git-auto-comment/README.md

PR Commenter Diff-Aware Action

A GitHub/Gitea Action to automatically post comments to pull requests based on a git diff. Supports:

• Inline comments per changed line
• Multiline comment templates
• Cross-platform support (GitHub and Gitea)
• Diff-aware commenting, automatically detecting added lines
• Default values for repository info
• Optional diff input — can post general PR comments without a diff
• Remote URL usage for Gitea Actions

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Features

• GitHub & Gitea support: Works seamlessly on both platforms.
• Diff-aware: Parses a git diff to determine which lines were added.
• Inline comments: Comments appear directly on changed lines in PRs.
• Multiline templates: Supports {line} for a single line and {lines} for all added lines in a file.
• Optional diff: If no diff is provided, posts a general PR comment.
• Default repository values: repo_name, repo_owner, and api_url default to GitHub environment variables if not provided.
• Remote URL usage: Can reference the action directly from a Git repository URL for Gitea.

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Inputs

Input	Description	Required	Default
platform	Target platform: github or gitea	yes	github
token	API token for authentication	yes	-
api_url	Gitea API URL (only required for Gitea, e.g., https://gitea.example.com/api/v1)	no	${{ github.api_url }}
repo_owner	Repository owner (user/org)	no	${{ github.repository_owner }}
repo_name	Repository name	no	${{ github.repository }}
pr_index	PR number (GitHub) or index (Gitea)	yes	-
diff	Git diff to parse (optional). If empty, posts only a general PR comment.	no	-
comment_template	Multiline template for comment body. Use placeholders {line} and {lines}	no	Auto-comment: changed line -> {line}

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Example Usage

GitHub PR

jobs:
  comment-pr-diff:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v3

      - name: Generate git diff
        id: gitdiff
        run: |
          git fetch origin main
          git diff origin/main > diff.txt

      - name: Post diff-aware comments to GitHub PR
        uses: "https://gitea.example.com/your-org/pr-commenter-action@main"
        with:
          platform: github
          token: ${{ secrets.GITHUB_TOKEN }}
          pr_index: ${{ github.event.pull_request.number }}
          diff: ${{ steps.gitdiff.outputs.diff }}
          comment_template: |
            Auto-comment on file:
            ---
            Changed line: {line}
            Full added lines in this file:
            {lines}

Gitea PR

jobs:
  comment-pr-diff:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v3

      - name: Generate git diff
        id: gitdiff
        run: |
          git fetch origin main
          git diff origin/main > diff.txt

      - name: Post diff-aware comments to Gitea PR
        uses: "https://gitea.example.com/your-org/pr-commenter-action@main"
        with:
          platform: gitea
          token: ${{ secrets.GITEA_TOKEN }}
          api_url: "https://gitea.example.com/api/v1"
          pr_index: 42
          diff: ${{ steps.gitdiff.outputs.diff }}
          comment_template: |
            Auto-comment on file:
            ---
            Changed line: {line}
            Full added lines in this file:
            {lines}