Fix memory leak of command inputs (#2262)

Fix memory leak of command inputs

Author: Quinn-With-Two-Ns

temporal-sdk/src/main/java/io/temporal/internal/statemachines/ActivityStateMachine.java

@@ -275,6 +275,7 @@ public void createScheduleActivityTaskCommand() {
             .setCommandType(CommandType.COMMAND_TYPE_SCHEDULE_ACTIVITY_TASK)
             .setScheduleActivityTaskCommandAttributes(parameters.getAttributes())
             .build());
+    parameters = null; // avoiding retaining large input for the duration of the activity
   }
 
   private void setStartedCommandEventId() {
@@ -455,7 +456,6 @@ private void createRequestCancelActivityTaskCommand() {
                 RequestCancelActivityTaskCommandAttributes.newBuilder()
                     .setScheduledEventId(getInitialCommandEventId()))
             .build());
-    parameters = null; // avoid retaining large input for the duration of the activity
   }
 
   public static class FailureResult {

temporal-sdk/src/main/java/io/temporal/internal/statemachines/EntityStateMachineInitialCommand.java

@@ -20,16 +20,17 @@
 
 package io.temporal.internal.statemachines;
 
+import static io.temporal.internal.common.WorkflowExecutionUtils.isCommandEvent;
+
 import io.temporal.api.command.v1.Command;
 import io.temporal.api.enums.v1.CommandType;
+import io.temporal.api.history.v1.HistoryEvent;
 import io.temporal.workflow.Functions;
 import javax.annotation.Nullable;
 
 class EntityStateMachineInitialCommand<State, ExplicitEvent, Data>
     extends EntityStateMachineBase<State, ExplicitEvent, Data> {
-
   private CancellableCommand command;
-
   private long initialCommandEventId;
 
   public EntityStateMachineInitialCommand(
@@ -56,7 +57,17 @@ protected final void addCommand(Command command) {
   }
 
   protected final void cancelCommand() {
-    command.cancel();
+    if (command != null) {
+      command.cancel();
+    }
+  }
+
+  public WorkflowStateMachines.HandleEventStatus handleEvent(
+      HistoryEvent event, boolean hasNextEvent) {
+    if (isCommandEvent(event)) {
+      command = null;
+    }
+    return super.handleEvent(event, hasNextEvent);
   }
 
   protected long getInitialCommandEventId() {

temporal-sdk/src/main/java/io/temporal/internal/sync/SyncWorkflowContext.java

@@ -278,16 +278,20 @@ public <T> ActivityOutput<T> executeActivity(ActivityInput<T> input) {
     ActivityOutput<Optional<Payloads>> output =
         executeActivityOnce(input.getActivityName(), input.getOptions(), input.getHeader(), args);
 
+    // Avoid passing the input to the output handle as it causes the input to be retained for the
+    // duration of the operation.
+    Type resultType = input.getResultType();
+    Class<T> resultClass = input.getResultClass();
     return new ActivityOutput<>(
         output.getActivityId(),
         output
             .getResult()
             .handle(
                 (r, f) -> {
                   if (f == null) {
-                    return input.getResultType() != Void.TYPE
+                    return resultType != Void.TYPE
                         ? dataConverterWithActivityContext.fromPayloads(
-                            0, r, input.getResultClass(), input.getResultType())
+                            0, r, resultClass, resultType)
                         : null;
                   } else {
                     throw dataConverterWithActivityContext.failureToException(
@@ -412,13 +416,16 @@ public <R> LocalActivityOutput<R> executeLocalActivity(LocalActivityInput<R> inp
         null,
         serializedResult);
 
+    // Avoid passing the input to the output handle as it causes the input to be retained for the
+    // duration of the operation.
+    Type resultType = input.getResultType();
+    Class<R> resultClass = input.getResultClass();
     Promise<R> result =
         serializedResult.handle(
             (r, f) -> {
               if (f == null) {
-                return input.getResultClass() != Void.TYPE
-                    ? dataConverterWithActivityContext.fromPayloads(
-                        0, r, input.getResultClass(), input.getResultType())
+                return resultClass != Void.TYPE
+                    ? dataConverterWithActivityContext.fromPayloads(0, r, resultClass, resultType)
                     : null;
               } else {
                 throw dataConverterWithActivityContext.failureToException(
@@ -708,11 +715,14 @@ public <R> ChildWorkflowOutput<R> executeChildWorkflow(ChildWorkflowInput<R> inp
               return null;
             });
 
+    // Avoid passing the input to the output handle as it causes the input to be retained for the
+    // duration of the operation.
+    Type resultType = input.getResultType();
+    Class<R> resultClass = input.getResultClass();
     Promise<R> result =
         resultPromise.thenApply(
             (b) ->
-                dataConverterWithChildWorkflowContext.fromPayloads(
-                    0, b, input.getResultClass(), input.getResultType()));
+                dataConverterWithChildWorkflowContext.fromPayloads(0, b, resultClass, resultType));
     return new ChildWorkflowOutput<>(result, executionPromise);
   }