cvs-patch.yaml

name: Generate CVS Patch Per Commit on Main Push

on:
  push:
    branches:
      - main

jobs:
  cvs_patch_and_release:
    runs-on: ubuntu-latest

    steps:
      - name: Checkout code
        uses: actions/checkout@v3
        with:
          fetch-depth: 0 # Checkout all commits

      - name: Set up Git identity
        run: |
          git config --local user.name "GitHub Actions"
          git config --local user.email "actions@github.com"

      - name: Generate patch file
        id: generate_patch
        run: |
          PATCH_DIR="patches"
          mkdir -p "$PATCH_DIR"

          # Check if it's the initial commit (still handle initial commit gracefully)
          if ! git rev-parse --short HEAD~1 > /dev/null 2>&1; then
            echo "Initial commit detected. Skipping patch generation for the first commit."
            echo "patch_file_name=no-patch-generated" >> "$GITHUB_OUTPUT"
            echo "patch_file_path=no-patch-path" >> "$GITHUB_OUTPUT"
            echo "patch_generated=false" >> "$GITHUB_OUTPUT"
          else
            # Generate patch for the range of commits from parent of HEAD to HEAD
            COMMIT_RANGE="HEAD^1..HEAD"
            echo "Commit range for patch: $COMMIT_RANGE"
            git format-patch --no-stat -o "$PATCH_DIR" "$COMMIT_RANGE"
            PATCH_FILE=$(find "$PATCH_DIR" -type f -name "*.patch")
            if [[ -z "$PATCH_FILE" ]]; then
              echo "Info: No patch file generated because no code changes detected in merge (or possibly initial workflow run)."
              echo "patch_file_name=no-patch-generated" >> "$GITHUB_OUTPUT"
              echo "patch_file_path=no-patch-path" >> "$GITHUB_OUTPUT"
              echo "patch_generated=false" >> "$GITHUB_OUTPUT"
              exit 1 # Exit with error to prevent further progress and indicate a problem with workflow
            else
              PATCH_FILE_NAME=$(basename "$PATCH_FILE")
              echo "Patch file generated: $PATCH_FILE_NAME"

              # Get abbreviated commit hash for HEAD
              HEAD_COMMIT_SHORT=$(git rev-parse --short HEAD)
              echo "Abbreviated HEAD commit hash: $HEAD_COMMIT_SHORT"
              
              echo "patch_file_name=$PATCH_FILE_NAME" >> "$GITHUB_OUTPUT"
              echo "patch_file_path=$PATCH_FILE" >> "$GITHUB_OUTPUT"
              echo "patch_generated=true" >> "$GITHUB_OUTPUT"
              echo "head_commit_short=$HEAD_COMMIT_SHORT" >> "$GITHUB_OUTPUT"
            fi
          fi
        shell: /usr/bin/bash -e {0} # Use bash instead of sh

      - name: Create GitHub Release
        if: ${{ steps.generate_patch.outputs.patch_generated == 'true' }} # Conditional release creation
        id: create_release
        uses: softprops/action-gh-release@v2
        env:
          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
        with:
          tag_name: cvs-sync-release-${{ github.run_id }}
          name: CVS Patch Release - Commit ${{ steps.generate_patch.outputs.head_commit_short }}
          body: |
            ## Patch File Generated

            A patch file has been automatically generated from the latest changes merged into the `main` branch.

            1. **Download the attached patch file from this release.**

            **Patch File Name:** ${{ steps.generate_patch.outputs.patch_file_name }}
            **Patch File Path:** ${{ steps.generate_patch.outputs.patch_file_path }}

            2. **Transfer the patch file** to a machine with access to your CVS pserver and your CVS working copy.
            3. **Login to the CVS-capable node.**
            4. **Identify the *next* release to apply:**  Consult your CVS repository for the latest `git-hash-*` tag. The release to apply is the one for the Git commit *after* the commit hash in the latest CVS tag (or the very first release if no `git-hash-*` tags exist yet). **In most cases, you will simply apply the releases in the order they are created.**
            5. **Navigate to the root directory of your CVS working copy** in the terminal.
            6. **Apply the patch using the `patch` command:**

            ```bash
            patch -p1 < ${{ steps.generate_patch.outputs.patch_file_path }}
            ```
            
            7. **Resolve any conflicts** reported by the `patch` command manually in your CVS working copy. Use `cvs update -j <conflicting_revision>` if needed.
            8. **Build and thoroughly test** the build process in the CVS environment after applying the patch.
            9. **Commit the changes to CVS:**
            
               ```bash
               cvs commit -m "Sync from Git - Commit ${{ steps.generate_patch.outputs.head_commit_short }}"
               ```
               
            10. **Crucially, create a CVS tag *immediately* after a *successful* CVS commit:**
            
                ```bash
                cvs tag git-hash-${{ steps.generate_patch.outputs.head_commit_short }}
                ```
                
                **Use the Git commit hash `${{ steps.generate_patch.outputs.head_commit_short }}` from this GitHub Release in the CVS tag name.** This tag is essential for tracking the CVS sync state and identifying the next release to apply.
          draft: false
          prerelease: false
          files: ${{ steps.generate_patch.outputs.patch_file_path }}