IncompatibleClassChangeError with upickle 1.3.14 and 1.3.15

[lefou]

Here is a stacktrack which running mill with upickle 1.3.15.

java.lang.IncompatibleClassChangeError: Implementing class
  java.lang.ClassLoader.defineClass1(Native Method)
  java.lang.ClassLoader.defineClass(ClassLoader.java:756)
  java.security.SecureClassLoader.defineClass(SecureClassLoader.java:142)
  java.net.URLClassLoader.defineClass(URLClassLoader.java:468)
  java.net.URLClassLoader.access$100(URLClassLoader.java:74)
  java.net.URLClassLoader$1.run(URLClassLoader.java:369)
  java.net.URLClassLoader$1.run(URLClassLoader.java:363)
  java.security.AccessController.doPrivileged(Native Method)
  java.net.URLClassLoader.findClass(URLClassLoader.java:362)
  java.lang.ClassLoader.loadClass(ClassLoader.java:418)
  sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:352)
  java.lang.ClassLoader.loadClass(ClassLoader.java:351)
  ammonite.runtime.Storage$.<clinit>(Storage.scala:110)
  ammonite.runtime.Storage$Folder$$anon$34.apply(Storage.scala:330)
  ammonite.runtime.Storage$Folder$$anon$34.apply(Storage.scala:323)
  ammonite.interp.DependencyLoader.load(DependencyLoader.scala:32)
  ammonite.interp.Interpreter.loadIvy(Interpreter.scala:628)
  ammonite.runtime.ImportHook$BaseIvy.resolve(ImportHook.scala:191)
  mill.main.MillIvyHook$.resolve(MillIvyHook.scala:16)
  ammonite.runtime.ImportHook$BaseIvy.$anonfun$handle$7(ImportHook.scala:200)
  scala.util.Either.flatMap(Either.scala:352)
  ammonite.runtime.ImportHook$BaseIvy.handle(ImportHook.scala:199)
  ammonite.interp.Interpreter.$anonfun$resolveSingleImportHook$4(Interpreter.scala:178)
  ammonite.util.Res$Success.flatMap(Res.scala:62)
  ammonite.interp.Interpreter.resolveSingleImportHook(Interpreter.scala:172)
  ammonite.interp.Interpreter.$anonfun$resolveImportHooks$1(Interpreter.scala:225)
  ammonite.util.Res$.$anonfun$map$1(Res.scala:43)
  ammonite.util.Res$.$anonfun$fold$1(Res.scala:32)
  scala.collection.LinearSeqOps.foldLeft(LinearSeq.scala:169)
  scala.collection.LinearSeqOps.foldLeft$(LinearSeq.scala:165)
  scala.collection.immutable.List.foldLeft(List.scala:79)
  ammonite.util.Res$.fold(Res.scala:30)
  ammonite.util.Res$.map(Res.scala:43)
  ammonite.interp.Interpreter.resolveImportHooks(Interpreter.scala:225)
  ammonite.interp.Interpreter.$anonfun$processAllScriptBlocks$14(Interpreter.scala:583)
  ammonite.util.Res$Success.flatMap(Res.scala:62)
  ammonite.interp.Interpreter.$anonfun$processAllScriptBlocks$12(Interpreter.scala:579)
  scala.Option.getOrElse(Option.scala:201)
  ammonite.interp.Interpreter.loop$1(Interpreter.scala:579)
  ammonite.interp.Interpreter.processAllScriptBlocks(Interpreter.scala:617)
  ammonite.interp.Interpreter.$anonfun$processModule$6(Interpreter.scala:412)
  ammonite.util.Catching.flatMap(Res.scala:115)
  ammonite.interp.Interpreter.$anonfun$processModule$5(Interpreter.scala:403)
  ammonite.util.Res$Success.flatMap(Res.scala:62)
  ammonite.interp.Interpreter.processModule(Interpreter.scala:393)
  ammonite.interp.Interpreter.$anonfun$resolveSingleImportHook$6(Interpreter.scala:184)
  ammonite.util.Res$.$anonfun$map$1(Res.scala:43)
  ammonite.util.Res$.$anonfun$fold$1(Res.scala:32)
  scala.collection.LinearSeqOps.foldLeft(LinearSeq.scala:169)
  scala.collection.LinearSeqOps.foldLeft$(LinearSeq.scala:165)
  scala.collection.immutable.List.foldLeft(List.scala:79)
  ammonite.util.Res$.fold(Res.scala:30)
  ammonite.util.Res$.map(Res.scala:43)
  ammonite.interp.Interpreter.$anonfun$resolveSingleImportHook$5(Interpreter.scala:181)
  ammonite.util.Res$Success.flatMap(Res.scala:62)
  ammonite.interp.Interpreter.$anonfun$resolveSingleImportHook$4(Interpreter.scala:173)
  ammonite.util.Res$Success.flatMap(Res.scala:62)
  ammonite.interp.Interpreter.resolveSingleImportHook(Interpreter.scala:172)
  ammonite.interp.Interpreter.$anonfun$resolveImportHooks$1(Interpreter.scala:225)
  ammonite.util.Res$.$anonfun$map$1(Res.scala:43)
  ammonite.util.Res$.$anonfun$fold$1(Res.scala:32)
  scala.collection.LinearSeqOps.foldLeft(LinearSeq.scala:169)
  scala.collection.LinearSeqOps.foldLeft$(LinearSeq.scala:165)
  scala.collection.immutable.List.foldLeft(List.scala:79)
  ammonite.util.Res$.fold(Res.scala:30)
  ammonite.util.Res$.map(Res.scala:43)
  ammonite.interp.Interpreter.resolveImportHooks(Interpreter.scala:225)
  ammonite.interp.Interpreter.$anonfun$processAllScriptBlocks$14(Interpreter.scala:583)
  ammonite.util.Res$Success.flatMap(Res.scala:62)
  ammonite.interp.Interpreter.$anonfun$processAllScriptBlocks$12(Interpreter.scala:579)
  scala.Option.getOrElse(Option.scala:201)
  ammonite.interp.Interpreter.loop$1(Interpreter.scala:579)
  ammonite.interp.Interpreter.processAllScriptBlocks(Interpreter.scala:617)
  ammonite.interp.Interpreter.$anonfun$processModule$6(Interpreter.scala:412)
  ammonite.util.Catching.flatMap(Res.scala:115)
  ammonite.interp.Interpreter.$anonfun$processModule$5(Interpreter.scala:403)
  ammonite.util.Res$Success.flatMap(Res.scala:62)
  ammonite.interp.Interpreter.processModule(Interpreter.scala:393)
  mill.main.RunScript$.$anonfun$evaluateRootModule$1(RunScript.scala:94)
  ammonite.util.Res$Success.flatMap(Res.scala:62)
  mill.main.RunScript$.evaluateRootModule(RunScript.scala:87)
  mill.main.RunScript$.runScript(RunScript.scala:49)
  mill.main.MainRunner.$anonfun$runScript$1(MainRunner.scala:119)
  mill.main.MainRunner.watchLoop2(MainRunner.scala:68)
  mill.main.MainRunner.runScript(MainRunner.scala:94)
  mill.MillMain$.main0(MillMain.scala:299)
  mill.MillMain$.main(MillMain.scala:104)
  mill.MillMain.main(MillMain.scala)

How to reproduce:

• checkout mill repo, e.g. from tag 0.9.8
• change the upickle depenency version in build.sc line 100 to either 1.3.14 or 1.3.15
• run the following: mill -i dev.assembly && rm -rf ~/.mill && out/dev/assembly/dest/mill -i main.test

This is probably because mill loads plugins via $ivy import which are build with older versions of upickle.

[lihaoyi]

@lefou IIRC uPickle has some binary incompatibility when #348 landed; looking at the stack trace, it looks like you may need to bump Ammonite to a more recent version that uses the latest version of uPickle

[lefou]

Without bumping the major version, no tool can help avoid this kind of issues. Maybe, you can cut a new major release, and restore binary compatibility in a new micro release?

[lihaoyi]

We haven't been following strict semver - normally this kind of bin-compat breakage would bump the second number, and only "huge" source-compat breakages would bump the first. I can go push tags for uPickle and Ammonite to get numbered versions out

[lefou]

We haven't been following strict semver - normally this kind of bin-compat breakage would bump the second number, and only "huge" source-compat breakages would bump the first.

Yeah, I'm aware of that. But maybe upickle should follow semver more stricktly, as it's users community grows.

I can go push tags for uPickle and Ammonite to get numbered versions out.

That would be great! People demand using the repl from Mill with newer Scala versions, and having proper released upstream dependencies would make it much easier to create a new (binary incompatible) mill release (with it's own plugin ecosystem).

[lihaoyi]

uPickle 1.4.0 and Ammonite 2.4.0 are out; they should work together if we want to bump them both in Mill

[lefou]

@lihaoyi Thank you! I'll update those in mill too.