlasser/linecap@v1

That's it. By default, LineCap checks newly added files against a 400-line limit.

Inputs

Input	Description	Default
max_lines	Maximum lines allowed per file	400
targets	Comma-separated: new, changed, all, explicit	new
explicit_files	Newline-separated file paths (required when targets includes explicit)
include	Newline-separated glob patterns to include	(all files)
exclude	Newline-separated glob patterns to exclude
diff_base	Base ref/SHA for diff	(auto-detected)
diff_head	Head ref/SHA for diff	(auto-detected)
fail_on_no_git	Fail if git history is unavailable	true

Targets

Target	Description
new	Files added in the diff (PR or push)
changed	Files added, modified, renamed, or copied in the diff
all	All tracked files in the repository
explicit	Files listed in explicit_files input

Targets are combinable — the file set is the union of all selected targets. After computing the union, include globs filter first, then exclude globs remove matches.

Outputs

Output	Description
checked_files	Newline-separated list of files that were checked
offenders	Newline-separated list of files exceeding the limit

Examples

Check newly added files (default)

- uses: BenGlasser/linecap@v1

Check new files + specific files

- uses: BenGlasser/linecap@v1
  with:
    targets: new,explicit
    explicit_files: |
      src/legacy/big-module.ts
      src/legacy/old-controller.ts

Check all tracked files with include/exclude

- uses: BenGlasser/linecap@v1
  with:
    max_lines: '300'
    targets: all
    include: |
      src/**/*.ts
      src/**/*.tsx
    exclude: |
      src/**/*.test.ts
      src/**/*.generated.ts

Check changed files in a PR

- uses: BenGlasser/linecap@v1
  with:
    targets: changed
    max_lines: '500'

Print offenders on failure

- uses: BenGlasser/linecap@v1
  id: linecap
  continue-on-error: true

- if: steps.linecap.outputs.offenders != ''
  run: |
    echo "These files are too long:"
    echo "${{ steps.linecap.outputs.offenders }}"

Full workflow example

name: Lint
on:
  pull_request:
  push:
    branches: [main]

jobs:
  linecap:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v4
        with:
          fetch-depth: 0

      - uses: BenGlasser/linecap@v1
        with:
          max_lines: '400'
          targets: changed

Troubleshooting

"Cannot resolve base commit"

LineCap needs git history to compute diffs for new and changed targets. Make sure you use fetch-depth: 0 in your checkout step:

- uses: actions/checkout@v4
  with:
    fetch-depth: 0

Shallow clones

If you can't use fetch-depth: 0, LineCap will attempt to fetch the required commits automatically. If that fails and fail_on_no_git is true (default), the action will error. Set fail_on_no_git: false to skip diff-based targets when history is unavailable:

- uses: BenGlasser/linecap@v1
  with:
    fail_on_no_git: 'false'
    targets: all

Base/head missing

For pull_request events, base and head are read from the event payload. For push events, base is event.before and head is GITHUB_SHA. You can override both:

- uses: BenGlasser/linecap@v1
  with:
    diff_base: ${{ github.event.pull_request.base.sha }}
    diff_head: ${{ github.event.pull_request.head.sha }}

Permissions

LineCap only needs read access to the repository contents. The default GITHUB_TOKEN permissions are sufficient. No additional permissions are required.

No files checked

If LineCap reports 0 files checked:

• Verify your targets setting matches your use case
• Check that include/exclude patterns aren't filtering out all files
• For new/changed targets, ensure there are actual file changes in the diff
• For explicit targets, verify the file paths exist in the repository

License

MIT