fix gRPC query mappers (#736)

Author: mkolodezny

src/main/java/com/uber/cadence/internal/compatibility/proto/RequestMapper.java

@@ -118,10 +118,12 @@ public static CountWorkflowExecutionsRequest countWorkflowExecutionsRequest(
     if (t == null) {
       return null;
     }
-    return CountWorkflowExecutionsRequest.newBuilder()
-        .setDomain(t.getDomain())
-        .setQuery(t.getQuery())
-        .build();
+    CountWorkflowExecutionsRequest.Builder request =
+        CountWorkflowExecutionsRequest.newBuilder().setDomain(t.getDomain());
+    if (t.getQuery() != null) {
+      request.setQuery(t.getQuery());
+    }
+    return request.build();
   }
 
   public static DescribeTaskListRequest describeTaskListRequest(
@@ -145,11 +147,13 @@ public static ListArchivedWorkflowExecutionsRequest listArchivedWorkflowExecutio
     ListArchivedWorkflowExecutionsRequest.Builder request =
         ListArchivedWorkflowExecutionsRequest.newBuilder()
             .setDomain(t.getDomain())
-            .setPageSize(t.getPageSize())
-            .setQuery(t.getQuery());
+            .setPageSize(t.getPageSize());
     if (t.getNextPageToken() != null) {
       request.setNextPageToken(arrayToByteString(t.getNextPageToken()));
     }
+    if (t.getQuery() != null) {
+      request.setQuery(t.getQuery());
+    }
     return request.build();
   }
 
@@ -373,11 +377,13 @@ public static ScanWorkflowExecutionsRequest scanWorkflowExecutionsRequest(
     ScanWorkflowExecutionsRequest.Builder request =
         ScanWorkflowExecutionsRequest.newBuilder()
             .setDomain(t.getDomain())
-            .setPageSize(t.getPageSize())
-            .setQuery(t.getQuery());
+            .setPageSize(t.getPageSize());
     if (t.getNextPageToken() != null) {
       request.setNextPageToken(arrayToByteString(t.getNextPageToken()));
     }
+    if (t.getQuery() != null) {
+      request.setQuery(t.getQuery());
+    }
     return request.build();
   }
 
@@ -584,11 +590,13 @@ public static ListWorkflowExecutionsRequest listWorkflowExecutionsRequest(
     ListWorkflowExecutionsRequest.Builder request =
         ListWorkflowExecutionsRequest.newBuilder()
             .setDomain(t.getDomain())
-            .setPageSize(t.getPageSize())
-            .setQuery(t.getQuery());
+            .setPageSize(t.getPageSize());
     if (t.getNextPageToken() != null) {
       request.setNextPageToken(arrayToByteString(t.getNextPageToken()));
     }
+    if (t.getQuery() != null) {
+      request.setQuery(t.getQuery());
+    }
     return request.build();
   }
 

src/main/java/com/uber/cadence/internal/compatibility/proto/TypeMapper.java

@@ -189,7 +189,7 @@ static ClusterReplicationConfiguration clusterReplicationConfiguration(
 
   static WorkflowQuery workflowQuery(com.uber.cadence.WorkflowQuery t) {
     if (t == null) {
-      return WorkflowQuery.newBuilder().build();
+      return null;
     }
     return WorkflowQuery.newBuilder()
         .setQueryType(t.getQueryType())