codeowner_assignment.yaml

name: Codeowner assignment

on: [pull_request]

jobs:
  codeowner_assignment:
    name: Codeowner assignment
    runs-on: ubuntu-latest
    permissions:
      contents: write
      pull-requests: write

    steps:
      - uses: actions/checkout@v4
      
      - uses: actions/create-github-app-token@v2.2.1
        id: token
        with:
          app-id: ${{ vars.CODEOWNER_ASSIGNMENT_GITHUB_APP_ID }}
          private-key: ${{ secrets.CODEOWNER_ASSIGNMENT_PRI_KEY }}
          owner: ${{ github.repository_owner }}
          repositories: |
            sentry-docs

      - name: Parse CODEOWNERS and assign reviewers
        id: assign-reviewers
        env:
          PR_NUMBER: ${{ github.event.number }}
          GH_TOKEN: ${{ steps.token.outputs.token }}
        run: |
          # locate CODEOWNERS file exists
          if [[ -f .github/CODEOWNERS ]]; then
            codeowner_path=".github/CODEOWNERS"
          elif [[ -f CODEOWNERS ]]; then
            codeowner_path="CODEOWNERS"
          else
            echo "CODEOWNERS file not found, skipping."
            exit 0
          fi

          # Get changed files in the PR
          CHANGED_FILES=$(gh pr view $PR_NUMBER --json files --jq '.files[].path')

          echo "----------------------------------------"
          echo "Changed files:"
          echo "$CHANGED_FILES" | tr ' ' '\n' | sed 's/^/- /'
          echo "----------------------------------------"
          
          # Get existing reviewers
          # merge reqeusted teams and users into a single array
          REQUESTED_REVIEWERS=$(gh pr view $PR_NUMBER --json reviewRequests --jq '[.reviewRequests[] | if .__typename == "Team" then .slug else .login end]')
          echo "Requested reviewers:"
          echo "$REQUESTED_REVIEWERS" | tr ' ' '\n' | sed 's/^/- /'
          echo "----------------------------------------"

          # Parse CODEOWNERS and find commented lines
          # Add newline to the end of the file if it doesn't have one, otherwise sed will not read the last line
          sed -i -e '$a\' $codeowner_path
          
          while read -r LINE; do
            # Skip lines that are not commented, GitHub will take care of un-commented lines
            if [[ ! "$LINE" =~ ^# ]]; then continue; fi

            # Extract pattern and reviewer from the commented line
            PATTERN=$(echo "$LINE" | sed -E 's/^#\s*([^@]+).*$/\1/' | xargs)
            # Capture both individual users and GitHub teams reviewers that have "/" in the name
            REVIEWERS=$(echo "$LINE" | grep -o "@[a-zA-Z0-9_-]\+\(/[a-zA-Z0-9_-]\+\)\?" | tr '\n' ' ' | xargs)

            # Skip if no reviewers found
            if [[ -z "$REVIEWERS" ]]; then
              continue
            fi

            # Convert pattern to a regex for matching
            REGEX_PATTERN=$(echo "$PATTERN" | sed -e 's/\./\\./g' -e 's/\*/.*/g' -e 's/\?/./g' -e 's|^/||')
            
            # Match changed files to the pattern
            for FILE in $CHANGED_FILES; do
              # For glob patterns(e.g. "**/"), use a different matching approach
              if [[ "$PATTERN" == *"*"* ]]; then
                # Special handling for **/ pattern
                if [[ "$PATTERN" == "**/"* ]]; then
                  # Get the filename part after **/
                  FILENAME=${PATTERN#**/}
                  # Match either the filename directly or with any path prefix
                  if [[ "$FILE" == "$FILENAME" ]] || [[ "$FILE" == */"$FILENAME" ]]; then
                    echo "File $FILE matches glob pattern $PATTERN"
                    # Assign each reviewer
                    for REVIEWER in $REVIEWERS; do
                      # Remove @ symbol from reviewer name
                      REVIEWER_NAME=${REVIEWER#@}
                      if [[ "$REQUESTED_REVIEWERS" == *"$REVIEWER_NAME"* ]]; then
                        echo " - $REVIEWER_NAME is already a requested reviewer, skipping"
                      else
                        echo " - Assigning $REVIEWER_NAME to review changes in $FILE"
                        gh pr edit $PR_NUMBER --add-reviewer "$REVIEWER_NAME"
                      fi
                    done
                  fi
                else
                  # Convert other glob patterns to regex for matching
                  GLOB_PATTERN=$(echo "$PATTERN" | sed -e 's/\./\\./g' -e 's/\*/.*/g' -e 's/\?/./g')
                  if [[ "$FILE" =~ $GLOB_PATTERN ]]; then
                    echo "File $FILE matches glob pattern $PATTERN"
                    # Assign each reviewer
                    for REVIEWER in $REVIEWERS; do
                      # Remove @ symbol from reviewer name
                      REVIEWER_NAME=${REVIEWER#@}
                      if [[ "$REQUESTED_REVIEWERS" == *"$REVIEWER_NAME"* ]]; then
                        echo " - $REVIEWER_NAME is already a requested reviewer, skipping"
                      else
                        echo " - Assigning $REVIEWER_NAME to review changes in $FILE"
                        gh pr edit $PR_NUMBER --add-reviewer "$REVIEWER_NAME"
                      fi
                    done
                  fi
                fi
              else
                # Original directory matching logic
                if [[ "$FILE" == ${REGEX_PATTERN}* ]]; then
                  echo "File $FILE matches pattern $PATTERN"
                  # Assign each reviewer
                  for REVIEWER in $REVIEWERS; do
                    # Remove @ symbol from reviewer name
                    REVIEWER_NAME=${REVIEWER#@}
                    if [[ "$REQUESTED_REVIEWERS" == *"$REVIEWER_NAME"* ]]; then
                      echo " - $REVIEWER_NAME is already a requested reviewer, skipping"
                    else
                      echo " - Assigning $REVIEWER_NAME to review changes in $FILE"
                      gh pr edit $PR_NUMBER --add-reviewer "$REVIEWER_NAME"
                    fi
                  done
                fi
              fi
            done
          done < $codeowner_path