✅ Fast Conventional Commit Linter

A blazing-fast, dependency-free GitHub Action that lints Pull Request titles and commit messages against the Conventional Commits specification.

Instead of downloading heavy Node.js runtimes (npm install), this action executes natively in milliseconds using built-in Bash regex matching.

✨ Features

• ⚡️ Instant Execution: Native composite action means zero Docker/Node.js startup time.
• 🤖 Bot Evader: Automatically ignores PRs created by dependabot, renovate, and other [bot] accounts to prevent unnecessary CI failures.
• 🛠️ Configurable Types: Easily add your own custom commit types without having to write complex Regex.
• 💥 Breaking Change Support: Fully supports the ! syntax (e.g., feat(api)!: breaking change).
• 📝 Multi-linting: Can lint just the PR title, or every individual commit message in the PR simultaneously.

📥 Inputs

Input	Description	Required	Default
pr_title	The PR title to validate.	No	${{ github.event.pull_request.title }}
commit_messages	Newline-separated list of commits to check.	No	""
allowed_types	Comma-separated list of valid commit types.	No	feat,fix,docs,style,refactor,perf,test,build,ci,chore,revert
custom_regex	Completely override the validation regex.	No	""
ignore_bots	Automatically skip validation for bot accounts.	No	true

💡 Example Inputs & Outputs

Here is how the action behaves under different scenarios:

Example 1: Valid PR Title (Default Settings)

Input:

with:
  pr_title: "feat(auth): add JWT login support"

Output (Action passes):

=== Fast Conventional Commit Linter ===
Using conventional commit regex with types: [feat,fix,docs,style,refactor,perf,test,build,ci,chore,revert]
✓ Valid PR Title: "feat(auth): add JWT login support"

=== Validation Passed! ===

Example 2: Invalid PR Title

Input:

with:
  pr_title: "Added login support"

Output (Action fails and blocks the PR):

=== Fast Conventional Commit Linter ===
Using conventional commit regex with types: [feat,fix,docs,style,refactor,perf,test,build,ci,chore,revert]
✖ Invalid PR Title: "Added login support"

=== Validation Failed ===
Expected format: <type>[optional scope][!]: <description>
Example 1: feat(api): add new authentication endpoint
Example 2: fix!: breaking change to database schema
Allowed types: feat,fix,docs,style,refactor,perf,test,build,ci,chore,revert
Error: Process completed with exit code 1.

Example 3: Custom Allowed Types (e.g., adding wip)

Input:

with:
  pr_title: "wip(ui): draft new dashboard layout"
  allowed_types: "feat,fix,wip"

Output (Action passes):

=== Fast Conventional Commit Linter ===
Using conventional commit regex with types: [feat,fix,wip]
✓ Valid PR Title: "wip(ui): draft new dashboard layout"

=== Validation Passed! ===

Example 4: Validating Multiple Commits

Input:

with:
  pr_title: ""
  commit_messages: |
    fix: resolve memory leak in worker
    chore: update npm dependencies

Output (Action passes):

=== Fast Conventional Commit Linter ===
Using conventional commit regex with types: [feat,fix,docs,style,refactor,perf,test,build,ci,chore,revert]

Checking individual commit messages...
✓ Valid Commit: "fix: resolve memory leak in worker"
✓ Valid Commit: "chore: update npm dependencies"

=== Validation Passed! ===

Example 5: Bot Auto-Ignore Triggered

Input: (Triggered by Dependabot opening a PR with a non-conventional title)

with:
  pr_title: "Bump express from 4.18.1 to 4.18.2"
  ignore_bots: "true"

Output (Action passes without validating the title):

=== Fast Conventional Commit Linter ===
✓ Skipping validation for automated bot account: dependabot[bot]