maxInboundMessageSize is not applied when app code has newer gRPC version than used in library

What version of gRPC-Java are you using?

Library compiled with gRPC 1.26.0 (cannot be recompiled on demand) Application must use a newer version (>= 1.34), gRPC 1.39.0

What is your environment?

Linux, OpenJDK 15

What did you expect to see?

Custom maxInboundMessageSize value (!= 4 MiB) is applied and works correctly

What did you see instead?

Status{code=CLIENT_RESOURCE_EXHAUSTED, issues=[gRPC error: (RESOURCE_EXHAUSTED) gRPC message exceeds maximum size 4194304: 14995791 (S_ERROR)]}

Steps to reproduce the bug

1. Compile library code with gRPC 1.26.0

import io.grpc.ManagedChannelBuilder;
import io.grpc.netty.NettyChannelBuilder;

public class Lib {
  private final NettyChannelBuilder ncb;

  public Lib() {
    ncb = NettyChannelBuilder
        .forTarget("localhost:100")
        .maxInboundMessageSize(100);
  }

  public NettyChannelBuilder getBuilder() {
    return ncb;
  }
}

1. Compile application, using the compiled library, with gRPC 1.39.0

import java.lang.reflect.Field;
import io.grpc.netty.NettyChannelBuilder;
import io.grpc.internal.AbstractManagedChannelImplBuilder;

public class Client {

  public static void main(String[] args) throws Exception {
    NettyChannelBuilder ncb = new Lib().getBuilder();
    // reflection is used to create a minimal example showing the problem - 
    // no need to create a real channel, start the server, etc.
    Field f = ncb.getClass().getDeclaredField("maxInboundMessageSize");
    f.setAccessible(true);
    System.out.println(f.get(ncb));
  }
}

1. Run compiled Client with gRPC 1.39.0 in the classpath. The program will print 4194304 but value 100 expected.

It seems this behavior was caused by fixing issue #7552

[ejona86]

BTW, @marx-freedom, good job tracking the issue down to the clear reproduction steps. I’m sure it was very confusing.

[sergiitk]

Hey @marx-freedom! Good news, I tracked down exact root causes, and fixed the issue. After the fix is released, and you update your application code, maxInboundMessageSize(int) will be working correctly.