fix: incorrect min offset returned from TieredMessageStore when local store returns -1

Author: Kris20030907

tieredstore/src/main/java/org/apache/rocketmq/tieredstore/TieredMessageStore.java

@@ -310,6 +310,9 @@ public long getMinOffsetInQueue(String topic, int queueId) {
         if (minOffsetInTieredStore < 0) {
             return minOffsetInNextStore;
         }
+        if (minOffsetInNextStore < 0) {
+            return minOffsetInTieredStore;
+        }
         return Math.min(minOffsetInNextStore, minOffsetInTieredStore);
     }
 

tieredstore/src/test/java/org/apache/rocketmq/tieredstore/TieredMessageStoreTest.java

@@ -238,7 +238,21 @@ public void testGetMinOffsetInQueue() {
         Mockito.when(defaultStore.getMinOffsetInQueue(anyString(), anyInt())).thenReturn(100L);
         Assert.assertEquals(100L, currentStore.getMinOffsetInQueue(mq.getTopic(), mq.getQueueId()));
 
-        Mockito.when(flatFile.getConsumeQueueMinOffset()).thenReturn(10L);
+        Assert.assertEquals(flatFile.getConsumeQueueMinOffset(),
+            currentStore.getMinOffsetInQueue(mq.getTopic(), mq.getQueueId()));
+
+        FlatFileStore mockFlatFileStore = Mockito.mock(FlatFileStore.class);
+        FlatMessageFile mockFlatFile = Mockito.mock(FlatMessageFile.class);
+        Mockito.when(mockFlatFileStore.getFlatFile(any(MessageQueue.class))).thenReturn(mockFlatFile);
+        Mockito.when(mockFlatFile.getConsumeQueueMinOffset()).thenReturn(10L);
+        Mockito.when(defaultStore.getMinOffsetInQueue(anyString(), anyInt())).thenReturn(-1L);
+        try {
+            Field field = currentStore.getClass().getDeclaredField("flatFileStore");
+            field.setAccessible(true);
+            field.set(currentStore, mockFlatFileStore);
+        } catch (NoSuchFieldException | IllegalAccessException e) {
+            Assert.fail(e.getClass().getCanonicalName() + ": " + e.getMessage());
+        }
         Assert.assertEquals(10L, currentStore.getMinOffsetInQueue(mq.getTopic(), mq.getQueueId()));
     }