When parsing operation token allow a zero version (#2591)

Author: Quinn-With-Two-Ns

temporal-sdk/src/main/java/io/temporal/internal/nexus/OperationTokenUtil.java

@@ -31,7 +31,7 @@ public static WorkflowRunOperationToken loadWorkflowRunOperationToken(String ope
       throw new IllegalArgumentException(
           "Invalid workflow run token: incorrect operation token type: " + token.getType());
     }
-    if (token.getVersion() != null) {
+    if (token.getVersion() != null && token.getVersion() != 0) {
       throw new IllegalArgumentException("Invalid workflow run token: unexpected version field");
     }
     if (Strings.isNullOrEmpty(token.getWorkflowId())) {

temporal-sdk/src/test/java/io/temporal/internal/nexus/WorkflowRunTokenTest.java

@@ -80,6 +80,20 @@ public void loadWorkflowIdFromOperationToken() {
             encoder.encodeToString(json.getBytes())));
   }
 
+  @Test
+  public void loadWorkflowIdFromGoOperationToken() {
+    // This is a token generated by the Go SDK, use this to test compatibility
+    // across SDKs.
+    String goOperationToken = "eyJ2IjowLCJ0IjoxLCJucyI6Im5zIiwid2lkIjoidyJ9";
+
+    WorkflowRunOperationToken token =
+        OperationTokenUtil.loadWorkflowRunOperationToken(goOperationToken);
+    Assert.assertEquals("w", token.getWorkflowId());
+    Assert.assertEquals("ns", token.getNamespace());
+    Assert.assertEquals(Integer.valueOf(0), token.getVersion());
+    Assert.assertEquals(OperationTokenType.WORKFLOW_RUN, token.getType());
+  }
+
   @Test
   public void loadWorkflowIdFromBadOperationToken() {
     // Bad token, empty json