[Fix][Master] Fix Potential danger in the event of a worker failover (#15689)

* clean unused import

* fix style check

* fix when path is null or empty, it will cause serverhost is null,

* fix UT test (#15684)

* [Fix-15639] parameterPassing is null case NPE (#15678)

Co-authored-by: caishunfeng <caishunfeng2021@gmail.com>

* fix  when path is null or empty, it will cause serverhost is null,

dolphinscheduler-master/src/main/java/org/apache/dolphinscheduler/server/master/registry/MasterRegistryClient.java

@@ -131,9 +131,12 @@ public class MasterRegistryClient implements AutoCloseable {
     public void removeWorkerNodePath(String path, RegistryNodeType nodeType, boolean failover) {
         log.info("{} node deleted : {}", nodeType, path);
         try {
-            String serverHost = null;
+            if (StringUtils.isEmpty(path)) {
-            if (!StringUtils.isEmpty(path)) {
+                log.error("server down error: node empty path: {}, nodeType:{}", path, nodeType);
-                serverHost = registryClient.getHostByEventDataPath(path);
+                return;
+            }
+
+            String serverHost = registryClient.getHostByEventDataPath(path);
             if (StringUtils.isEmpty(serverHost)) {
                 log.error("server down error: unknown path: {}", path);
                 return;
@@ -141,7 +144,7 @@ public class MasterRegistryClient implements AutoCloseable {
             if (!registryClient.exists(path)) {
                 log.info("path: {} not exists", path);
             }
-            }
+
             // failover server
             if (failover) {
                 failoverService.failoverServerWhenDown(serverHost, nodeType);

dolphinscheduler-master/src/test/java/org/apache/dolphinscheduler/server/master/registry/MasterRegistryClientTest.java

@@ -103,4 +103,10 @@ public class MasterRegistryClientTest {
         // Cannot mock static methods
         masterRegistryClient.removeWorkerNodePath("/path", RegistryNodeType.WORKER, true);
     }
+
+    @Test
+    public void removeWorkNodePathTest() {
+        masterRegistryClient.removeWorkerNodePath("", RegistryNodeType.WORKER, true);
+        masterRegistryClient.removeWorkerNodePath(null, RegistryNodeType.WORKER, true);
+    }
 }