Merge pull request #2726 from Vlatombe/JENKINS-41511

[JENKINS-41511] Don't try to set slaveAgentPort when it is enforced

core/src/main/java/hudson/security/GlobalSecurityConfiguration.java

@@ -79,7 +79,7 @@ public class GlobalSecurityConfiguration extends ManagementLink implements Descr
      * @since 2.24
      * @return true if the slave agent port is enforced on this instance.
      */
-    @Restricted(DoNotUse.class) // only for index.groovy
+    @Restricted(NoExternalUse.class)
     public boolean isSlaveAgentPortEnforced() {
         return Jenkins.getInstance().isSlaveAgentPortEnforced();
     }
@@ -114,10 +114,12 @@ public class GlobalSecurityConfiguration extends ManagementLink implements Descr
             j.setDisableRememberMe(security.optBoolean("disableRememberMe", false));
             j.setSecurityRealm(SecurityRealm.all().newInstanceFromRadioList(security, "realm"));
             j.setAuthorizationStrategy(AuthorizationStrategy.all().newInstanceFromRadioList(security, "authorization"));
-            try {
-                j.setSlaveAgentPort(new ServerTcpPort(security.getJSONObject("slaveAgentPort")).getPort());
-            } catch (IOException e) {
-                throw new hudson.model.Descriptor.FormException(e, "slaveAgentPortType");
+            if (!isSlaveAgentPortEnforced()) {
+                try {
+                    j.setSlaveAgentPort(new ServerTcpPort(security.getJSONObject("slaveAgentPort")).getPort());
+                } catch (IOException e) {
+                    throw new hudson.model.Descriptor.FormException(e, "slaveAgentPortType");
+                }
             }
             Set<String> agentProtocols = new TreeSet<>();
             if (security.has("agentProtocol")) {

test/src/test/groovy/jenkins/bugs/Jenkins41511Test.java

+package jenkins.bugs;
+
+import org.junit.BeforeClass;
+import org.junit.Rule;
+import org.junit.Test;
+import org.jvnet.hudson.test.JenkinsRule;
+
+import hudson.security.HudsonPrivateSecurityRealm;
+import jenkins.model.Jenkins;
+
+public class Jenkins41511Test {
+
+    @BeforeClass
+    public static void setUpClass() {
+        System.setProperty(Jenkins.class.getName()+".slaveAgentPort", "10000");
+        System.setProperty(Jenkins.class.getName()+".slaveAgentPortEnforce", "true");
+    }
+
+    @Rule
+    public JenkinsRule j = new JenkinsRule();
+
+    @Test
+    public void configRoundTrip() throws Exception {
+        Jenkins.getInstance().setSecurityRealm(new HudsonPrivateSecurityRealm(true, false, null));
+        j.submit(j.createWebClient().goTo("configureSecurity").getFormByName("config"));
+    }
+}