ci: write up most parts

.github/workflows/validate-renovate.yml

@@ -6,18 +6,51 @@ on:
       - 'renovate.json'
       - '.github/workflows/validate-renovate.yml'
 
+permissions:
+  contents: read
+  issues: write
+
 jobs:
   actionlint:
     name: actionlint with reviewdog
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@v4
       - name: run lint
+        id: lint
         run: |
           # renovate: npm:renovate
           ver="37.291.0"
           # pinned on exact version
           package="renovate@=$ver"
           echo "npx: $(npx --version)"
           echo "installing: $package..."
-          npx --yes --package "$package" -- renovate-config-validator --strict
+          H="$(mktemp)"
+          
+          # let's do main part, but avoid pipefail
+          (npx --yes --package "$package" -- renovate-config-validator --strict || true)\
+            | ruby -e 'File.open(ENV[?H], ?w) {|r| while gets; puts $_; $> = r if $_.chomp == "WARN: Config migration necessary" ;end; }'
+          
+          # init and extract
+          OLD="$(mktemp)"
+          mv "$OLD" "${OLD}.old.txt"
+          NEW="$(mktemp)"
+          mv "$NEW" "${NEW}.new.txt"
+          jq -rs '.old' < "$H" > "$OLD"
+          jq -rs '.new' < "$H" > "$NEW"
+          
+          DIFF_TO_BE_REPORTED="$(mktemp)"
+          mv "$DIFF_TO_BE_REPORTED" "${DIFF_TO_BE_REPORTED}.diff"
+          git diff --no-index "$OLD" "$NEW" >> "$DIFF_TO_BE_REPORTED"
+      - name: report diff
+        env:
+          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+          DIFF_TEXT: ${{ steps.lint.outputs.DIFF }}
+          URL: ${{ github.event.pull_request.html_url }}
+        run:
+          COMMENT_BUFFER="$(mktemp)"
+
+          printf "I'm sorry, but this config should be migrated. Please apply following patch file to proceed:" >> "$COMMENT_BUFFER"
+          cat "$DIFF_TO_BE_REPORTED" >> "$COMMENT_BUFFER"
+
+          gh pr comment -F "$COMMENT_BUFFER" "${URL}"