ci/tag-maintainers: refactor managing reviewers

Move to separate script that looks at history of requests to determine
who needs to be removed. We will not remove reviews from those who were
manually requested.

.github/workflows/tag-maintainers.yml

@@ -73,79 +73,23 @@ jobs:
 
           echo "maintainers=$MAINTAINERS_LIST" >> "$GITHUB_OUTPUT"
 
-      # Get lists of existing reviewers to avoid duplicates.
-      - name: Get current reviewers
-        id: current-reviewers
-        env:
-          GH_TOKEN: ${{ steps.app-token.outputs.token || secrets.GITHUB_TOKEN }}
-          PR_NUM: ${{ github.event.pull_request.number }}
-          REPO: ${{ github.repository }}
-        run: |
-          PENDING_REVIEWERS=$(gh pr view "$PR_NUM" --json reviewRequests --jq '.reviewRequests[].login')
-          PAST_REVIEWERS=$(gh api "repos/$REPO/pulls/$PR_NUM/reviews" --jq '.[].user.login')
-          USERS_TO_EXCLUDE=$(printf "%s\n%s" "$PENDING_REVIEWERS" "$PAST_REVIEWERS" | sort -u)
-
-          {
-            echo "pending_reviewers<<EOF"
-            echo "$PENDING_REVIEWERS"
-            echo EOF
-            echo "users_to_exclude<<EOF"
-            echo "$USERS_TO_EXCLUDE"
-            echo EOF
-          } >> $GITHUB_OUTPUT
-
-          echo "Current pending reviewers: $PENDING_REVIEWERS"
-          echo "Complete list of users to exclude: $USERS_TO_EXCLUDE"
-
-      # Filter the maintainer list to only include repository collaborators.
-      # You can only request reviews from users with at least triage permissions.
-      - name: Check maintainer collaborator status
-        id: check-collaborators
+      # Manage reviewers
+      - name: Manage reviewers
         env:
           GH_TOKEN: ${{ steps.app-token.outputs.token || secrets.GITHUB_TOKEN }}
+          OWNER: ${{ github.repository_owner }}
+          REPO: ${{ github.event.repository.name }}
+          PR_NUMBER: ${{ github.event.pull_request.number }}
+          PR_AUTHOR: ${{ github.event.pull_request.user.login }}
           MAINTAINERS: ${{ steps.extract-maintainers.outputs.maintainers }}
-          USERS_TO_EXCLUDE: ${{ steps.current-reviewers.outputs.users_to_exclude }}
-          REPO: "${{ github.repository }}"
+          CHANGED_FILES: ${{ steps.changed-files.outputs.changed_files }}
+          BOT_NAME: ${{ steps.app-token.outputs.app-slug || 'github-actions' }}
         run: |
-          NEW_REVIEWERS=()
-
-          # If there are no maintainers, exit early.
-          if [[ -z "$MAINTAINERS" ]]; then
-            echo "No maintainers to check."
-            echo "new_reviewers=" >> "$GITHUB_OUTPUT"
-            exit 0
-          fi
-
-          for MAINTAINER in $MAINTAINERS; do
-            if echo "$USERS_TO_EXCLUDE" | grep -q -w "$MAINTAINER"; then
-              echo "$MAINTAINER is already involved in the review, skipping."
-              continue
-            fi
-
-            echo "Checking if $MAINTAINER is a collaborator..."
-            if gh api "/repos/$REPO/collaborators/$MAINTAINER" --silent; then
-              echo "User $MAINTAINER is a collaborator, adding to new reviewers list."
-              NEW_REVIEWERS+=("$MAINTAINER")
-            else
-              echo "User $MAINTAINER is not a repository collaborator, skipping."
-            fi
-          done
-
-          NEW_REVIEWERS_LIST=$(printf "%s " "${NEW_REVIEWERS[@]}")
-          echo "new_reviewers=${NEW_REVIEWERS_LIST% }" >> "$GITHUB_OUTPUT"
-          echo "New reviewers to add: ${NEW_REVIEWERS_LIST% }"
-
-      # Add the new, filtered list of maintainers as reviewers to the PR.
-      - name: Add new reviewers
-        env:
-          GH_TOKEN: ${{ steps.app-token.outputs.token || secrets.GITHUB_TOKEN }}
-          NEW_REVIEWERS: ${{ steps.check-collaborators.outputs.new_reviewers }}
-          PR_NUM: ${{ github.event.pull_request.number }}
-        run: |
-          if [[ -n "$NEW_REVIEWERS" ]]; then
-            REVIEWERS_CSV=$(echo "$NEW_REVIEWERS" | tr ' ' ',')
-            echo "Requesting reviews from: $REVIEWERS_CSV"
-            gh pr edit "$PR_NUM" --add-reviewer "$REVIEWERS_CSV"
-          else
-            echo "No new reviewers to add."
-          fi
+          ./ci/tag-maintainers/manage-reviewers.py \
+            --owner "$OWNER" \
+            --repo "$REPO" \
+            --pr-number "$PR_NUMBER" \
+            --pr-author "$PR_AUTHOR" \
+            --current-maintainers "$MAINTAINERS" \
+            --changed-files "$CHANGED_FILES" \
+            --bot-user-name "$BOT_NAME"