Fix: aborted transaction (due to watch failure) return value from null string to null array. (#692)

* Fix: aborted transaction (due to watch failure) return value from null string to null array.

Also ensure watch works when object store is disabled.

* fix test

* fix another test

* update version

Author: badrishc

.azure/pipelines/azure-pipelines-external-release.yml

@@ -3,7 +3,7 @@
 #      1) update the name: string below (line 6)     -- this is the version for the nuget package (e.g. 1.0.0)
 #      2) update \libs\host\GarnetServer.cs readonly string version  (~line 53)   -- NOTE - these two values need to be the same 
 ###################################### 
-name: 1.0.27
+name: 1.0.28
 trigger:
   branches:
     include:

libs/host/GarnetServer.cs

@@ -52,7 +52,7 @@ public class GarnetServer : IDisposable
         protected StoreWrapper storeWrapper;
 
         // IMPORTANT: Keep the version in sync with .azure\pipelines\azure-pipelines-external-release.yml line ~6.
-        readonly string version = "1.0.27";
+        readonly string version = "1.0.28";
 
         /// <summary>
         /// Resp protocol version

libs/server/Transaction/TransactionManager.cs

@@ -247,6 +247,10 @@ internal void Commit(bool internal_txn = false)
 
         internal void Watch(ArgSlice key, StoreType type)
         {
+            // Update watch type if object store is disabled
+            if (type == StoreType.All && objectStoreBasicContext.IsNull)
+                type = StoreType.Main;
+
             UpdateTransactionStoreType(type);
             watchContainer.AddWatch(key, type);
 

libs/server/Transaction/TxnRespCommands.cs

@@ -79,7 +79,7 @@ private bool NetworkEXEC()
                 else
                 {
                     endReadHead = _origReadHead;
-                    while (!RespWriteUtils.WriteNull(ref dcurr, dend))
+                    while (!RespWriteUtils.WriteNullArray(ref dcurr, dend))
                         SendAndReset();
                 }
 

test/Garnet.test/RespHashTests.cs

@@ -1074,7 +1074,7 @@ public async Task CanFailWhenUseMultiWatchTest()
             await Task.Run(() => UpdateHashMap(key));
 
             res = lightClientRequest.SendCommand("EXEC");
-            expectedResponse = "$-1";
+            expectedResponse = "*-1";
             ClassicAssert.AreEqual(res.AsSpan().Slice(0, expectedResponse.Length).ToArray(), expectedResponse);
 
             // This sequence should work

test/Garnet.test/RespSortedSetTests.cs

@@ -2273,7 +2273,7 @@ public async Task CanFailWhenUseMultiWatchTest()
             await Task.Run(() => UpdateSortedSetKey(key));
 
             res = lightClientRequest.SendCommand("EXEC");
-            expectedResponse = "$-1";
+            expectedResponse = "*-1";
             ClassicAssert.AreEqual(res.AsSpan().Slice(0, expectedResponse.Length).ToArray(), expectedResponse);
 
             // This sequence should work

test/Garnet.test/TransactionTests.cs

@@ -202,7 +202,7 @@ public async Task SimpleWatchTest()
             await Task.Run(() => updateKey("key1", "value1_updated"));
 
             res = lightClientRequest.SendCommand("EXEC");
-            expectedResponse = "$-1";
+            expectedResponse = "*-1";
             ClassicAssert.AreEqual(res.AsSpan().Slice(0, expectedResponse.Length).ToArray(), expectedResponse);
 
             // This one should Commit
@@ -243,7 +243,7 @@ public async Task WatchNonExistentKey()
             await Task.Run(() => updateKey("key1", "value1"));
 
             res = lightClientRequest.SendCommand("EXEC");
-            expectedResponse = "$-1";
+            expectedResponse = "*-1";
             ClassicAssert.AreEqual(res.AsSpan().Slice(0, expectedResponse.Length).ToArray(), expectedResponse);
 
             // This one should Commit
@@ -289,7 +289,7 @@ public async Task WatchKeyFromDisk()
             await Task.Run(() => updateKey("key1", "value1_updated"));
 
             res = lightClientRequest.SendCommand("EXEC");
-            expectedResponse = "$-1";
+            expectedResponse = "*-1";
             ClassicAssert.AreEqual(res.AsSpan().Slice(0, expectedResponse.Length).ToArray(), expectedResponse);
 
             // This one should Commit