`JedisConnection.close()` fails to release connection to pool if subscription cleanup fails

[yu-shiba]

Hi,
After upgrading to 2.7.1, the application associated with RedisMessageListenerContainer became unresponsive.
The problem was caused by a misconfiguration in our environment where Istio disconnects the connection after 1 hour. When investigating this, we discovered that Jedis leaks when an exception occurs during JedisConnection close.

spring-data-redis/src/main/java/org/springframework/data/redis/connection/jedis/JedisConnection.java

Line 336 in 0d0df32

subscription.close();

The following is a stack trace of the problem.
The first exception is a disconnection and JedisConnection#close() is executed, but the second exception occurs at subscription.close() and jedis.close() is not executed.

spring-data-redis/src/main/java/org/springframework/data/redis/connection/jedis/JedisConnection.java

Line 342 in 0d0df32

jedis.close();

1st exception

org.springframework.data.redis.RedisConnectionFailureException: Unexpected end of stream.; nested exception is redis.clients.jedis.exceptions.JedisConnectionException: Unexpected end of stream.
	at org.springframework.data.redis.connection.jedis.JedisExceptionConverter.convert(JedisExceptionConverter.java:65)
	at org.springframework.data.redis.connection.jedis.JedisExceptionConverter.convert(JedisExceptionConverter.java:42)
	at org.springframework.data.redis.PassThroughExceptionTranslationStrategy.translate(PassThroughExceptionTranslationStrategy.java:44)
	at org.springframework.data.redis.FallbackExceptionTranslationStrategy.translate(FallbackExceptionTranslationStrategy.java:42)
	at org.springframework.data.redis.connection.jedis.JedisConnection.convertJedisAccessException(JedisConnection.java:187)
	at org.springframework.data.redis.connection.jedis.JedisConnection.doWithJedis(JedisConnection.java:820)
	at org.springframework.data.redis.connection.jedis.JedisConnection.pSubscribe(JedisConnection.java:725)
	at org.springframework.data.redis.listener.RedisMessageListenerContainer$Subscriber.doSubscribe(RedisMessageListenerContainer.java:1231)
	at org.springframework.data.redis.listener.RedisMessageListenerContainer$BlockingSubscriber.lambda$eventuallyPerformSubscription$2(RedisMessageListenerContainer.java:1433)
	at java.base/java.lang.Thread.run(Unknown Source)
Caused by: redis.clients.jedis.exceptions.JedisConnectionException: Unexpected end of stream.
	at redis.clients.jedis.util.RedisInputStream.ensureFill(RedisInputStream.java:202)
	at redis.clients.jedis.util.RedisInputStream.readByte(RedisInputStream.java:43)
	at redis.clients.jedis.Protocol.process(Protocol.java:165)
	at redis.clients.jedis.Protocol.read(Protocol.java:230)
	at redis.clients.jedis.Connection.readProtocolWithCheckingBroken(Connection.java:352)
	at redis.clients.jedis.Connection.getUnflushedObjectMultiBulkReply(Connection.java:314)
	at redis.clients.jedis.BinaryJedisPubSub.process(BinaryJedisPubSub.java:101)
	at redis.clients.jedis.BinaryJedisPubSub.proceedWithPatterns(BinaryJedisPubSub.java:89)
	at redis.clients.jedis.BinaryJedis.psubscribe(BinaryJedis.java:3900)
	at org.springframework.data.redis.connection.jedis.JedisConnection.lambda$pSubscribe$7(JedisConnection.java:730)
	at org.springframework.data.redis.connection.jedis.JedisConnection.doWithJedis(JedisConnection.java:818)
	... 4 common frames omitted

2nd exception

redis.clients.jedis.exceptions.JedisConnectionException: java.net.SocketException: Broken pipe
	at redis.clients.jedis.Connection.flush(Connection.java:342)
	at redis.clients.jedis.BinaryJedisPubSub.punsubscribe(BinaryJedisPubSub.java:63)
	at org.springframework.data.redis.connection.jedis.JedisSubscription.doClose(JedisSubscription.java:49)
	at org.springframework.data.redis.connection.util.AbstractSubscription.close(AbstractSubscription.java:106)
	at org.springframework.data.redis.connection.jedis.JedisConnection.close(JedisConnection.java:336)
	at org.springframework.data.redis.listener.RedisMessageListenerContainer$Subscriber.closeConnection(RedisMessageListenerContainer.java:1323)
	at org.springframework.data.redis.listener.RedisMessageListenerContainer.handleSubscriptionException(RedisMessageListenerContainer.java:893)
	at org.springframework.data.redis.listener.RedisMessageListenerContainer$BlockingSubscriber.lambda$eventuallyPerformSubscription$2(RedisMessageListenerContainer.java:1437)
	at java.base/java.lang.Thread.run(Unknown Source)
Caused by: java.net.SocketException: Broken pipe
	at java.base/sun.nio.ch.NioSocketImpl.implWrite(Unknown Source)
	at java.base/sun.nio.ch.NioSocketImpl.write(Unknown Source)
	at java.base/sun.nio.ch.NioSocketImpl$2.write(Unknown Source)
	at java.base/java.net.Socket$SocketOutputStream.write(Unknown Source)
	at redis.clients.jedis.util.RedisOutputStream.flushBuffer(RedisOutputStream.java:52)
	at redis.clients.jedis.util.RedisOutputStream.flush(RedisOutputStream.java:133)
	at redis.clients.jedis.Connection.flush(Connection.java:339)
	... 8 common frames omitted

[mp911de]

The cause why the application locks up is that the subscription release fails and the code to release the connection back to the pool is never invoked. We need to fix that.