Static command interface methods are erroneously verified against command names

[henry701]

Bug Report

Current Behavior

When using RedisCommandFactory with an interface containing static methods, the factory tries to bind them to commands and ends up throwing a CommandMethodSyntaxException, despite the method already having an implementation (since it's static):

io.lettuce.core.dynamic.CommandMethodSyntaxException: Command CONVERT does not exist Offending method: public static java.util.Map<byte[], java.lang.Double> REDACTED.commons.database.redis.commands.interfaces.LettuceRedisStringByteArrayCommands.convertValueScoreListToMap(java.util.List<byte[]>)
    at io.lettuce.core.dynamic.DefaultCommandMethodVerifier.syntaxException(DefaultCommandMethodVerifier.java:167)
    at io.lettuce.core.dynamic.DefaultCommandMethodVerifier.lambda$validate$0(DefaultCommandMethodVerifier.java:71)
    at java.util.Optional.orElseThrow(Optional.java:290)
    at io.lettuce.core.dynamic.DefaultCommandMethodVerifier.validate(DefaultCommandMethodVerifier.java:71)
    at io.lettuce.core.dynamic.ExecutableCommandLookupStrategySupport$DefaultCommandFactoryResolver.resolveRedisCommandFactory(ExecutableCommandLookupStrategySupport.java:78)
    at io.lettuce.core.dynamic.ExecutableCommandLookupStrategySupport.resolveCommandFactory(ExecutableCommandLookupStrategySupport.java:51)
    at io.lettuce.core.dynamic.AsyncExecutableCommandLookupStrategy.resolveCommandMethod(AsyncExecutableCommandLookupStrategy.java:47)
    at io.lettuce.core.dynamic.RedisCommandFactory$CompositeCommandLookupStrategy.resolveCommandMethod(RedisCommandFactory.java:297)
    at io.lettuce.core.dynamic.RedisCommandFactory$BatchAwareCommandLookupStrategy.resolveCommandMethod(RedisCommandFactory.java:351)
    at io.lettuce.core.dynamic.RedisCommandFactory$CommandFactoryExecutorMethodInterceptor.<init>(RedisCommandFactory.java:220)
    at io.lettuce.core.dynamic.RedisCommandFactory.getCommands(RedisCommandFactory.java:200)
    at REDACTED.commons.database.redis.commands.service.REDACTEDRedisService.buildAgnosticCommandsForConnection(REDACTEDRedisService.java:137)
    at REDACTED.commons.database.redis.commands.service.REDACTEDRedisService.buildSingleConnectionAgnosticCommands(REDACTEDRedisService.java:93)
    at REDACTED.commons.database.redis.commands.service.pool.PooledCommandFactory.create(PooledCommandFactory.java:23)
    at REDACTED.commons.database.redis.commands.service.pool.PooledCommandFactory.create(PooledCommandFactory.java:11)
    at org.apache.commons.pool2.BasePooledObjectFactory.makeObject(BasePooledObjectFactory.java:69)
    at org.apache.commons.pool2.impl.GenericObjectPool.create(GenericObjectPool.java:565)
    at org.apache.commons.pool2.impl.GenericObjectPool.borrowObject(GenericObjectPool.java:307)
    at org.apache.commons.pool2.impl.GenericObjectPool.borrowObject(GenericObjectPool.java:428)
    at org.apache.commons.pool2.impl.GenericObjectPool.borrowObject(GenericObjectPool.java:232)
    at REDACTED.commons.database.redis.commands.service.pool.AutoCloseableObjectsGenericObjectPool.borrowObject(AutoCloseableObjectsGenericObjectPool.java:42)
    at REDACTED.commons.database.redis.commands.service.REDACTEDRedisService.borrowSingleConnectionAgnosticCommandsFromPool(REDACTEDRedisService.java:98)
    at REDACTED.commons.agent.manager.REDACTEDSubscriberManipulationService.fetchIDsFromMsisdnIndex(REDACTEDSubscriberManipulationService.java:93)
    at REDACTED.commons.agent.manager.REDACTEDSubscriberManipulationService.fetchCompleteSubscriber(REDACTEDSubscriberManipulationService.java:333)
    at REDACTED.datamgt.http.controllers.REDACTEDReadSubscriberController.lambda$doPost$0(REDACTEDReadSubscriberController.java:47)
    at java.util.stream.ReferencePipeline$3$1.accept(ReferencePipeline.java:193)
    at java.util.ArrayList$ArrayListSpliterator.forEachRemaining(ArrayList.java:1384)
    at java.util.stream.AbstractPipeline.copyInto(AbstractPipeline.java:482)
    at java.util.stream.AbstractPipeline.wrapAndCopyInto(AbstractPipeline.java:472)
    at java.util.stream.ReduceOps$ReduceOp.evaluateSequential(ReduceOps.java:708)
    at java.util.stream.AbstractPipeline.evaluate(AbstractPipeline.java:234)
    at java.util.stream.ReferencePipeline.collect(ReferencePipeline.java:566)
    at REDACTED.datamgt.http.controllers.REDACTEDReadSubscriberController.doPost(REDACTEDReadSubscriberController.java:58)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:707)
    at REDACTED.libs.utils.httpcontrol.protocols.ServletController.service(ServletController.java:18)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:790)
    at org.eclipse.jetty.servlet.ServletHolder.handle(ServletHolder.java:763)
    at org.eclipse.jetty.servlet.ServletHandler.doHandle(ServletHandler.java:551)
    at org.eclipse.jetty.server.handler.ScopedHandler.nextHandle(ScopedHandler.java:233)
    at org.eclipse.jetty.server.handler.ContextHandler.doHandle(ContextHandler.java:1363)
    at org.eclipse.jetty.server.handler.ScopedHandler.nextScope(ScopedHandler.java:188)
    at org.eclipse.jetty.servlet.ServletHandler.doScope(ServletHandler.java:489)
    at org.eclipse.jetty.server.handler.ScopedHandler.nextScope(ScopedHandler.java:186)
    at org.eclipse.jetty.server.handler.ContextHandler.doScope(ContextHandler.java:1278)
    at org.eclipse.jetty.server.handler.ScopedHandler.handle(ScopedHandler.java:141)
    at org.eclipse.jetty.server.handler.HandlerWrapper.handle(HandlerWrapper.java:127)
    at org.eclipse.jetty.server.Server.handle(Server.java:500)
    at org.eclipse.jetty.server.HttpChannel.lambda$handle$1(HttpChannel.java:383)
    at org.eclipse.jetty.server.HttpChannel.dispatch(HttpChannel.java:547)
    at org.eclipse.jetty.server.HttpChannel.handle(HttpChannel.java:375)
    at org.eclipse.jetty.server.HttpConnection.onFillable(HttpConnection.java:273)
    at org.eclipse.jetty.io.AbstractConnection$ReadCallback.succeeded(AbstractConnection.java:311)
    at org.eclipse.jetty.io.FillInterest.fillable(FillInterest.java:103)
    at org.eclipse.jetty.io.ChannelEndPoint$2.run(ChannelEndPoint.java:117)
    at org.eclipse.jetty.util.thread.QueuedThreadPool.runJob(QueuedThreadPool.java:806)
    at org.eclipse.jetty.util.thread.QueuedThreadPool$Runner.run(QueuedThreadPool.java:938)
    at java.lang.Thread.run(Thread.java:748)

Input Code

Interface:

import io.lettuce.core.dynamic.Commands;
import io.lettuce.core.dynamic.annotation.Command;
import io.lettuce.core.dynamic.annotation.Key;
import io.lettuce.core.dynamic.annotation.Param;
import io.lettuce.core.dynamic.annotation.Value;

import java.util.List;
import java.util.Map;
import java.util.Set;

public interface LettuceRedisStringByteArrayCommands extends Commands {

  @Command("SET")
  @Override
  byte[] set(@Key byte[] key, @Value byte[] value);

  @Command("GET")
  @Override
  byte[] get(@Key byte[] key);

  @Command("UNLINK")
  Long unlink(@Key byte[]... keys);
  
  static Long convertTestDummyMethod(byte[] key) {
      System.out.println("hello");
      return 1L;
  }

}

Factory:

// [add imports]
public class MainClass {
    public static void main(String[] args) {
        // [get a "connection" instance]
        RedisCommandFactory commandFactory = new RedisCommandFactory(connection, Collections.singleton(ByteArrayCodec.INSTANCE));
        LettuceRedisStringByteArrayCommands commandsInstance = commandFactory.getCommands(LettuceRedisStringByteArrayCommands.class);
    }
}

Expected behavior/code

The method should be ignored by the command binding mechanism, just like default methods, and by consequence this exception shouldn't be thrown.

Environment

• Lettuce version(s): 6.0.2.RELEASE and 5.3.2.RELEASE
• Redis version: 6.2.4

Possible Solution

Add method static check to the conditions in DefaultRedisCommandMetadata:

Current:

private boolean isQueryMethodCandidate(Method method) {
    return !method.isBridge() && !method.isDefault();
}

After:

private boolean isQueryMethodCandidate(Method method) {
    return !method.isBridge() && !method.isDefault() && !Modifier.isStatic(method.getModifiers());
}

Additional context

Please don't judge me for using static methods on the interface xD

[henry701]

Thanks!

Also, proposed easy-peazy workaround for those who need it and can't upgrade: Just move the static methods to another class.