Crash when defining AnyVal values in REPL (due to java.lang.ClassNotFoundException)

[j-mie6]

Compiler version

Version 3.2.2

Reproduction steps

Start a Scala 3 REPL session:

$ scala -classpath "$(cs fetch -p com.github.j-mie6::parsley:4.2.10)"

In this session:

scala> import parsley.Parsley.*
scala> val p = pure(6)

Output (click arrow to expand)

Exception in thread "main" java.lang.ClassNotFoundException: Parsley
        at dotty.tools.repl.AbstractFileClassLoader.findClass(AbstractFileClassLoader.scala:51)
        at java.base/java.lang.ClassLoader.loadClass(ClassLoader.java:587)
        at java.base/java.lang.ClassLoader.loadClass(ClassLoader.java:520)
        at dotty.tools.repl.AbstractFileClassLoader.loadClass(AbstractFileClassLoader.scala:57)
        at java.base/java.lang.Class.forName0(Native Method)
        at java.base/java.lang.Class.forName(Class.java:467)
        at dotty.tools.repl.Rendering.rewrapValueClass(Rendering.scala:135)
        at dotty.tools.repl.Rendering.$anonfun$4(Rendering.scala:114)
        at scala.Option.flatMap(Option.scala:283)
        at dotty.tools.repl.Rendering.valueOf(Rendering.scala:114)
        at dotty.tools.repl.Rendering.renderVal(Rendering.scala:157)
        at dotty.tools.repl.ReplDriver.$anonfun$7(ReplDriver.scala:365)
        at scala.runtime.function.JProcedure1.apply(JProcedure1.java:15)
        at scala.runtime.function.JProcedure1.apply(JProcedure1.java:10)
        at scala.collection.immutable.List.foreach(List.scala:333)
        at dotty.tools.repl.ReplDriver.extractAndFormatMembers$1(ReplDriver.scala:371)
        at dotty.tools.repl.ReplDriver.renderDefinitions$$anonfun$2(ReplDriver.scala:403)
        at scala.Option.map(Option.scala:242)
        at dotty.tools.repl.ReplDriver.renderDefinitions(ReplDriver.scala:409)
        at dotty.tools.repl.ReplDriver.compile$$anonfun$2(ReplDriver.scala:307)
        at scala.util.Either.fold(Either.scala:189)
        at dotty.tools.repl.ReplDriver.compile(ReplDriver.scala:323)
        at dotty.tools.repl.ReplDriver.interpret(ReplDriver.scala:248)
        at dotty.tools.repl.ReplDriver.loop$1(ReplDriver.scala:168)
        at dotty.tools.repl.ReplDriver.runUntilQuit$$anonfun$1(ReplDriver.scala:171)
        at dotty.tools.repl.ReplDriver.withRedirectedOutput(ReplDriver.scala:191)
        at dotty.tools.repl.ReplDriver.runBody$$anonfun$1(ReplDriver.scala:179)
        at dotty.tools.runner.ScalaClassLoader$.asContext(ScalaClassLoader.scala:80)
        at dotty.tools.repl.ReplDriver.runBody(ReplDriver.scala:179)
        at dotty.tools.repl.ReplDriver.runUntilQuit(ReplDriver.scala:171)
        at dotty.tools.repl.ReplDriver.tryRunning(ReplDriver.scala:133)
        at dotty.tools.repl.Main$.main(Main.scala:7)
        at dotty.tools.MainGenericRunner$.run$1(MainGenericRunner.scala:193)
        at dotty.tools.MainGenericRunner$.process(MainGenericRunner.scala:270)
        at dotty.tools.MainGenericRunner$.main(MainGenericRunner.scala:281)
        at dotty.tools.MainGenericRunner.main(MainGenericRunner.scala)
        at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
        at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:77)
        at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
        at java.base/java.lang.reflect.Method.invoke(Method.java:568)
        at coursier.bootstrap.launcher.a.a(Unknown Source)
        at coursier.bootstrap.launcher.Launcher.main(Unknown Source)

Additional information

This is not a problem with the Scala 2.13 REPL. Use of a lazy val prevents the crash:

scala> import parsley.Parsley.*
scala> lazy val p = pure(6)
scala> p.parse("") // works!
scala> p               // crashes as above!

However, if p is printed at any point this causes the crash. For context, the class in question is defined as:

final class Parsley[+A] private [parsley] (private [parsley] val internal: frontend.LazyParsley[A]) extends AnyVal

Making it an AnyVal class (this appears to be referenced within the stack trace).

With Scala 2.13 evaluating p in the REPL produces the output:

val p:  parsley.Parsley[Int] = parsley.Parsley@4392362c

[som-snytt]

I asked tardily in the chat room whether it was tried on nightly. Here is local publication that works.

Apparently, dotty is still one step ahead of us.

➜  snips scala-cli --scala 3.3.1-RC1-bin-SNAPSHOT --dependency com.github.j-mie6::parsley:4.2.10
Welcome to Scala 3.3.1-RC1-bin-SNAPSHOT-git-fe08f5f (20.0.1, Java OpenJDK 64-Bit Server VM).
Type in expressions for evaluation. Or try :help.

scala> import parsley.*, character.*, combinator.*, Parsley.*

scala> val rps: Parsley[List[Char]] = string("recordParserString") *> space *> some(noneOf('\n')) <* optional(char('\n'))
val rps: parsley.Parsley[List[Char]] = parsley.Parsley@1002b06d

scala> rps
val res0: parsley.Parsley[List[Char]] = parsley.Parsley@1002b06d

scala> val p = pure(6)
val p: parsley.Parsley[Int] = parsley.Parsley@3922b297

scala> p.parse("")
val res1: parsley.Result[String, Int] = Success(6)

scala> p
val res2: parsley.Parsley[Int] = parsley.Parsley@3922b297

scala>

[som-snytt]

231f9ab

Duplicates #16322

So the knock-on effect of delayed releases is duplicate ticketing.