Try to validate commit headers.

.github/scripts/CommitHeaderChecker.java

@@ -0,0 +1,78 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+import java.io.IOException;
+import java.net.URI;
+import java.net.http.HttpClient;
+import java.net.http.HttpRequest;
+import java.net.http.HttpResponse;
+import java.util.ArrayList;
+import java.util.List;
+
+public class CommitHeaderChecker {
+
+    //  java CommitHeaderChecker.java https://github.com/apache/netbeans/pull/${{ github.event.number }}
+    public static void main(String[] args) throws IOException, InterruptedException {
+
+        if (args.length != 1 || !args[0].startsWith("https://github.com/")) {
+            throw new IllegalArgumentException("PR URL expected");
+        }
+
+        HttpClient client = HttpClient.newBuilder().followRedirects(HttpClient.Redirect.ALWAYS).build();
+        HttpRequest request = HttpRequest.newBuilder(URI.create(args[0]+".patch")).build();
+
+        // https://openjdk.org/jeps/461 nice usecase for gatherers
+        List<String> headers = client.send(request, HttpResponse.BodyHandlers.ofLines()).body()
+                .filter(l -> l.startsWith("From: ") || l.startsWith("Date: ") || l.startsWith("Subject: "))
+                .toList();
+
+        record Commit(String from, String date, String subject) {}
+
+        List<Commit> commits = new ArrayList<>();
+        for (int i = 0; i < headers.size()-2; i++) {
+            if (headers.get(i).startsWith("From: ") && headers.get(i+1).startsWith("Date: ") && headers.get(i+2).startsWith("Subject: ")) {
+                commits.add(new Commit(headers.get(i), headers.get(i+1), headers.get(i+2)));
+                i+=2;
+            }  
+        }
+
+        boolean green = true;
+        System.out.println("checking "+commits.size()+" commit(s)");
+        for (int i = 0; i < commits.size(); i++) {
+            Commit commit = commits.get(i);
+            int start = commit.from.indexOf("<");
+            int end = commit.from.indexOf(">");
+            if (start != -1 && end != -1) {
+                String mail = commit.from.substring(start+1, end);
+                if (mail.contains("@") && !mail.contains("noreply") && !mail.contains("localhost")) {
+                    String author = commit.from.substring(6, start).strip();
+                    if (author.contains(" ")) { // single word author -> probably the nickname/username/root etc
+                        continue;
+                    }
+                }
+            }
+            System.out.println("::error::invalid email or author in commit#"+i+" '"+commit.from+"'");
+            green = false;
+        }
+        System.out.println("done");
+        if (!green) {
+            System.exit(1);
+        }
+    }
+}

.github/workflows/main.yml

@@ -269,7 +269,7 @@ jobs:
       ANT_OPTS: -Dmetabuild.jsonurl=https://raw.githubusercontent.com/apache/netbeans-jenkins-lib/master/meta/netbeansrelease.json
     strategy:
       matrix:
-        java: [ '11' ]
+        java: [ '21' ]
     steps:
 
       - name: Set up JDK ${{ matrix.java }} 
@@ -285,11 +285,10 @@ jobs:
           persist-credentials: false
           submodules: false
           show-progress: false
-          fetch-depth: 10
 
-      - name: Print last 10 Commits
+      - name: Check Commit Headers
         if: ${{ github.event_name == 'pull_request' && !cancelled() }}
-        run: git log --oneline -n10 --pretty=format:'%h %an [%ae] %s'
+        run: java .github/scripts/CommitHeaderChecker.java https://github.com/apache/netbeans/pull/${{ github.event.number }}
 
       - name: Check line endings and verify RAT report
         if: ${{ !cancelled() }}