[FIXED JENKINS-44010] It is possible for Jenkins.crumbIssuer to be unset while...

[FIXED JENKINS-44010] It is possible for Jenkins.crumbIssuer to be unset while the setup wizard is running.

core/src/main/java/jenkins/install/SetupWizard.java

@@ -254,7 +254,10 @@ public class SetupWizard extends PageDecorator {
                 a = securityRealm.getSecurityComponents().manager.authenticate(a);
                 SecurityContextHolder.getContext().setAuthentication(a);
                 CrumbIssuer crumbIssuer = Jenkins.getInstance().getCrumbIssuer();
-                JSONObject data = new JSONObject().accumulate("crumbRequestField", crumbIssuer.getCrumbRequestField()).accumulate("crumb", crumbIssuer.getCrumb(req));
+                JSONObject data = new JSONObject();
+                if (crumbIssuer != null) {
+                    data.accumulate("crumbRequestField", crumbIssuer.getCrumbRequestField()).accumulate("crumb", crumbIssuer.getCrumb(req));
+                }
                 return HttpResponses.okJSON(data);
             } else {
                 return HttpResponses.okJSON();

core/src/main/java/jenkins/model/Jenkins.java

@@ -3673,6 +3673,7 @@ public class Jenkins extends AbstractCIBase implements DirectlyModifiableTopLeve
      *
      * @return null if none is in use.
      */
+    @CheckForNull
     public CrumbIssuer getCrumbIssuer() {
         return crumbIssuer;
     }