Classpath strangeness with 1.0.4+

I am encountering an issue that I cannot find out enough about to really point anybody in a concrete direction.

So let me provide as much information as possible:

I have a multi-project build.sbt that uses sbt 1.1.1.

• project A contains a Kafka Streams dependency
• project B also contains a Kafka Streams dependency (which I do not really need but I like it for clarity rather than transitively) and a dependency on project A via dependsOn in the build.sbt
• project B has specs2 tests

When I issue sbt projectB/test, all tests pass. Then I run sbt project/test again (without changes), I get a stack trace similar to the following:

java.lang.ExceptionInInitializerError
	at org.apache.kafka.streams.KafkaStreams.<init>(KafkaStreams.java:509)
	at com.nequissimus.norm.Foo$.$anonfun$prepare$1(Foo.scala:61)
	at scalaz.effect.IO$.$anonfun$apply$2(IO.scala:178)
	at scalaz.std.FunctionInstances$$anon$1.$anonfun$map$1(Function.scala:77)
	at scalaz.Free.$anonfun$run$1(Free.scala:271)
	at scalaz.Free.go2$1(Free.scala:162)
	at scalaz.Free.go(Free.scala:165)
	at scalaz.Free.run(Free.scala:271)
	at scalaz.effect.IO.unsafePerformIO(IO.scala:22)
	at com.nequissimus.norm.FooSpec.$anonfun$duo2cloudlog$5(FooSpec.scala:61)
	at scala.runtime.java8.JFunction0$mcV$sp.apply(JFunction0$mcV$sp.java:12)
	at scala.concurrent.Future$.$anonfun$apply$1(Future.scala:655)
	at scala.util.Success.$anonfun$map$1(Try.scala:251)
	at scala.util.Success.map(Try.scala:209)
	at scala.concurrent.Future.$anonfun$map$1(Future.scala:289)
	at scala.concurrent.impl.Promise.liftedTree1$1(Promise.scala:29)
	at scala.concurrent.impl.Promise.$anonfun$transform$1(Promise.scala:29)
	at scala.concurrent.impl.CallbackRunnable.run(Promise.scala:60)
	at scala.concurrent.impl.ExecutionContextImpl$AdaptedForkJoinTask.exec(ExecutionContextImpl.scala:140)
	at java.util.concurrent.ForkJoinTask.doExec(ForkJoinTask.java:289)
	at java.util.concurrent.ForkJoinPool$WorkQueue.runTask(ForkJoinPool.java:1056)
	at java.util.concurrent.ForkJoinPool.runWorker(ForkJoinPool.java:1692)
	at java.util.concurrent.ForkJoinWorkerThread.run(ForkJoinWorkerThread.java:157)
Caused by: org.apache.kafka.common.config.ConfigException: Invalid value org.apache.kafka.streams.errors.LogAndFailExceptionHandler for configuration default.deserialization.exception.handler: Class org.apache.kafka.streams.errors.LogAndFailExceptionHandler could not be found.
	at org.apache.kafka.common.config.ConfigDef.parseType(ConfigDef.java:715)
	at org.apache.kafka.common.config.ConfigDef$ConfigKey.<init>(ConfigDef.java:945)
	at org.apache.kafka.common.config.ConfigDef.define(ConfigDef.java:137)
	at org.apache.kafka.common.config.ConfigDef.define(ConfigDef.java:157)
	at org.apache.kafka.common.config.ConfigDef.define(ConfigDef.java:196)
	at org.apache.kafka.common.config.ConfigDef.define(ConfigDef.java:358)
	at org.apache.kafka.common.config.ConfigDef.define(ConfigDef.java:371)
	at org.apache.kafka.streams.StreamsConfig.<clinit>(StreamsConfig.java:309)
	... 23 more

If I change anything inside the test specification (FooSpec) then sbt projectB/test will work again, exactly once.

This issue seems to be new to sbt 1.0.4 (I do not encounter the same problem with 0.13.17 or 1.0.{0, 1, 2, 3} but do with 1.0.4 and 1.1.1; I literally just tried all of these)

The interesting bit (to me) here is that Kafka throws an exception that would typically indicate that an old version of kafka-clients is present. However, nowhere in my dependency tree, such version can be found. So I presume something else is going on that I do not understand (a class unloaded?) This is really beyond my understanding of internals, I hope somebody can make sense of this. I am willing to provide additional information if somebody points me in the right direction.

Unfortunately, I was unable to create a minimal reproduction (I tried).

[eed3si9n]

The interesting bit (to me) here is that Kafka throws an exception that would typically indicate that an old version of kafka-clients is present. However, nowhere in my dependency tree, such version can be found. So I presume something else is going on that I do not understand (a class unloaded?)

Does this go away if you forked the test?

Test / fork := true

[NeQuissimus]

I have not seen this issue in a very long time. I think we can close this issue.