Assembly fails for version >= 0.30.0 with "deduplicate: different file contents found in the following" error

[jfuentescpp]

In order to reproduce:

build.sbt

name := "assembly_conflict"
version := "0.0.1"
scalaVersion := "2.12.11"

libraryDependencies ++= List(
  "com.lightstep.tracer" % "lightstep-tracer-jre" % "0.30.1",
  "com.lightstep.tracer" % "tracer-grpc" % "0.30.0",
  "io.grpc" % "grpc-netty" % "1.23.0",
  "io.netty" % "netty-tcnative-boringssl-static" % "2.0.25.Final",
  "org.slf4j" % "slf4j-simple" % "1.7.25"
)

project/plugins.sbt

addSbtPlugin("com.eed3si9n" % "sbt-assembly" % "0.15.0")

project/build.properties

sbt.version=1.1.1

then sbt assembly give erros:

[error] 13 errors were encountered during merge
[error] java.lang.RuntimeException: deduplicate: different file contents found in the following:
[error] /Users/jfuentes/.ivy2/cache/io.netty/netty-buffer/jars/netty-buffer-4.1.38.Final.jar:META-INF/io.netty.versions.properties
[error] /Users/jfuentes/.ivy2/cache/io.netty/netty-codec-http/jars/netty-codec-http-4.1.38.Final.jar:META-INF/io.netty.versions.properties
[error] /Users/jfuentes/.ivy2/cache/io.netty/netty-codec-http2/jars/netty-codec-http2-4.1.38.Final.jar:META-INF/io.netty.versions.properties
[error] /Users/jfuentes/.ivy2/cache/io.netty/netty-codec-socks/jars/netty-codec-socks-4.1.38.Final.jar:META-INF/io.netty.versions.properties
[error] /Users/jfuentes/.ivy2/cache/io.netty/netty-codec/jars/netty-codec-4.1.38.Final.jar:META-INF/io.netty.versions.properties
[error] /Users/jfuentes/.ivy2/cache/io.netty/netty-common/jars/netty-common-4.1.38.Final.jar:META-INF/io.netty.versions.properties
[error] /Users/jfuentes/.ivy2/cache/io.netty/netty-handler-proxy/jars/netty-handler-proxy-4.1.38.Final.jar:META-INF/io.netty.versions.properties
[error] /Users/jfuentes/.ivy2/cache/io.netty/netty-handler/jars/netty-handler-4.1.38.Final.jar:META-INF/io.netty.versions.properties
[error] /Users/jfuentes/.ivy2/cache/io.netty/netty-resolver/jars/netty-resolver-4.1.38.Final.jar:META-INF/io.netty.versions.properties
[error] /Users/jfuentes/.ivy2/cache/io.netty/netty-tcnative-boringssl-static/jars/netty-tcnative-boringssl-static-2.0.25.Final.jar:META-INF/io.netty.versions.properties
[error] /Users/jfuentes/.ivy2/cache/io.netty/netty-transport/jars/netty-transport-4.1.38.Final.jar:META-INF/io.netty.versions.properties
[error] deduplicate: different file contents found in the following:
[error] /Users/jfuentes/.ivy2/cache/com.lightstep.tracer/java-common/jars/java-common-0.30.0.jar:com/lightstep/tracer/grpc/Collector$1.class
[error] /Users/jfuentes/.ivy2/cache/com.lightstep.tracer/java-metrics-reporter/jars/java-metrics-reporter-0.1.4.jar:com/lightstep/tracer/grpc/Collector$1.class
[error] deduplicate: different file contents found in the following:
[error] /Users/jfuentes/.ivy2/cache/com.lightstep.tracer/java-common/jars/java-common-0.30.0.jar:com/lightstep/tracer/grpc/Collector.class
[error] /Users/jfuentes/.ivy2/cache/com.lightstep.tracer/java-metrics-reporter/jars/java-metrics-reporter-0.1.4.jar:com/lightstep/tracer/grpc/Collector.class
[error] deduplicate: different file contents found in the following:
[error] /Users/jfuentes/.ivy2/cache/com.lightstep.tracer/java-common/jars/java-common-0.30.0.jar:com/lightstep/tracer/grpc/KeyValue$1.class
[error] /Users/jfuentes/.ivy2/cache/com.lightstep.tracer/java-metrics-reporter/jars/java-metrics-reporter-0.1.4.jar:com/lightstep/tracer/grpc/KeyValue$1.class
[error] deduplicate: different file contents found in the following:
[error] /Users/jfuentes/.ivy2/cache/com.lightstep.tracer/java-common/jars/java-common-0.30.0.jar:com/lightstep/tracer/grpc/KeyValue$2.class
[error] /Users/jfuentes/.ivy2/cache/com.lightstep.tracer/java-metrics-reporter/jars/java-metrics-reporter-0.1.4.jar:com/lightstep/tracer/grpc/KeyValue$2.class
[error] deduplicate: different file contents found in the following:
[error] /Users/jfuentes/.ivy2/cache/com.lightstep.tracer/java-common/jars/java-common-0.30.0.jar:com/lightstep/tracer/grpc/KeyValue$Builder.class
[error] /Users/jfuentes/.ivy2/cache/com.lightstep.tracer/java-metrics-reporter/jars/java-metrics-reporter-0.1.4.jar:com/lightstep/tracer/grpc/KeyValue$Builder.class
[error] deduplicate: different file contents found in the following:
[error] /Users/jfuentes/.ivy2/cache/com.lightstep.tracer/java-common/jars/java-common-0.30.0.jar:com/lightstep/tracer/grpc/KeyValue$ValueCase.class
[error] /Users/jfuentes/.ivy2/cache/com.lightstep.tracer/java-metrics-reporter/jars/java-metrics-reporter-0.1.4.jar:com/lightstep/tracer/grpc/KeyValue$ValueCase.class
[error] deduplicate: different file contents found in the following:
[error] /Users/jfuentes/.ivy2/cache/com.lightstep.tracer/java-common/jars/java-common-0.30.0.jar:com/lightstep/tracer/grpc/KeyValue.class
[error] /Users/jfuentes/.ivy2/cache/com.lightstep.tracer/java-metrics-reporter/jars/java-metrics-reporter-0.1.4.jar:com/lightstep/tracer/grpc/KeyValue.class
[error] deduplicate: different file contents found in the following:
[error] /Users/jfuentes/.ivy2/cache/com.lightstep.tracer/java-common/jars/java-common-0.30.0.jar:com/lightstep/tracer/grpc/KeyValueOrBuilder.class
[error] /Users/jfuentes/.ivy2/cache/com.lightstep.tracer/java-metrics-reporter/jars/java-metrics-reporter-0.1.4.jar:com/lightstep/tracer/grpc/KeyValueOrBuilder.class
[error] deduplicate: different file contents found in the following:
[error] /Users/jfuentes/.ivy2/cache/com.lightstep.tracer/java-common/jars/java-common-0.30.0.jar:com/lightstep/tracer/grpc/Reporter$1.class
[error] /Users/jfuentes/.ivy2/cache/com.lightstep.tracer/java-metrics-reporter/jars/java-metrics-reporter-0.1.4.jar:com/lightstep/tracer/grpc/Reporter$1.class
[error] deduplicate: different file contents found in the following:
[error] /Users/jfuentes/.ivy2/cache/com.lightstep.tracer/java-common/jars/java-common-0.30.0.jar:com/lightstep/tracer/grpc/Reporter$Builder.class
[error] /Users/jfuentes/.ivy2/cache/com.lightstep.tracer/java-metrics-reporter/jars/java-metrics-reporter-0.1.4.jar:com/lightstep/tracer/grpc/Reporter$Builder.class
[error] deduplicate: different file contents found in the following:
[error] /Users/jfuentes/.ivy2/cache/com.lightstep.tracer/java-common/jars/java-common-0.30.0.jar:com/lightstep/tracer/grpc/Reporter.class
[error] /Users/jfuentes/.ivy2/cache/com.lightstep.tracer/java-metrics-reporter/jars/java-metrics-reporter-0.1.4.jar:com/lightstep/tracer/grpc/Reporter.class
[error] deduplicate: different file contents found in the following:
[error] /Users/jfuentes/.ivy2/cache/com.lightstep.tracer/java-common/jars/java-common-0.30.0.jar:com/lightstep/tracer/grpc/ReporterOrBuilder.class
[error] /Users/jfuentes/.ivy2/cache/com.lightstep.tracer/java-metrics-reporter/jars/java-metrics-reporter-0.1.4.jar:com/lightstep/tracer/grpc/ReporterOrBuilder.class
[error]         at sbtassembly.Assembly$.applyStrategies(Assembly.scala:161)
[error]         at sbtassembly.Assembly$.x$1$lzycompute$1(Assembly.scala:43)
[error]         at sbtassembly.Assembly$.x$1$1(Assembly.scala:41)
[error]         at sbtassembly.Assembly$.stratMapping$lzycompute$1(Assembly.scala:41)
[error]         at sbtassembly.Assembly$.stratMapping$1(Assembly.scala:41)
[error]         at sbtassembly.Assembly$.inputs$lzycompute$1(Assembly.scala:86)
[error]         at sbtassembly.Assembly$.inputs$1(Assembly.scala:76)
[error]         at sbtassembly.Assembly$.apply(Assembly.scala:103)
[error]         at sbtassembly.Assembly$.$anonfun$assemblyTask$1(Assembly.scala:278)
[error]         at scala.Function1.$anonfun$compose$1(Function1.scala:44)
[error]         at sbt.internal.util.$tilde$greater.$anonfun$$u2219$1(TypeFunctions.scala:39)
[error]         at sbt.std.Transform$$anon$4.work(System.scala:66)
[error]         at sbt.Execute.$anonfun$submit$2(Execute.scala:262)
[error]         at sbt.internal.util.ErrorHandling$.wideConvert(ErrorHandling.scala:16)
[error]         at sbt.Execute.work(Execute.scala:271)
[error]         at sbt.Execute.$anonfun$submit$1(Execute.scala:262)
[error]         at sbt.ConcurrentRestrictions$$anon$4.$anonfun$submitValid$1(ConcurrentRestrictions.scala:174)
[error]         at sbt.CompletionService$$anon$2.call(CompletionService.scala:36)
[error]         at java.util.concurrent.FutureTask.run(FutureTask.java:266)
[error]         at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511)
[error]         at java.util.concurrent.FutureTask.run(FutureTask.java:266)
[error]         at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
[error]         at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
[error]         at java.lang.Thread.run(Thread.java:748)
[error] (assembly) deduplicate: different file contents found in the following:
[error] /Users/jfuentes/.ivy2/cache/io.netty/netty-buffer/jars/netty-buffer-4.1.38.Final.jar:META-INF/io.netty.versions.properties
[error] /Users/jfuentes/.ivy2/cache/io.netty/netty-codec-http/jars/netty-codec-http-4.1.38.Final.jar:META-INF/io.netty.versions.properties
[error] /Users/jfuentes/.ivy2/cache/io.netty/netty-codec-http2/jars/netty-codec-http2-4.1.38.Final.jar:META-INF/io.netty.versions.properties
[error] /Users/jfuentes/.ivy2/cache/io.netty/netty-codec-socks/jars/netty-codec-socks-4.1.38.Final.jar:META-INF/io.netty.versions.properties
[error] /Users/jfuentes/.ivy2/cache/io.netty/netty-codec/jars/netty-codec-4.1.38.Final.jar:META-INF/io.netty.versions.properties
[error] /Users/jfuentes/.ivy2/cache/io.netty/netty-common/jars/netty-common-4.1.38.Final.jar:META-INF/io.netty.versions.properties
[error] /Users/jfuentes/.ivy2/cache/io.netty/netty-handler-proxy/jars/netty-handler-proxy-4.1.38.Final.jar:META-INF/io.netty.versions.properties
[error] /Users/jfuentes/.ivy2/cache/io.netty/netty-handler/jars/netty-handler-4.1.38.Final.jar:META-INF/io.netty.versions.properties
[error] /Users/jfuentes/.ivy2/cache/io.netty/netty-resolver/jars/netty-resolver-4.1.38.Final.jar:META-INF/io.netty.versions.properties
[error] /Users/jfuentes/.ivy2/cache/io.netty/netty-tcnative-boringssl-static/jars/netty-tcnative-boringssl-static-2.0.25.Final.jar:META-INF/io.netty.versions.properties
[error] /Users/jfuentes/.ivy2/cache/io.netty/netty-transport/jars/netty-transport-4.1.38.Final.jar:META-INF/io.netty.versions.properties
[error] deduplicate: different file contents found in the following:
[error] /Users/jfuentes/.ivy2/cache/com.lightstep.tracer/java-common/jars/java-common-0.30.0.jar:com/lightstep/tracer/grpc/Collector$1.class
[error] /Users/jfuentes/.ivy2/cache/com.lightstep.tracer/java-metrics-reporter/jars/java-metrics-reporter-0.1.4.jar:com/lightstep/tracer/grpc/Collector$1.class
[error] deduplicate: different file contents found in the following:
[error] /Users/jfuentes/.ivy2/cache/com.lightstep.tracer/java-common/jars/java-common-0.30.0.jar:com/lightstep/tracer/grpc/Collector.class
[error] /Users/jfuentes/.ivy2/cache/com.lightstep.tracer/java-metrics-reporter/jars/java-metrics-reporter-0.1.4.jar:com/lightstep/tracer/grpc/Collector.class
[error] deduplicate: different file contents found in the following:
[error] /Users/jfuentes/.ivy2/cache/com.lightstep.tracer/java-common/jars/java-common-0.30.0.jar:com/lightstep/tracer/grpc/KeyValue$1.class
[error] /Users/jfuentes/.ivy2/cache/com.lightstep.tracer/java-metrics-reporter/jars/java-metrics-reporter-0.1.4.jar:com/lightstep/tracer/grpc/KeyValue$1.class
[error] deduplicate: different file contents found in the following:
[error] /Users/jfuentes/.ivy2/cache/com.lightstep.tracer/java-common/jars/java-common-0.30.0.jar:com/lightstep/tracer/grpc/KeyValue$2.class
[error] /Users/jfuentes/.ivy2/cache/com.lightstep.tracer/java-metrics-reporter/jars/java-metrics-reporter-0.1.4.jar:com/lightstep/tracer/grpc/KeyValue$2.class
[error] deduplicate: different file contents found in the following:
[error] /Users/jfuentes/.ivy2/cache/com.lightstep.tracer/java-common/jars/java-common-0.30.0.jar:com/lightstep/tracer/grpc/KeyValue$Builder.class
[error] /Users/jfuentes/.ivy2/cache/com.lightstep.tracer/java-metrics-reporter/jars/java-metrics-reporter-0.1.4.jar:com/lightstep/tracer/grpc/KeyValue$Builder.class
[error] deduplicate: different file contents found in the following:
[error] /Users/jfuentes/.ivy2/cache/com.lightstep.tracer/java-common/jars/java-common-0.30.0.jar:com/lightstep/tracer/grpc/KeyValue$ValueCase.class
[error] /Users/jfuentes/.ivy2/cache/com.lightstep.tracer/java-metrics-reporter/jars/java-metrics-reporter-0.1.4.jar:com/lightstep/tracer/grpc/KeyValue$ValueCase.class
[error] deduplicate: different file contents found in the following:
[error] /Users/jfuentes/.ivy2/cache/com.lightstep.tracer/java-common/jars/java-common-0.30.0.jar:com/lightstep/tracer/grpc/KeyValue.class
[error] /Users/jfuentes/.ivy2/cache/com.lightstep.tracer/java-metrics-reporter/jars/java-metrics-reporter-0.1.4.jar:com/lightstep/tracer/grpc/KeyValue.class
[error] deduplicate: different file contents found in the following:
[error] /Users/jfuentes/.ivy2/cache/com.lightstep.tracer/java-common/jars/java-common-0.30.0.jar:com/lightstep/tracer/grpc/KeyValueOrBuilder.class
[error] /Users/jfuentes/.ivy2/cache/com.lightstep.tracer/java-metrics-reporter/jars/java-metrics-reporter-0.1.4.jar:com/lightstep/tracer/grpc/KeyValueOrBuilder.class
[error] deduplicate: different file contents found in the following:
[error] /Users/jfuentes/.ivy2/cache/com.lightstep.tracer/java-common/jars/java-common-0.30.0.jar:com/lightstep/tracer/grpc/Reporter$1.class
[error] /Users/jfuentes/.ivy2/cache/com.lightstep.tracer/java-metrics-reporter/jars/java-metrics-reporter-0.1.4.jar:com/lightstep/tracer/grpc/Reporter$1.class
[error] deduplicate: different file contents found in the following:
[error] /Users/jfuentes/.ivy2/cache/com.lightstep.tracer/java-common/jars/java-common-0.30.0.jar:com/lightstep/tracer/grpc/Reporter$Builder.class
[error] /Users/jfuentes/.ivy2/cache/com.lightstep.tracer/java-metrics-reporter/jars/java-metrics-reporter-0.1.4.jar:com/lightstep/tracer/grpc/Reporter$Builder.class
[error] deduplicate: different file contents found in the following:
[error] /Users/jfuentes/.ivy2/cache/com.lightstep.tracer/java-common/jars/java-common-0.30.0.jar:com/lightstep/tracer/grpc/Reporter.class
[error] /Users/jfuentes/.ivy2/cache/com.lightstep.tracer/java-metrics-reporter/jars/java-metrics-reporter-0.1.4.jar:com/lightstep/tracer/grpc/Reporter.class
[error] deduplicate: different file contents found in the following:
[error] /Users/jfuentes/.ivy2/cache/com.lightstep.tracer/java-common/jars/java-common-0.30.0.jar:com/lightstep/tracer/grpc/ReporterOrBuilder.class
[error] /Users/jfuentes/.ivy2/cache/com.lightstep.tracer/java-metrics-reporter/jars/java-metrics-reporter-0.1.4.jar:com/lightstep/tracer/grpc/ReporterOrBuilder.class
[error] Total time: 8 s, completed Aug 12, 2020 12:58:41 PM

Issue can be worked around with something like code below. It worked fine before 0.30.0 release.

assemblyMergeStrategy in assembly := {
  case PathList("com", "lightstep", "tracer", "grpc", xs @ _*) =>
    MergeStrategy.first
  case x => MergeStrategy.defaultMergeStrategy(x)
}

Checking the dependency tree, the conflict is from libraries that lightstep-tracer-jre depends:

Why is this error happening? Content of the source code seems quite similar but I didn't properly check. Some difference in the .class?