fix: return false outside workflow code,

Author: patbeqo

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

@@ -962,7 +962,8 @@ static void assertNotReadOnly(String action) {
   }
 
   public static boolean isSubjectToReplay() {
-    return getRootWorkflowContext().isSubjectToReplay();
+    Optional<WorkflowThread> thread = DeterministicRunnerImpl.currentThreadInternalIfPresent();
+    return thread.isPresent() && getRootWorkflowContext().isSubjectToReplay();
   }
 
   static void assertNotInUpdateHandler(String message) {

temporal-sdk/src/main/java/io/temporal/workflow/unsafe/WorkflowUnsafe.java

@@ -56,9 +56,8 @@ public static boolean isReplaying() {
    * functions run once against the current state and are never re-executed, so they are not subject
    * to replay even while {@link #isReplaying()} reports true.
    *
-   * <p>Must be called from Workflow code.
-   *
-   * @return true if the calling context is re-executed on replay
+   * @return true if the calling context is re-executed on replay. This method always returns false
+   *     if called from a non workflow thread.
    */
   @Experimental
   public static boolean isSubjectToReplay() {

temporal-sdk/src/test/java/io/temporal/workflow/WorkflowUnsafeSubjectToReplayTest.java

@@ -1,6 +1,7 @@
 package io.temporal.workflow;
 
 import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertFalse;
 
 import io.temporal.client.WorkflowClient;
 import io.temporal.client.WorkflowStub;
@@ -79,6 +80,11 @@ public void isSubjectToReplay() {
     assertEquals(expected, calls);
   }
 
+  @Test
+  public void isSubjectToReplayOffWorkflowThread() {
+    assertFalse(WorkflowUnsafe.isSubjectToReplay());
+  }
+
   private static void record(String name) {
     calls.put(name, WorkflowUnsafe.isSubjectToReplay());
   }