[cherry-pick-2.0.1][Bug-7319][MasterServer] fix NPE when switch else branch is empty (#7314)

* fix taskNode NPE

* fix switch node NPE when no else branch
Co-authored-by: Ncaishunfeng <534328519@qq.com>

dolphinscheduler-dao/src/main/java/org/apache/dolphinscheduler/dao/utils/DagHelper.java

@@ -50,7 +50,6 @@ public class DagHelper {
 
     private static final Logger logger = LoggerFactory.getLogger(DagHelper.class);
 
-
     /**
      * generate flow node relation list by task node list;
      * Edges that are not in the task Node List will not be added to the result
@@ -110,7 +109,7 @@ public class DagHelper {
                 List<TaskNode> childNodeList = new ArrayList<>();
                 if (startNode == null) {
                     logger.error("start node name [{}] is not in task node list [{}] ",
-                        startNodeCode,
+                            startNodeCode,
                             taskNodeList
                     );
                     continue;
@@ -135,7 +134,6 @@ public class DagHelper {
         return destTaskNodeList;
     }
 
-
     /**
      * find all the nodes that depended on the start node
      *
@@ -160,7 +158,6 @@ public class DagHelper {
         return resultList;
     }
 
-
     /**
      * find all nodes that start nodes depend on.
      *
@@ -310,6 +307,10 @@ public class DagHelper {
         }
         for (String subsequent : startVertexes) {
             TaskNode taskNode = dag.getNode(subsequent);
+            if (taskNode == null) {
+                logger.error("taskNode {} is null, please check dag", subsequent);
+                continue;
+            }
             if (isTaskNodeNeedSkip(taskNode, skipTaskNodeList)) {
                 setTaskNodeSkip(subsequent, dag, completeTaskList, skipTaskNodeList);
                 continue;
@@ -343,7 +344,6 @@ public class DagHelper {
         return true;
     }
 
-
     /**
      * parse condition task find the branch process
      * set skip flag for another one.
@@ -382,9 +382,6 @@ public class DagHelper {
     /**
      * parse condition task find the branch process
      * set skip flag for another one.
-     *
-     * @param nodeCode
-     * @return
      */
     public static List<String> parseSwitchTask(String nodeCode,
                                                Map<String, TaskNode> skipTaskNodeList,
@@ -443,7 +440,6 @@ public class DagHelper {
         }
     }
 
-
     /***
      * build dag graph
      * @param processDag processDag

dolphinscheduler-server/src/main/java/org/apache/dolphinscheduler/server/master/runner/task/SwitchTaskProcessor.java

@@ -33,6 +33,7 @@ import org.apache.dolphinscheduler.server.utils.LogUtils;
 import org.apache.dolphinscheduler.server.utils.SwitchTaskUtils;
 import org.apache.dolphinscheduler.service.bean.SpringApplicationContext;
 
+import org.apache.commons.collections4.CollectionUtils;
 import org.apache.commons.lang.StringUtils;
 
 import java.util.Date;
@@ -171,7 +172,13 @@ public class SwitchTaskProcessor extends BaseTaskProcessor {
         switchParameters.setResultConditionLocation(finalConditionLocation);
         taskInstance.setSwitchDependency(switchParameters);
 
-        logger.info("the switch task depend result : {}", conditionResult);
+        if (!isValidSwitchResult(switchResultVos.get(finalConditionLocation))) {
+            conditionResult = DependResult.FAILED;
+            logger.error("the switch task depend result is invalid, result:{}, switch branch:{}", conditionResult, finalConditionLocation);
+            return true;
+        }
+
+        logger.info("the switch task depend result:{}, switch branch:{}", conditionResult, finalConditionLocation);
         return true;
     }
 
@@ -216,4 +223,19 @@ public class SwitchTaskProcessor extends BaseTaskProcessor {
         return content;
     }
 
+    /**
+     * check whether switch result is valid
+     */
+    private boolean isValidSwitchResult(SwitchResultVo switchResult) {
+        if (CollectionUtils.isEmpty(switchResult.getNextNode())) {
+            return false;
+        }
+        for (String nextNode : switchResult.getNextNode()) {
+            if (StringUtils.isEmpty(nextNode)) {
+                return false;
+            }
+        }
+        return true;
+    }
+
 }