Coursier: shading breaking scala pickling

[fommil]

check out this PR https://github.com/ensime/ensime-sbt/pull/312

and run sbt scripted sbt-ensime/different-scalaorganization

 [info] [info] Compiling 1 Scala source to /tmp/sbt_33fe5332/different-scalaorganization/project/target/scala-2.10/sbt-0.13/classes...
[error] error: bad symbolic reference. A signature in EnsimeCoursierKeys.class refers to term coursier
[error] in package <root> which is not available.

I've isolated it to the use of addEnsimeScalaPlugin

the full stacktrace is...

[info]  at scala.reflect.internal.pickling.UnPickler$Scan.toTypeError(UnPickler.scala:847)
[info]  at scala.reflect.internal.pickling.UnPickler$Scan$LazyTypeRef.complete(UnPickler.scala:854)
[info]  at scala.reflect.internal.Symbols$Symbol.info(Symbols.scala:1231)
[info]  at scala.reflect.internal.Types$TypeMap$$anonfun$noChangeToSymbols$1.apply(Types.scala:4280)
[info]  at scala.reflect.internal.Types$TypeMap$$anonfun$noChangeToSymbols$1.apply(Types.scala:4280)
[info]  at scala.collection.LinearSeqOptimized$class.forall(LinearSeqOptimized.scala:70)
[info]  at scala.collection.immutable.List.forall(List.scala:84)
[info]  at scala.reflect.internal.Types$TypeMap.noChangeToSymbols(Types.scala:4280)
[info]  at scala.reflect.internal.Types$TypeMap.mapOver(Types.scala:4293)
[info]  at scala.reflect.internal.Types$TypeMap.mapOver(Types.scala:4231)
[info]  at scala.reflect.internal.Types$adaptToNewRunMap$.apply(Types.scala:5249)
[info]  at scala.reflect.internal.Types$adaptToNewRunMap$.apply(Types.scala:5130)
[info]  at scala.collection.immutable.List.loop$1(List.scala:170)
[info]  at scala.collection.immutable.List.mapConserve(List.scala:186)
[info]  at scala.reflect.internal.Types$adaptToNewRunMap$.apply(Types.scala:5199)
[info]  at scala.reflect.internal.Types$adaptToNewRunMap$.apply(Types.scala:5222)
[info]  at scala.reflect.internal.pickling.UnPickler$Scan$LazyTypeRef.complete(UnPickler.scala:858)
[info]  at scala.reflect.internal.pickling.UnPickler$Scan$LazyTypeRef.load(UnPickler.scala:863)
[info]  at scala.reflect.internal.Symbols$Symbol.typeParams(Symbols.scala:1489)
[info]  at scala.tools.nsc.transform.SpecializeTypes$$anonfun$scala$tools$nsc$transform$SpecializeTypes$$normalizeMember$1.apply(SpecializeTypes.scala:798)
[info]  at scala.tools.nsc.transform.SpecializeTypes$$anonfun$scala$tools$nsc$transform$SpecializeTypes$$normalizeMember$1.apply(SpecializeTypes.scala:798)
[info]  at scala.reflect.internal.SymbolTable.atPhase(SymbolTable.scala:207)
[info]  at scala.reflect.internal.SymbolTable.beforePhase(SymbolTable.scala:215)
[info]  at scala.tools.nsc.transform.SpecializeTypes.scala$tools$nsc$transform$SpecializeTypes$$normalizeMember(SpecializeTypes.scala:797)
[info]  at scala.tools.nsc.transform.SpecializeTypes$$anonfun$22.apply(SpecializeTypes.scala:751)
[info]  at scala.tools.nsc.transform.SpecializeTypes$$anonfun$22.apply(SpecializeTypes.scala:749)
[info]  at scala.collection.TraversableLike$$anonfun$flatMap$1.apply(TraversableLike.scala:251)
[info]  at scala.collection.TraversableLike$$anonfun$flatMap$1.apply(TraversableLike.scala:251)
[info]  at scala.collection.immutable.List.foreach(List.scala:318)
[info]  at scala.collection.TraversableLike$class.flatMap(TraversableLike.scala:251)
[info]  at scala.collection.AbstractTraversable.flatMap(Traversable.scala:105)
[info]  at scala.tools.nsc.transform.SpecializeTypes.specializeClass(SpecializeTypes.scala:749)
[info]  at scala.tools.nsc.transform.SpecializeTypes.transformInfo(SpecializeTypes.scala:1172)
[info]  at scala.tools.nsc.transform.InfoTransform$Phase$$anon$1.transform(InfoTransform.scala:38)
[info]  at scala.reflect.internal.Symbols$Symbol.rawInfo(Symbols.scala:1321)
[info]  at scala.reflect.internal.Symbols$Symbol.info(Symbols.scala:1241)
[info]  at scala.reflect.internal.Symbols$Symbol.isDerivedValueClass(Symbols.scala:658)
[info]  at scala.reflect.internal.Symbols$Symbol.isMethodWithExtension(Symbols.scala:661)
[info]  at scala.tools.nsc.transform.Erasure$ErasureTransformer$$anon$1.preEraseNormalApply(Erasure.scala:1100)
[info]  at scala.tools.nsc.transform.Erasure$ErasureTransformer$$anon$1.preEraseApply(Erasure.scala:1195)
[info]  at scala.tools.nsc.transform.Erasure$ErasureTransformer$$anon$1.preErase(Erasure.scala:1205)
[info]  at scala.tools.nsc.transform.Erasure$ErasureTransformer$$anon$1.transform(Erasure.scala:1280)
[info]  at scala.tools.nsc.transform.Erasure$ErasureTransformer$$anon$1.transform(Erasure.scala:1030)
[info]  at scala.reflect.internal.Trees$class.itransform(Trees.scala:1217)
[info]  at scala.reflect.internal.SymbolTable.itransform(SymbolTable.scala:13)
[info]  at scala.reflect.internal.SymbolTable.itransform(SymbolTable.scala:13)
[info]  at scala.reflect.api.Trees$Transformer.transform(Trees.scala:2897)
[info]  at scala.tools.nsc.transform.TypingTransformers$TypingTransformer.transform(TypingTransformers.scala:48)
[info]  at scala.tools.nsc.transform.Erasure$ErasureTransformer$$anon$1.transform(Erasure.scala:1292)
[info]  at scala.tools.nsc.transform.Erasure$ErasureTransformer$$anon$1.transform(Erasure.scala:1030)
[info]  at scala.reflect.internal.Trees$class.itransform(Trees.scala:1219)
[info]  at scala.reflect.internal.SymbolTable.itransform(SymbolTable.scala:13)
[info]  at scala.reflect.internal.SymbolTable.itransform(SymbolTable.scala:13)
[info]  at scala.reflect.api.Trees$Transformer.transform(Trees.scala:2897)
[info]  at scala.tools.nsc.transform.TypingTransformers$TypingTransformer.transform(TypingTransformers.scala:48)
[info]  at scala.tools.nsc.transform.Erasure$ErasureTransformer$$anon$1.transform(Erasure.scala:1292)
[info]  at scala.tools.nsc.transform.Erasure$ErasureTransformer$$anon$1.transform(Erasure.scala:1030)
[info]  at scala.reflect.api.Trees$Transformer$$anonfun$transformTrees$1.apply(Trees.scala:2900)
[info]  at scala.reflect.api.Trees$Transformer$$anonfun$transformTrees$1.apply(Trees.scala:2900)
[info]  at scala.collection.immutable.List.loop$1(List.scala:170)
[info]  at scala.collection.immutable.List.mapConserve(List.scala:186)
[info]  at scala.reflect.api.Trees$Transformer.transformTrees(Trees.scala:2900)
[info]  at scala.reflect.internal.Trees$class.itransform(Trees.scala:1219)
[info]  at scala.reflect.internal.SymbolTable.itransform(SymbolTable.scala:13)
[info]  at scala.reflect.internal.SymbolTable.itransform(SymbolTable.scala:13)
[info]  at scala.reflect.api.Trees$Transformer.transform(Trees.scala:2897)
[info]  at scala.tools.nsc.transform.TypingTransformers$TypingTransformer.transform(TypingTransformers.scala:48)
[info]  at scala.tools.nsc.transform.Erasure$ErasureTransformer$$anon$1.transform(Erasure.scala:1292)
[info]  at scala.tools.nsc.transform.Erasure$ErasureTransformer$$anon$1.transform(Erasure.scala:1030)
[info]  at scala.reflect.internal.Trees$$anonfun$itransform$2.apply(Trees.scala:1235)
[info]  at scala.reflect.internal.Trees$$anonfun$itransform$2.apply(Trees.scala:1233)
[info]  at scala.reflect.api.Trees$Transformer.atOwner(Trees.scala:2936)
[info]  at scala.tools.nsc.transform.TypingTransformers$TypingTransformer.atOwner(TypingTransformers.scala:34)
[info]  at scala.tools.nsc.transform.TypingTransformers$TypingTransformer.atOwner(TypingTransformers.scala:28)
[info]  at scala.tools.nsc.transform.TypingTransformers$TypingTransformer.atOwner(TypingTransformers.scala:19)
[info]  at scala.reflect.internal.Trees$class.itransform(Trees.scala:1232)
[info]  at scala.reflect.internal.SymbolTable.itransform(SymbolTable.scala:13)
[info]  at scala.reflect.internal.SymbolTable.itransform(SymbolTable.scala:13)
[info]  at scala.reflect.api.Trees$Transformer.transform(Trees.scala:2897)
[info]  at scala.tools.nsc.transform.TypingTransformers$TypingTransformer.transform(TypingTransformers.scala:48)
[info]  at scala.tools.nsc.transform.Erasure$ErasureTransformer$$anon$1.transform(Erasure.scala:1288)
[info]  at scala.tools.nsc.transform.Erasure$ErasureTransformer$$anon$1.transform(Erasure.scala:1030)
[info]  at scala.reflect.api.Trees$Transformer$$anonfun$transformStats$1.apply(Trees.scala:2927)
[info]  at scala.reflect.api.Trees$Transformer$$anonfun$transformStats$1.apply(Trees.scala:2925)
[info]  at scala.collection.immutable.List.loop$1(List.scala:170)
[info]  at scala.collection.immutable.List.mapConserve(List.scala:186)
[info]  at scala.reflect.api.Trees$Transformer.transformStats(Trees.scala:2925)
[info]  at scala.reflect.internal.Trees$class.itransform(Trees.scala:1276)
[info]  at scala.reflect.internal.SymbolTable.itransform(SymbolTable.scala:13)
[info]  at scala.reflect.internal.SymbolTable.itransform(SymbolTable.scala:13)
[info]  at scala.reflect.api.Trees$Transformer.transform(Trees.scala:2897)
[info]  at scala.tools.nsc.transform.TypingTransformers$TypingTransformer.scala$tools$nsc$transform$TypingTransformers$TypingTransformer$$super$transform(TypingTransformers.scala:44)
[info]  at scala.tools.nsc.transform.TypingTransformers$TypingTransformer$$anonfun$transform$1.apply(TypingTransformers.scala:44)
[info]  at scala.tools.nsc.transform.TypingTransformers$TypingTransformer$$anonfun$transform$1.apply(TypingTransformers.scala:44)
[info]  at scala.reflect.api.Trees$Transformer.atOwner(Trees.scala:2936)
[info]  at scala.tools.nsc.transform.TypingTransformers$TypingTransformer.atOwner(TypingTransformers.scala:34)
[info]  at scala.tools.nsc.transform.TypingTransformers$TypingTransformer.transform(TypingTransformers.scala:44)
[info]  at scala.tools.nsc.transform.Erasure$ErasureTransformer$$anon$1.transform(Erasure.scala:1292)
[info]  at scala.tools.nsc.transform.Erasure$ErasureTransformer$$anon$1.transform(Erasure.scala:1030)
[info]  at scala.reflect.api.Trees$Transformer.transformTemplate(Trees.scala:2904)
[info]  at scala.reflect.internal.Trees$$anonfun$itransform$4.apply(Trees.scala:1280)
[info]  at scala.reflect.internal.Trees$$anonfun$itransform$4.apply(Trees.scala:1279)
[info]  at scala.reflect.api.Trees$Transformer.atOwner(Trees.scala:2936)
[info]  at scala.tools.nsc.transform.TypingTransformers$TypingTransformer.atOwner(TypingTransformers.scala:34)
[info]  at scala.tools.nsc.transform.TypingTransformers$TypingTransformer.atOwner(TypingTransformers.scala:28)
[info]  at scala.tools.nsc.transform.TypingTransformers$TypingTransformer.atOwner(TypingTransformers.scala:19)
[info]  at scala.reflect.internal.Trees$class.itransform(Trees.scala:1278)
[info]  at scala.reflect.internal.SymbolTable.itransform(SymbolTable.scala:13)
[info]  at scala.reflect.internal.SymbolTable.itransform(SymbolTable.scala:13)
[info]  at scala.reflect.api.Trees$Transformer.transform(Trees.scala:2897)
[info]  at scala.tools.nsc.transform.TypingTransformers$TypingTransformer.transform(TypingTransformers.scala:48)
[info]  at scala.tools.nsc.transform.Erasure$ErasureTransformer$$anon$1.transform(Erasure.scala:1292)
[info]  at scala.tools.nsc.transform.Erasure$ErasureTransformer$$anon$1.transform(Erasure.scala:1030)
[info]  at scala.reflect.api.Trees$Transformer$$anonfun$transformStats$1.apply(Trees.scala:2927)
[info]  at scala.reflect.api.Trees$Transformer$$anonfun$transformStats$1.apply(Trees.scala:2925)
[info]  at scala.collection.immutable.List.loop$1(List.scala:170)
[info]  at scala.collection.immutable.List.mapConserve(List.scala:186)
[info]  at scala.reflect.api.Trees$Transformer.transformStats(Trees.scala:2925)
[info]  at scala.reflect.internal.Trees$$anonfun$itransform$7.apply(Trees.scala:1298)
[info]  at scala.reflect.internal.Trees$$anonfun$itransform$7.apply(Trees.scala:1298)
[info]  at scala.reflect.api.Trees$Transformer.atOwner(Trees.scala:2936)
[info]  at scala.tools.nsc.transform.TypingTransformers$TypingTransformer.atOwner(TypingTransformers.scala:34)
[info]  at scala.tools.nsc.transform.TypingTransformers$TypingTransformer.atOwner(TypingTransformers.scala:28)
[info]  at scala.tools.nsc.transform.TypingTransformers$TypingTransformer.atOwner(TypingTransformers.scala:19)
[info]  at scala.reflect.internal.Trees$class.itransform(Trees.scala:1297)
[info]  at scala.reflect.internal.SymbolTable.itransform(SymbolTable.scala:13)
[info]  at scala.reflect.internal.SymbolTable.itransform(SymbolTable.scala:13)
[info]  at scala.reflect.api.Trees$Transformer.transform(Trees.scala:2897)
[info]  at scala.tools.nsc.transform.TypingTransformers$TypingTransformer.scala$tools$nsc$transform$TypingTransformers$TypingTransformer$$super$transform(TypingTransformers.scala:44)
[info]  at scala.tools.nsc.transform.TypingTransformers$TypingTransformer$$anonfun$transform$2.apply(TypingTransformers.scala:46)
[info]  at scala.tools.nsc.transform.TypingTransformers$TypingTransformer$$anonfun$transform$2.apply(TypingTransformers.scala:46)
[info]  at scala.reflect.api.Trees$Transformer.atOwner(Trees.scala:2936)
[info]  at scala.tools.nsc.transform.TypingTransformers$TypingTransformer.atOwner(TypingTransformers.scala:34)
[info]  at scala.tools.nsc.transform.TypingTransformers$TypingTransformer.transform(TypingTransformers.scala:46)
[info]  at scala.tools.nsc.transform.Erasure$ErasureTransformer$$anon$1.transform(Erasure.scala:1292)
[info]  at scala.tools.nsc.transform.Erasure$ErasureTransformer.transform(Erasure.scala:1302)
[info]  at scala.tools.nsc.transform.Erasure$ErasureTransformer.transform(Erasure.scala:888)
[info]  at scala.tools.nsc.ast.Trees$Transformer.transformUnit(Trees.scala:227)
[info]  at scala.tools.nsc.transform.Transform$Phase.apply(Transform.scala:30)
[info]  at scala.tools.nsc.Global$GlobalPhase.applyPhase(Global.scala:464)
[info]  at scala.tools.nsc.Global$GlobalPhase$$anonfun$run$1.apply(Global.scala:431)
[info]  at scala.tools.nsc.Global$GlobalPhase$$anonfun$run$1.apply(Global.scala:431)
[info]  at scala.collection.Iterator$class.foreach(Iterator.scala:727)
[info]  at scala.collection.AbstractIterator.foreach(Iterator.scala:1157)
[info]  at scala.tools.nsc.Global$GlobalPhase.run(Global.scala:431)
[info]  at sbt.compiler.Eval$$anonfun$compile$1$1.apply$mcV$sp(Eval.scala:177)
[info]  at sbt.compiler.Eval$$anonfun$compile$1$1.apply(Eval.scala:177)
[info]  at sbt.compiler.Eval$$anonfun$compile$1$1.apply(Eval.scala:177)
[info]  at scala.reflect.internal.SymbolTable.atPhase(SymbolTable.scala:207)
[info]  at sbt.compiler.Eval.compile$1(Eval.scala:177)
[info]  at sbt.compiler.Eval.compileAndLoad(Eval.scala:182)
[info]  at sbt.compiler.Eval.evalCommon(Eval.scala:152)
[info]  at sbt.compiler.Eval.eval(Eval.scala:96)
[info]  at sbt.EvaluateConfigurations$.evaluateDslEntry(EvaluateConfigurations.scala:177)
[info]  at sbt.EvaluateConfigurations$$anonfun$9.apply(EvaluateConfigurations.scala:117)
[info]  at sbt.EvaluateConfigurations$$anonfun$9.apply(EvaluateConfigurations.scala:115)
[info]  at scala.collection.TraversableLike$$anonfun$map$1.apply(TraversableLike.scala:244)
[info]  at scala.collection.TraversableLike$$anonfun$map$1.apply(TraversableLike.scala:244)
[info]  at scala.collection.immutable.List.foreach(List.scala:318)
[info]  at scala.collection.TraversableLike$class.map(TraversableLike.scala:244)
[info]  at scala.collection.AbstractTraversable.map(Traversable.scala:105)
[info]  at sbt.EvaluateConfigurations$.evaluateSbtFile(EvaluateConfigurations.scala:115)
[info]  at sbt.Load$.sbt$Load$$loadSettingsFile$1(Load.scala:775)
[info]  at sbt.Load$$anonfun$sbt$Load$$memoLoadSettingsFile$1$1.apply(Load.scala:781)
[info]  at sbt.Load$$anonfun$sbt$Load$$memoLoadSettingsFile$1$1.apply(Load.scala:780)
[info]  at scala.collection.MapLike$class.getOrElse(MapLike.scala:128)
[info]  at scala.collection.AbstractMap.getOrElse(Map.scala:58)
[info]  at sbt.Load$.sbt$Load$$memoLoadSettingsFile$1(Load.scala:780)
[info]  at sbt.Load$$anonfun$loadFiles$1$2.apply(Load.scala:788)
[info]  at sbt.Load$$anonfun$loadFiles$1$2.apply(Load.scala:788)
[info]  at scala.collection.TraversableLike$$anonfun$map$1.apply(TraversableLike.scala:244)
[info]  at scala.collection.TraversableLike$$anonfun$map$1.apply(TraversableLike.scala:244)
[info]  at scala.collection.mutable.ResizableArray$class.foreach(ResizableArray.scala:59)
[info]  at scala.collection.mutable.ArrayBuffer.foreach(ArrayBuffer.scala:47)
[info]  at scala.collection.TraversableLike$class.map(TraversableLike.scala:244)
[info]  at scala.collection.AbstractTraversable.map(Traversable.scala:105)
[info]  at sbt.Load$.loadFiles$1(Load.scala:788)
[info]  at sbt.Load$.discoverProjects(Load.scala:799)
[info]  at sbt.Load$.discover$1(Load.scala:585)
[info]  at sbt.Load$.sbt$Load$$loadTransitive(Load.scala:633)
[info]  at sbt.Load$$anonfun$loadUnit$1.sbt$Load$$anonfun$$loadProjects$1(Load.scala:482)
[info]  at sbt.Load$$anonfun$loadUnit$1$$anonfun$40.apply(Load.scala:485)
[info]  at sbt.Load$$anonfun$loadUnit$1$$anonfun$40.apply(Load.scala:485)
[info]  at sbt.Load$.timed(Load.scala:1025)
[info]  at sbt.Load$$anonfun$loadUnit$1.apply(Load.scala:485)
[info]  at sbt.Load$$anonfun$loadUnit$1.apply(Load.scala:459)
[info]  at sbt.Load$.timed(Load.scala:1025)
[info]  at sbt.Load$.loadUnit(Load.scala:459)
[info]  at sbt.Load$$anonfun$25$$anonfun$apply$14.apply(Load.scala:311)
[info]  at sbt.Load$$anonfun$25$$anonfun$apply$14.apply(Load.scala:310)
[info]  at sbt.BuildLoader$$anonfun$componentLoader$1$$anonfun$apply$4$$anonfun$apply$5$$anonfun$apply$6.apply(BuildLoader.scala:91)
[info]  at sbt.BuildLoader$$anonfun$componentLoader$1$$anonfun$apply$4$$anonfun$apply$5$$anonfun$apply$6.apply(BuildLoader.scala:90)
[info]  at sbt.BuildLoader.apply(BuildLoader.scala:140)
[info]  at sbt.Load$.loadAll(Load.scala:365)
[info]  at sbt.Load$.loadURI(Load.scala:320)
[info]  at sbt.Load$.load(Load.scala:316)
[info]  at sbt.Load$.load(Load.scala:305)
[info]  at sbt.Load$$anonfun$4.apply(Load.scala:146)
[info]  at sbt.Load$$anonfun$4.apply(Load.scala:146)
[info]  at sbt.Load$.timed(Load.scala:1025)
[info]  at sbt.Load$.apply(Load.scala:146)
[info]  at sbt.Load$.defaultLoad(Load.scala:39)
[info]  at sbt.BuiltinCommands$.liftedTree1$1(Main.scala:496)
[info]  at sbt.BuiltinCommands$.doLoadProject(Main.scala:496)
[info]  at sbt.BuiltinCommands$$anonfun$loadProjectImpl$2.apply(Main.scala:488)
[info]  at sbt.BuiltinCommands$$anonfun$loadProjectImpl$2.apply(Main.scala:488)
[info]  at sbt.Command$$anonfun$applyEffect$1$$anonfun$apply$2.apply(Command.scala:59)
[info]  at sbt.Command$$anonfun$applyEffect$1$$anonfun$apply$2.apply(Command.scala:59)
[info]  at sbt.Command$$anonfun$applyEffect$2$$anonfun$apply$3.apply(Command.scala:61)
[info]  at sbt.Command$$anonfun$applyEffect$2$$anonfun$apply$3.apply(Command.scala:61)
[info]  at sbt.Command$.process(Command.scala:93)
[info]  at sbt.MainLoop$$anonfun$1$$anonfun$apply$1.apply(MainLoop.scala:96)
[info]  at sbt.MainLoop$$anonfun$1$$anonfun$apply$1.apply(MainLoop.scala:96)
[info]  at sbt.State$$anon$1.process(State.scala:184)
[info]  at sbt.MainLoop$$anonfun$1.apply(MainLoop.scala:96)
[info]  at sbt.MainLoop$$anonfun$1.apply(MainLoop.scala:96)
[info]  at sbt.ErrorHandling$.wideConvert(ErrorHandling.scala:17)
[info]  at sbt.MainLoop$.next(MainLoop.scala:96)
[info]  at sbt.MainLoop$.run(MainLoop.scala:89)
[info]  at sbt.MainLoop$$anonfun$runWithNewLog$1.apply(MainLoop.scala:68)
[info]  at sbt.MainLoop$$anonfun$runWithNewLog$1.apply(MainLoop.scala:63)
[info]  at sbt.Using.apply(Using.scala:24)
[info]  at sbt.MainLoop$.runWithNewLog(MainLoop.scala:63)
[info]  at sbt.MainLoop$.runAndClearLast(MainLoop.scala:46)
[info]  at sbt.MainLoop$.runLoggedLoop(MainLoop.scala:30)
[info]  at sbt.MainLoop$.runLogged(MainLoop.scala:22)
[info]  at sbt.StandardMain$.runManaged(Main.scala:57)
[info]  at sbt.xMain.run(Main.scala:29)
[info]  at xsbt.boot.Launch$$anonfun$run$1.apply(Launch.scala:109)
[info]  at xsbt.boot.Launch$.withContextLoader(Launch.scala:128)
[info]  at xsbt.boot.Launch$.run(Launch.scala:109)
[info]  at xsbt.boot.Launch$$anonfun$apply$1.apply(Launch.scala:35)
[info]  at xsbt.boot.Launch$.launch(Launch.scala:117)
[info]  at xsbt.boot.Launch$.apply(Launch.scala:18)
[info]  at xsbt.boot.Boot$.runImpl(Boot.scala:41)
[info]  at xsbt.boot.Boot$.main(Boot.scala:17)
[info]  at xsbt.boot.Boot.main(Boot.scala)
[info] [error] scala.reflect.internal.Types$TypeError: bad symbolic reference. A signature in EnsimeCoursierPlugin.class refers to term core
[info] [error] in value coursier which is not available.
[info] [error] It may be completely missing from the current classpath, or the version on
[info] [error] the classpath might be incompatible with the version used when compiling EnsimeCoursierPlugin.class.

[jvican]

I've run into this issue too. I'm afraid there's no easy fix.

One cannot depend on a Scala-compiled shaded artifact. Shaded artifacts are only meant for its direct use but cannot be recycled for compilation. The issue is that shaded artifacts, as produced by sbt-shading and assembly, only do ASM transformations, leaving the pickling information untouched (in the ScalaSignature annotation).

What happens when you depend on such a shaded jar is that whenever you use it, scalac will try to unpickle that information and will see that the namespaces do not exist (because they've been shaded).

The only reasonable fix to this is to write a tool that shadows also the pickled information. I may consider writing such a tool since this is a realy key issue for me as a sbt plugin maintainer. I'm saddened that plugin classloading in sbt was so bad well thought.

A workaround for this issue, as I was discussing yesterday with @fommil, is to use the classes provided by the shaded jar but never expose them to the public Java interface. That means putting them as private or changing the method signatures so that there's no trace of them. This is not as easy as it may seem and creates ugly code. I think the only way to move forward is to shade also in the pickled information.

[dwijnand]

@jvican

1. :+1: on a scala-aware shader, I'm sure it's been on the TODO lists of a few people. It would be a useful tool to have.

2. Feel free to open an issue to track sbt plugin isolation.

[s1ck]

@jvican there is https://github.com/hutkev/ScalaShade

It basically decodes the signature and updates references recursively. It worked for simple Scala (case) classes. However, I tried to update the signatures of a relocated cats library ... it fails on package objects. But maybe it's already sufficient for your use case.

[alexarchambault]

Seems jar-jar-abrams fixes that.