Fix null pointer on trigger immediately (#1865)

Author: Quinn-With-Two-Ns

temporal-sdk/src/main/java/io/temporal/client/schedules/Schedule.java

@@ -73,9 +73,9 @@ public Builder setSpec(ScheduleSpec spec) {
     }
 
     /**
-     * Set the spec for this schedule
+     * Set the policy for this schedule
      *
-     * @see ScheduleSpec
+     * @see SchedulePolicy
      */
     public Builder setPolicy(SchedulePolicy policy) {
       this.policy = policy;

temporal-sdk/src/main/java/io/temporal/internal/client/RootScheduleClientInvoker.java

@@ -98,10 +98,11 @@ public void createSchedule(CreateScheduleInput input) {
       }
 
       if (input.getOptions().isTriggerImmediately()) {
-        patchBuilder.setTriggerImmediately(
-            TriggerImmediatelyRequest.newBuilder()
-                .setOverlapPolicy(input.getSchedule().getPolicy().getOverlap())
-                .build());
+        TriggerImmediatelyRequest.Builder triggerRequest = TriggerImmediatelyRequest.newBuilder();
+        if (input.getSchedule().getPolicy() != null) {
+          triggerRequest.setOverlapPolicy(input.getSchedule().getPolicy().getOverlap());
+        }
+        patchBuilder.setTriggerImmediately(triggerRequest.build());
       }
 
       request.setInitialPatch(patchBuilder.build());

temporal-sdk/src/test/java/io/temporal/client/schedules/ScheduleTest.java

@@ -235,6 +235,20 @@ public void triggerSchedule() {
     }
   }
 
+  @Test
+  public void triggerScheduleNoPolicy() {
+    ScheduleClient client = createScheduleClient();
+    // Create schedule
+    ScheduleOptions options = ScheduleOptions.newBuilder().setTriggerImmediately(true).build();
+    String scheduleId = UUID.randomUUID().toString();
+    Schedule schedule =
+        createTestSchedule().setState(ScheduleState.newBuilder().setPaused(true).build()).build();
+    ScheduleHandle handle = client.createSchedule(scheduleId, schedule, options);
+    waitForActions(handle, 1);
+    // Cleanup schedule
+    handle.delete();
+  }
+
   @Test
   public void backfillSchedules() {
     // assumeTrue("skipping for test server", SDKTestWorkflowRule.useExternalService);