This project is created to show the problem of shading Scala library, particularly Akka DNS.
Run the following to reproduce the problem.
sbt hello/compile
Conversely, the following runs just fine.
sbt boom/run
The project hello is a simple hello-world like project, which depends on the shaded Akka DNS.
The shaded Akka DNS is built using shaded-akka-dns project which will product a jar file containing only shaded classes from the Akka DNS library (i.e. transitive dependencies are not included). SBT Assembly is used to package and shade the Akka DNS library. SBT Assembly also provides the means to post-process the reference.conf contained within Akka DNS jar to ensure the shaded classes is used in the config file.
Similarly, the project boom is a simple hello-world like project, which depends on the shaded Log4J.
The shaded Log4J is built using shaded-log4j project which will product a jar file containing only shaded classes from the Log4J library (i.e. transitive dependencies are not included).
When compiling against shaded Akka DNS jar, we've found the following compile failure.
$ sbt hello/compile
[info] Loading settings from plugins.sbt ...
[info] Loading global plugins from /Users/felixsatyaputra/.sbt/1.0/plugins
[info] Loading settings from plugins.sbt ...
[info] Loading project definition from /Users/felixsatyaputra/workspace/typesafe-fsat/shading-scala-repro/project
[info] Loading settings from build.sbt ...
[info] Set current project to root (in build file:/Users/felixsatyaputra/workspace/typesafe-fsat/shading-scala-repro/)
[info] Including from cache: akka-dns_2.11-2.4.2.jar
[info] Checking every *.class/*.jar file's SHA-1.
[info] Merging files...
[info] Packaging /Users/felixsatyaputra/workspace/typesafe-fsat/shading-scala-repro/shaded-akka-dns/target/2.12/shaded-akka-dns-2.12-0.1-SNAPSHOT.jar ...
[info] Done packaging.
[info] Compiling 1 Scala source to /Users/felixsatyaputra/workspace/typesafe-fsat/shading-scala-repro/hello/target/scala-2.12/classes ...
[error] /Users/felixsatyaputra/workspace/typesafe-fsat/shading-scala-repro/hello/src/main/scala/Hello.scala:1:42: object AsyncDnsResolver is not a member of package com.lightbend.rp.internal.akka.io
[error] Note: class AsyncDnsResolver exists, but it has no companion object.
[error] import com.lightbend.rp.internal.akka.io.AsyncDnsResolver.SrvResolved
[error] ^
[error] /Users/felixsatyaputra/workspace/typesafe-fsat/shading-scala-repro/hello/src/main/scala/Hello.scala:2:8: Symbol 'term <none>.dns.raw' is missing from the classpath.
[error] This symbol is required by ' <none>'.
[error] Make sure that term raw is in your classpath and check for conflicting dependencies with `-Ylog-classpath`.
[error] A full rebuild may help if 'package.class' was compiled against an incompatible version of <none>.dns.
[error] import com.lightbend.rp.internal.ru.smslv.akka.dns.raw.SRVRecord
[error] ^
[error] two errors found
[error] (hello/compile:compileIncremental) Compilation failed
[error] Total time: 1 s, completed 18/12/2017 1:53:13 PM
The generated shaded-akka-dns-2.12-0.1-SNAPSHOT.jar does contain all classes from the Akka DNS library.
$ jar tvf /Users/felixsatyaputra/workspace/typesafe-fsat/shading-scala-repro/shaded-akka-dns/target/2.12/shaded-akka-dns-2.12-0.1-SNAPSHOT.jar
300 Mon Dec 18 13:53:12 AEDT 2017 META-INF/MANIFEST.MF
0 Mon Dec 18 13:53:12 AEDT 2017 com/
0 Mon Dec 18 13:53:12 AEDT 2017 com/lightbend/
0 Mon Dec 18 13:53:12 AEDT 2017 com/lightbend/rp/
0 Mon Dec 18 13:53:12 AEDT 2017 com/lightbend/rp/internal/
0 Mon Dec 18 13:53:12 AEDT 2017 com/lightbend/rp/internal/akka/
0 Mon Dec 18 13:53:12 AEDT 2017 com/lightbend/rp/internal/akka/io/
0 Mon Dec 18 13:53:12 AEDT 2017 com/lightbend/rp/internal/ru/
0 Mon Dec 18 13:53:12 AEDT 2017 com/lightbend/rp/internal/ru/smslv/
0 Mon Dec 18 13:53:12 AEDT 2017 com/lightbend/rp/internal/ru/smslv/akka/
0 Mon Dec 18 13:53:12 AEDT 2017 com/lightbend/rp/internal/ru/smslv/akka/dns/
0 Mon Dec 18 13:53:12 AEDT 2017 com/lightbend/rp/internal/ru/smslv/akka/dns/raw/
1479 Mon Dec 18 13:52:28 AEDT 2017 com/lightbend/rp/internal/akka/io/AsyncDnsResolver$$anonfun$11$$anonfun$apply$1.class
2455 Mon Dec 18 13:52:28 AEDT 2017 com/lightbend/rp/internal/akka/io/AsyncDnsResolver$$anonfun$11.class
1895 Mon Dec 18 13:52:28 AEDT 2017 com/lightbend/rp/internal/akka/io/AsyncDnsResolver$$anonfun$12.class
1439 Mon Dec 18 13:52:28 AEDT 2017 com/lightbend/rp/internal/akka/io/AsyncDnsResolver$$anonfun$16$$anonfun$apply$2.class
1480 Mon Dec 18 13:52:28 AEDT 2017 com/lightbend/rp/internal/akka/io/AsyncDnsResolver$$anonfun$16$$anonfun$apply$3.class
2013 Mon Dec 18 13:52:28 AEDT 2017 com/lightbend/rp/internal/akka/io/AsyncDnsResolver$$anonfun$16.class
1119 Mon Dec 18 13:52:28 AEDT 2017 com/lightbend/rp/internal/akka/io/AsyncDnsResolver$$anonfun$parseNameserverAddress$1.class
1510 Mon Dec 18 13:52:28 AEDT 2017 com/lightbend/rp/internal/akka/io/AsyncDnsResolver$$anonfun$parseNameserverAddress$2.class
1271 Mon Dec 18 13:52:28 AEDT 2017 com/lightbend/rp/internal/akka/io/AsyncDnsResolver$$anonfun$receive$1$$anonfun$1.class
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1822 Mon Dec 18 13:52:28 AEDT 2017 com/lightbend/rp/internal/akka/io/AsyncDnsResolver$$anonfun$receive$1$$anonfun$14.class
1823 Mon Dec 18 13:52:28 AEDT 2017 com/lightbend/rp/internal/akka/io/AsyncDnsResolver$$anonfun$receive$1$$anonfun$15.class
1507 Mon Dec 18 13:52:28 AEDT 2017 com/lightbend/rp/internal/akka/io/AsyncDnsResolver$$anonfun$receive$1$$anonfun$2.class
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1507 Mon Dec 18 13:52:28 AEDT 2017 com/lightbend/rp/internal/akka/io/AsyncDnsResolver$$anonfun$receive$1$$anonfun$4.class
1271 Mon Dec 18 13:52:28 AEDT 2017 com/lightbend/rp/internal/akka/io/AsyncDnsResolver$$anonfun$receive$1$$anonfun$5.class
1508 Mon Dec 18 13:52:28 AEDT 2017 com/lightbend/rp/internal/akka/io/AsyncDnsResolver$$anonfun$receive$1$$anonfun$6.class
2831 Mon Dec 18 13:52:28 AEDT 2017 com/lightbend/rp/internal/akka/io/AsyncDnsResolver$$anonfun$receive$1$$anonfun$7.class
2841 Mon Dec 18 13:52:28 AEDT 2017 com/lightbend/rp/internal/akka/io/AsyncDnsResolver$$anonfun$receive$1$$anonfun$8.class
2844 Mon Dec 18 13:52:28 AEDT 2017 com/lightbend/rp/internal/akka/io/AsyncDnsResolver$$anonfun$receive$1$$anonfun$9.class
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1844 Mon Dec 18 13:52:28 AEDT 2017 com/lightbend/rp/internal/akka/io/AsyncDnsResolver$$anonfun$receive$1$$anonfun$applyOrElse$4.class
1845 Mon Dec 18 13:52:28 AEDT 2017 com/lightbend/rp/internal/akka/io/AsyncDnsResolver$$anonfun$receive$1$$anonfun$applyOrElse$5.class
1845 Mon Dec 18 13:52:28 AEDT 2017 com/lightbend/rp/internal/akka/io/AsyncDnsResolver$$anonfun$receive$1$$anonfun$applyOrElse$6.class
1845 Mon Dec 18 13:52:28 AEDT 2017 com/lightbend/rp/internal/akka/io/AsyncDnsResolver$$anonfun$receive$1$$anonfun$applyOrElse$7.class
16537 Mon Dec 18 13:52:28 AEDT 2017 com/lightbend/rp/internal/akka/io/AsyncDnsResolver$$anonfun$receive$1.class
5761 Mon Dec 18 13:52:28 AEDT 2017 com/lightbend/rp/internal/akka/io/AsyncDnsResolver$.class
4305 Mon Dec 18 13:52:28 AEDT 2017 com/lightbend/rp/internal/akka/io/AsyncDnsResolver$CurrentRequest$.class
6483 Mon Dec 18 13:52:28 AEDT 2017 com/lightbend/rp/internal/akka/io/AsyncDnsResolver$CurrentRequest.class
2735 Mon Dec 18 13:52:28 AEDT 2017 com/lightbend/rp/internal/akka/io/AsyncDnsResolver$SrvResolved$.class
3639 Mon Dec 18 13:52:28 AEDT 2017 com/lightbend/rp/internal/akka/io/AsyncDnsResolver$SrvResolved.class
15980 Mon Dec 18 13:52:28 AEDT 2017 com/lightbend/rp/internal/akka/io/AsyncDnsResolver.class
1456 Mon Dec 18 13:52:28 AEDT 2017 com/lightbend/rp/internal/ru/smslv/akka/dns/AsyncDnsProvider.class
2620 Mon Dec 18 13:52:28 AEDT 2017 com/lightbend/rp/internal/ru/smslv/akka/dns/raw/AAAARecord$.class
6829 Mon Dec 18 13:52:28 AEDT 2017 com/lightbend/rp/internal/ru/smslv/akka/dns/raw/AAAARecord.class
2595 Mon Dec 18 13:52:28 AEDT 2017 com/lightbend/rp/internal/ru/smslv/akka/dns/raw/ARecord$.class
6790 Mon Dec 18 13:52:28 AEDT 2017 com/lightbend/rp/internal/ru/smslv/akka/dns/raw/ARecord.class
2560 Mon Dec 18 13:52:28 AEDT 2017 com/lightbend/rp/internal/ru/smslv/akka/dns/raw/Answer$.class
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9383 Mon Dec 18 13:52:28 AEDT 2017 com/lightbend/rp/internal/ru/smslv/akka/dns/raw/DnsClient.class
1251 Mon Dec 18 13:52:28 AEDT 2017 com/lightbend/rp/internal/ru/smslv/akka/dns/raw/DomainName$$anonfun$parse$1.class
1590 Mon Dec 18 13:52:28 AEDT 2017 com/lightbend/rp/internal/ru/smslv/akka/dns/raw/DomainName$$anonfun$write$1$$anonfun$apply$1.class
1918 Mon Dec 18 13:52:28 AEDT 2017 com/lightbend/rp/internal/ru/smslv/akka/dns/raw/DomainName$$anonfun$write$1.class
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1182 Mon Dec 18 13:52:28 AEDT 2017 com/lightbend/rp/internal/ru/smslv/akka/dns/raw/DomainName.class
1740 Mon Dec 18 13:52:28 AEDT 2017 com/lightbend/rp/internal/ru/smslv/akka/dns/raw/Message$$anonfun$1.class
1770 Mon Dec 18 13:52:28 AEDT 2017 com/lightbend/rp/internal/ru/smslv/akka/dns/raw/Message$$anonfun$2.class
1770 Mon Dec 18 13:52:28 AEDT 2017 com/lightbend/rp/internal/ru/smslv/akka/dns/raw/Message$$anonfun$3.class
1770 Mon Dec 18 13:52:28 AEDT 2017 com/lightbend/rp/internal/ru/smslv/akka/dns/raw/Message$$anonfun$4.class
1622 Mon Dec 18 13:52:28 AEDT 2017 com/lightbend/rp/internal/ru/smslv/akka/dns/raw/Message$$anonfun$write$1.class
1646 Mon Dec 18 13:52:28 AEDT 2017 com/lightbend/rp/internal/ru/smslv/akka/dns/raw/Message$$anonfun$write$2.class
1646 Mon Dec 18 13:52:28 AEDT 2017 com/lightbend/rp/internal/ru/smslv/akka/dns/raw/Message$$anonfun$write$3.class
1646 Mon Dec 18 13:52:28 AEDT 2017 com/lightbend/rp/internal/ru/smslv/akka/dns/raw/Message$$anonfun$write$4.class
6135 Mon Dec 18 13:52:28 AEDT 2017 com/lightbend/rp/internal/ru/smslv/akka/dns/raw/Message$.class
11217 Mon Dec 18 13:52:28 AEDT 2017 com/lightbend/rp/internal/ru/smslv/akka/dns/raw/Message.class
7010 Mon Dec 18 13:52:28 AEDT 2017 com/lightbend/rp/internal/ru/smslv/akka/dns/raw/MessageFlags$.class
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1968 Mon Dec 18 13:52:28 AEDT 2017 com/lightbend/rp/internal/ru/smslv/akka/dns/raw/RecordClass$.class
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2944 Mon Dec 18 13:52:28 AEDT 2017 com/lightbend/rp/internal/ru/smslv/akka/dns/raw/SRVRecord$.class
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7225 Mon Dec 18 13:52:28 AEDT 2017 com/lightbend/rp/internal/ru/smslv/akka/dns/raw/UnknownRecord.class
682 Mon Dec 18 13:52:28 AEDT 2017 com/lightbend/rp/internal/ru/smslv/akka/dns/raw/package$.class
762 Mon Dec 18 13:52:28 AEDT 2017 com/lightbend/rp/internal/ru/smslv/akka/dns/raw/package.class
1178 Mon Dec 18 13:53:12 AEDT 2017 reference.conf