add check maintenance period and throw error

Author: Sunny Jiao

common/src/main/java/org/tron/core/exception/MaintenanceClearingException.java

@@ -0,0 +1,20 @@
+package org.tron.core.exception;
+
+/**
+ * Maintenance clearing exception - thrown when system is in maintenance clearing state
+ * Please try again later
+ */
+public class MaintenanceClearingException extends TronException {
+
+  public MaintenanceClearingException() {
+    super();
+  }
+
+  public MaintenanceClearingException(String message) {
+    super(message);
+  }
+
+  public MaintenanceClearingException(String message, Throwable cause) {
+    super(message, cause);
+  }
+}

framework/src/main/java/org/tron/core/Wallet.java

@@ -182,6 +182,7 @@
 import org.tron.core.exception.HeaderNotFound;
 import org.tron.core.exception.ItemNotFoundException;
 import org.tron.core.exception.JsonRpcInvalidParamsException;
+import org.tron.core.exception.MaintenanceClearingException;
 import org.tron.core.exception.NonUniqueObjectException;
 import org.tron.core.exception.PermissionException;
 import org.tron.core.exception.SignatureFormatException;
@@ -770,14 +771,23 @@ public WitnessList getWitnessList() {
     return builder.build();
   }
 
-  public WitnessList getPaginatedNowWitnessList(long offset, long limit) {
+  public WitnessList getPaginatedNowWitnessList(long offset, long limit) throws MaintenanceClearingException {
     if (limit <= 0 || offset < 0) {
       return null;
     }
     if (limit > WITNESS_COUNT_LIMIT_MAX) {
       limit = WITNESS_COUNT_LIMIT_MAX;
     }
-
+    
+    /*
+      In the maintenance period, the VoteStores will be cleared.
+      To avoid the race condition of VoteStores deleted but Witness vote counts not updated, return retry error.
+    */
+    if (chainBaseManager.getDynamicPropertiesStore().getStateFlag() == 1) {
+      long maintenanceLogicTime = chainBaseManager.getDynamicPropertiesStore().getMaintenanceSkipSlots() * BLOCK_PRODUCED_INTERVAL / 1000;
+      String message = "Maintenance clearing, please try again later after " + maintenanceLogicTime + " seconds.";
+      throw new MaintenanceClearingException(message);
+    }
     // It contains the final vote count at the end of the last epoch.
     List<WitnessCapsule> witnessCapsuleList = chainBaseManager.getWitnessStore().getAllWitnesses();
     if (offset >= witnessCapsuleList.size()) {

framework/src/main/java/org/tron/core/services/RpcApiService.java

@@ -89,6 +89,7 @@
 import org.tron.core.exception.ContractExeException;
 import org.tron.core.exception.ContractValidateException;
 import org.tron.core.exception.ItemNotFoundException;
+import org.tron.core.exception.MaintenanceClearingException;
 import org.tron.core.exception.NonUniqueObjectException;
 import org.tron.core.exception.StoreException;
 import org.tron.core.exception.VMIllegalException;
@@ -399,8 +400,12 @@ public void listWitnesses(EmptyMessage request, StreamObserver<WitnessList> resp
     @Override
     public void getPaginatedNowWitnessList(PaginatedMessage request,
         StreamObserver<WitnessList> responseObserver) {
-      responseObserver.onNext(
-          wallet.getPaginatedNowWitnessList(request.getOffset(), request.getLimit()));
+      try {
+        responseObserver.onNext(
+            wallet.getPaginatedNowWitnessList(request.getOffset(), request.getLimit()));
+      } catch (MaintenanceClearingException e) {
+        responseObserver.onError(getRunTimeException(e));
+      }
       responseObserver.onCompleted();
     }
 
@@ -1883,8 +1888,12 @@ public void listWitnesses(EmptyMessage request,
     @Override
     public void getPaginatedNowWitnessList(PaginatedMessage request,
         StreamObserver<WitnessList> responseObserver) {
-      responseObserver.onNext(
-          wallet.getPaginatedNowWitnessList(request.getOffset(), request.getLimit()));
+      try {
+        responseObserver.onNext(
+            wallet.getPaginatedNowWitnessList(request.getOffset(), request.getLimit()));
+      } catch (MaintenanceClearingException e) {
+        responseObserver.onError(getRunTimeException(e));
+      }
       responseObserver.onCompleted();
     }
 

framework/src/main/java/org/tron/core/services/http/GetPaginatedNowWitnessListServlet.java

@@ -8,6 +8,7 @@
 import org.springframework.stereotype.Component;
 import org.tron.api.GrpcAPI;
 import org.tron.core.Wallet;
+import org.tron.core.exception.MaintenanceClearingException;
 
 // Get the paged list of witnesses info with realtime vote counts
 @Component
@@ -40,7 +41,7 @@ protected void doPost(HttpServletRequest request, HttpServletResponse response)
   }
 
   private void fillResponse(long offset, long limit, boolean visible, HttpServletResponse response)
-      throws IOException {
+      throws IOException, MaintenanceClearingException {
     GrpcAPI.WitnessList reply = wallet.getPaginatedNowWitnessList(offset, limit);
     if (reply != null) {
       response.getWriter().println(JsonFormat.printToString(reply, visible));

framework/src/test/java/org/tron/core/WalletTest.java

@@ -74,6 +74,7 @@
 import org.tron.core.config.args.Args;
 import org.tron.core.exception.ContractExeException;
 import org.tron.core.exception.ContractValidateException;
+import org.tron.core.exception.MaintenanceClearingException;
 import org.tron.core.exception.NonUniqueObjectException;
 import org.tron.core.store.DynamicPropertiesStore;
 import org.tron.core.utils.ProposalUtil.ProposalType;
@@ -858,30 +859,37 @@ public void testGetDelegatedResourceV2() {
 
   @Test
   public void testGetPaginatedNowWitnessList_CornerCase() {
-    GrpcAPI.WitnessList witnessList = wallet.getPaginatedNowWitnessList(-100, 0);
-    Assert.assertTrue("Should return an empty witness list when offset is negative",
-        witnessList == null);
-
-    witnessList = wallet.getPaginatedNowWitnessList(100, 0);
-    Assert.assertTrue("Should return an empty witness list when limit is 0",
-        witnessList == null);
-
-    String fakeWitnessAddressPrefix = "fake_witness";
-    int fakeNumberOfWitnesses = 1000 + 10;
-    // Mock additional witnesses with vote counts greater than 1000
-    for (int i = 0; i < fakeNumberOfWitnesses; i++) {
-      saveWitnessWith(fakeWitnessAddressPrefix + i, 200);
-    }
+    try {
+      // To avoid throw MaintenanceClearingException
+      dbManager.getChainBaseManager().getDynamicPropertiesStore().saveStateFlag(0);
+
+      GrpcAPI.WitnessList witnessList = wallet.getPaginatedNowWitnessList(-100, 0);
+      Assert.assertTrue("Should return an empty witness list when offset is negative",
+          witnessList == null);
+
+      witnessList = wallet.getPaginatedNowWitnessList(100, 0);
+      Assert.assertTrue("Should return an empty witness list when limit is 0",
+          witnessList == null);
+
+      String fakeWitnessAddressPrefix = "fake_witness";
+      int fakeNumberOfWitnesses = 1000 + 10;
+      // Mock additional witnesses with vote counts greater than 1000
+      for (int i = 0; i < fakeNumberOfWitnesses; i++) {
+        saveWitnessWith(fakeWitnessAddressPrefix + i, 200);
+      }
 
-    witnessList = wallet.getPaginatedNowWitnessList(0, 1000000);
-    // Check the returned witness list should contain 1000 witnesses with descending vote count
-    Assert.assertTrue("Witness list should contain 1000 witnesses",
-        witnessList.getWitnessesCount() == 1000);
+      witnessList = wallet.getPaginatedNowWitnessList(0, 1000000);
+      // Check the returned witness list should contain 1000 witnesses with descending vote count
+      Assert.assertTrue("Witness list should contain 1000 witnesses",
+          witnessList.getWitnessesCount() == 1000);
 
-    // clean up, delete the fake witnesses
-    for (int i = 0; i < fakeNumberOfWitnesses; i++) {
-      chainBaseManager.getWitnessStore()
-          .delete(ByteString.copyFromUtf8(fakeWitnessAddressPrefix + i).toByteArray());
+      // clean up, delete the fake witnesses
+      for (int i = 0; i < fakeNumberOfWitnesses; i++) {
+        chainBaseManager.getWitnessStore()
+            .delete(ByteString.copyFromUtf8(fakeWitnessAddressPrefix + i).toByteArray());
+      }
+    } catch (MaintenanceClearingException e) {
+       Assert.fail(e.getMessage());
     }
   }
 
@@ -914,7 +922,14 @@ public void testGetPaginatedNowWitnessList() {
     chainBaseManager.getVotesStore().put(votesCapsule.createDbKey(), votesCapsule);
 
     logger.info("now request paginated witness list with 0 offset and 10 limit:");
-    GrpcAPI.WitnessList witnessList2 = wallet.getPaginatedNowWitnessList(0, 10);
+    GrpcAPI.WitnessList witnessList2 = null;
+     try {
+      // To avoid throw MaintenanceClearingException
+      dbManager.getChainBaseManager().getDynamicPropertiesStore().saveStateFlag(0);
+      witnessList2 = wallet.getPaginatedNowWitnessList(0, 10);
+    } catch (MaintenanceClearingException e) {
+      Assert.fail(e.getMessage());
+    }
     // Check the returned witness list should contain 10 witnesses with descending vote count
     Assert.assertTrue("Witness list should contain 10 witnesses",
         witnessList2.getWitnessesCount() == 10);