Closes #2940 Sharded PubSub subscriptions not recovered after disconnection and re-connection. (#3026)

Backport to 6.4.x branch

Author: ggivo

src/main/java/io/lettuce/core/pubsub/PubSubEndpoint.java

@@ -129,6 +129,14 @@ public Set<K> getChannels() {
         return unwrap(this.channels);
     }
 
+    public boolean hasShardChannelSubscriptions() {
+        return !shardChannels.isEmpty();
+    }
+
+    public Set<K> getShardChannels() {
+        return unwrap(this.shardChannels);
+    }
+
     public boolean hasPatternSubscriptions() {
         return !patterns.isEmpty();
     }

src/main/java/io/lettuce/core/pubsub/StatefulRedisPubSubConnectionImpl.java

@@ -130,6 +130,10 @@ protected List<RedisFuture<Void>> resubscribe() {
             result.add(async().subscribe(toArray(endpoint.getChannels())));
         }
 
+        if (endpoint.hasShardChannelSubscriptions()) {
+            result.add(async().ssubscribe(toArray(endpoint.getShardChannels())));
+        }
+
         if (endpoint.hasPatternSubscriptions()) {
             result.add(async().psubscribe(toArray(endpoint.getPatterns())));
         }

src/test/java/io/lettuce/core/pubsub/PubSubCommandTest.java

@@ -84,6 +84,8 @@ class PubSubCommandTest extends AbstractRedisClientTest {
 
     BlockingQueue<Long> counts = listener.getCounts();
 
+    BlockingQueue<Long> shardCounts = listener.getShardCounts();
+
     String channel = "channel0";
 
     String shardChannel = "shard-channel";
@@ -521,6 +523,24 @@ void resubscribePatternsOnReconnect() throws Exception {
         assertThat(messages.take()).isEqualTo(message);
     }
 
+    @Test
+    void resubscribeShardChannelsOnReconnect() throws Exception {
+        pubsub.ssubscribe(shardChannel);
+        assertThat(shardChannels.take()).isEqualTo(shardChannel);
+        assertThat((long) shardCounts.take()).isEqualTo(1);
+
+        pubsub.quit();
+
+        assertThat(shardChannels.take()).isEqualTo(shardChannel);
+        assertThat((long) shardCounts.take()).isEqualTo(1);
+
+        Wait.untilTrue(pubsub::isOpen).waitOrTimeout();
+
+        redis.spublish(shardChannel, shardMessage);
+        assertThat(shardChannels.take()).isEqualTo(shardChannel);
+        assertThat(messages.take()).isEqualTo(shardMessage);
+    }
+
     @Test
     void adapter() throws Exception {
         final BlockingQueue<Long> localCounts = LettuceFactories.newBlockingQueue();

src/test/java/io/lettuce/core/pubsub/StatefulRedisPubSubConnectionImplUnitTests.java

@@ -10,7 +10,7 @@
 import org.junit.jupiter.api.BeforeEach;
 import org.junit.jupiter.api.Test;
 
-import static org.junit.Assert.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertEquals;
 import static org.junit.jupiter.api.Assertions.assertInstanceOf;
 import static org.mockito.Mockito.*;
 
@@ -78,6 +78,7 @@ void resubscribeChannelSubscription() {
         when(mockedEndpoint.hasChannelSubscriptions()).thenReturn(true);
         when(mockedEndpoint.getChannels()).thenReturn(new HashSet<>(Arrays.asList(new String[] { "channel1", "channel2" })));
         when(mockedEndpoint.hasPatternSubscriptions()).thenReturn(false);
+        when(mockedEndpoint.hasShardChannelSubscriptions()).thenReturn(false);
 
         List<RedisFuture<Void>> subscriptions = connection.resubscribe();
         RedisFuture<Void> commandFuture = subscriptions.get(0);
@@ -87,17 +88,35 @@ void resubscribeChannelSubscription() {
     }
 
     @Test
-    void resubscribeChannelAndPatternSubscription() {
+    void resubscribeShardChannelSubscription() {
+        when(mockedEndpoint.hasShardChannelSubscriptions()).thenReturn(true);
+        when(mockedEndpoint.getShardChannels())
+                .thenReturn(new HashSet<>(Arrays.asList(new String[] { "shard_channel1", "shard_channel2" })));
+        when(mockedEndpoint.hasChannelSubscriptions()).thenReturn(false);
+        when(mockedEndpoint.hasPatternSubscriptions()).thenReturn(false);
+
+        List<RedisFuture<Void>> subscriptions = connection.resubscribe();
+        RedisFuture<Void> commandFuture = subscriptions.get(0);
+
+        assertEquals(1, subscriptions.size());
+        assertInstanceOf(AsyncCommand.class, commandFuture);
+    }
+
+    @Test
+    void resubscribeChannelAndPatternAndShardChanelSubscription() {
         when(mockedEndpoint.hasChannelSubscriptions()).thenReturn(true);
-        when(mockedEndpoint.getChannels()).thenReturn(new HashSet<>(Arrays.asList(new String[] { "channel1", "channel2" })));
         when(mockedEndpoint.hasPatternSubscriptions()).thenReturn(true);
+        when(mockedEndpoint.hasShardChannelSubscriptions()).thenReturn(true);
+        when(mockedEndpoint.getChannels()).thenReturn(new HashSet<>(Arrays.asList(new String[] { "channel1", "channel2" })));
         when(mockedEndpoint.getPatterns()).thenReturn(new HashSet<>(Arrays.asList(new String[] { "bcast*", "echo" })));
-
+        when(mockedEndpoint.getShardChannels())
+                .thenReturn(new HashSet<>(Arrays.asList(new String[] { "shard_channel1", "shard_channel2" })));
         List<RedisFuture<Void>> subscriptions = connection.resubscribe();
 
-        assertEquals(2, subscriptions.size());
+        assertEquals(3, subscriptions.size());
         assertInstanceOf(AsyncCommand.class, subscriptions.get(0));
         assertInstanceOf(AsyncCommand.class, subscriptions.get(1));
+        assertInstanceOf(AsyncCommand.class, subscriptions.get(1));
     }
 
 }