Merge branch 'cw/ci-whitespace' into maint-2.39

CI updates.  We probably want a clean-up to move the long shell
script embedded in yaml file into a separate file, but that can
come later.

* cw/ci-whitespace:
  ci (check-whitespace): move to actions/checkout@v3
  ci (check-whitespace): add links to job output
  ci (check-whitespace): suggest fixes for errors

.github/workflows/check-whitespace.yml

@@ -13,38 +13,73 @@ jobs:
   check-whitespace:
     runs-on: ubuntu-latest
     steps:
-    - uses: actions/checkout@v2
+    - uses: actions/checkout@v3
       with:
         fetch-depth: 0
 
     - name: git log --check
       id: check_out
       run: |
-        log=
+        baseSha=${{github.event.pull_request.base.sha}}
+        problems=()
         commit=
-        while read dash etc
+        commitText=
+        commitTextmd=
+        goodparent=
+        while read dash sha etc
         do
           case "${dash}" in
           "---")
-            commit="${etc}"
+            if test -z "${commit}"
+            then
+              goodparent=${sha}
+            fi
+            commit="${sha}"
+            commitText="${sha} ${etc}"
+            commitTextmd="[${sha}](https://github.com/${{ github.repository }}/commit/${sha}) ${etc}"
             ;;
           "")
             ;;
           *)
             if test -n "${commit}"
             then
-              log="${log}\n${commit}"
+              problems+=("1) --- ${commitTextmd}")
               echo ""
-              echo "--- ${commit}"
+              echo "--- ${commitText}"
+              commit=
             fi
-            commit=
-            log="${log}\n${dash} ${etc}"
-            echo "${dash} ${etc}"
+            case "${dash}" in
+            *:[1-9]*:) # contains file and line number information
+              dashend=${dash#*:}
+              problems+=("[${dash}](https://github.com/${{ github.repository }}/blob/${{github.event.pull_request.head.ref}}/${dash%%:*}#L${dashend%:}) ${sha} ${etc}")
+              ;;
+            *)
+              problems+=("\`${dash} ${sha} ${etc}\`")
+              ;;
+            esac
+            echo "${dash} ${sha} ${etc}"
             ;;
           esac
-        done <<< $(git log --check --pretty=format:"---% h% s" ${{github.event.pull_request.base.sha}}..)
+        done <<< $(git log --check --pretty=format:"---% h% s" ${baseSha}..)
 
-        if test -n "${log}"
+        if test ${#problems[*]} -gt 0
         then
+          if test -z "${commit}"
+          then
+            goodparent=${baseSha: 0:7}
+          fi
+          echo "🛑 Please review the Summary output for further information."
+          echo "### :x: A whitespace issue was found in one or more of the commits." >$GITHUB_STEP_SUMMARY
+          echo "" >>$GITHUB_STEP_SUMMARY
+          echo "Run these commands to correct the problem:" >>$GITHUB_STEP_SUMMARY
+          echo "1. \`git rebase --whitespace=fix ${goodparent}\`" >>$GITHUB_STEP_SUMMARY
+          echo "1. \`git push --force\`" >>$GITHUB_STEP_SUMMARY
+          echo " " >>$GITHUB_STEP_SUMMARY
+          echo "Errors:" >>$GITHUB_STEP_SUMMARY
+          for i in "${problems[@]}"
+          do
+            echo "${i}" >>$GITHUB_STEP_SUMMARY
+          done
+
           exit 2
         fi