Can't get constructor of java defined class in reflect api

[goshacodes]

Compiler version

3.3.0

Description

I'm trying to extend a java class using reflect api.
To create a symbol for a class I need parent, either TypeTree or Term. TypeTree is not working here, so I'am trying to get a constructor and apply nulls as arguments

Minimized code

public class JavaClassWithBridgeMethod {
    public String overloadedMethod(String a) { return "bar1"; }
}

def macro[T: Type](using quotes: Quotes): Expr[Any] =
  import quotes.reflect.*
  val tpe = TypeRepr.of[T]
  ...

macro[JavaClassWithBridgeMethod]

When I'm trying to use tpe.typeSymbol.primaryConstructor compiler crushes with this:

[error] java.lang.AssertionError: assertion failed: private constructor JavaClassWithBridgeMethod in class JavaClassWithBridgeMethod in /Users/g.kovalev/IdeaProjects/ScalaMock/jvm/src/test/java/com/paulbutcher/test/JavaClassWithBridgeMethod.java accessed from constructor $anon in /Users/g.kovalev/IdeaProjects/ScalaMock/jvm/src/test/scala/com.paulbutcher.test/mock/JavaMocksTest.scala
[error] scala.runtime.Scala3RunTime$.assertFailed(Scala3RunTime.scala:8)
[error] dotty.tools.dotc.transform.ExpandPrivate.ensurePrivateAccessible(ExpandPrivate.scala:88)
[error] dotty.tools.dotc.transform.ExpandPrivate.transformSelect(ExpandPrivate.scala:98)
[error] dotty.tools.dotc.transform.ExpandPrivate.transformSelect(ExpandPrivate.scala:97)
[error] dotty.tools.dotc.transform.MegaPhase.goSelect(MegaPhase.scala:605)
[error] dotty.tools.dotc.transform.MegaPhase.transformNamed$1(MegaPhase.scala:228)
[error] dotty.tools.dotc.transform.MegaPhase.transformTree(MegaPhase.scala:425)
[error] dotty.tools.dotc.transform.MegaPhase.transformUnnamed$1(MegaPhase.scala:278)
[error] dotty.tools.dotc.transform.MegaPhase.transformTree(MegaPhase.scala:427)
[error] dotty.tools.dotc.transform.MegaPhase.loop$2(MegaPhase.scala:444)
[error] dotty.tools.dotc.transform.MegaPhase.transformBlock(MegaPhase.scala:449)
[error] dotty.tools.dotc.transform.MegaPhase.transformUnnamed$1(MegaPhase.scala:298)
[error] dotty.tools.dotc.transform.MegaPhase.transformTree(MegaPhase.scala:427)
[error] dotty.tools.dotc.transform.MegaPhase.mapDefDef$1(MegaPhase.scala:248)
[error] dotty.tools.dotc.transform.MegaPhase.transformNamed$1(MegaPhase.scala:251)
[error] dotty.tools.dotc.transform.MegaPhase.transformTree(MegaPhase.scala:425)
[error] dotty.tools.dotc.transform.MegaPhase.transformSpecificTree(MegaPhase.scala:434)
[error] dotty.tools.dotc.transform.MegaPhase.transformUnnamed$1(MegaPhase.scala:356)
[error] dotty.tools.dotc.transform.MegaPhase.transformTree(MegaPhase.scala:427)
[error] dotty.tools.dotc.transform.MegaPhase.transformNamed$1(MegaPhase.scala:255)
[error] dotty.tools.dotc.transform.MegaPhase.transformTree(MegaPhase.scala:425)
[error] dotty.tools.dotc.transform.MegaPhase.loop$1(MegaPhase.scala:438)
[error] dotty.tools.dotc.transform.MegaPhase.transformStats(MegaPhase.scala:438)
[error] dotty.tools.dotc.transform.MegaPhase.transformUnnamed$1(MegaPhase.scala:359)
[error] dotty.tools.dotc.transform.MegaPhase.transformTree(MegaPhase.scala:427)
[error] dotty.tools.dotc.transform.MegaPhase.transformNamed$1(MegaPhase.scala:255)
[error] dotty.tools.dotc.transform.MegaPhase.transformTree(MegaPhase.scala:425)
[error] dotty.tools.dotc.transform.MegaPhase.loop$1(MegaPhase.scala:438)
[error] dotty.tools.dotc.transform.MegaPhase.transformStats(MegaPhase.scala:438)
[error] dotty.tools.dotc.transform.MegaPhase.mapPackage$1(MegaPhase.scala:379)
[error] dotty.tools.dotc.transform.MegaPhase.transformUnnamed$1(MegaPhase.scala:382)
[error] dotty.tools.dotc.transform.MegaPhase.transformTree(MegaPhase.scala:427)
[error] dotty.tools.dotc.transform.MegaPhase.transformUnit(MegaPhase.scala:454)
[error] dotty.tools.dotc.transform.MegaPhase.run(MegaPhase.scala:466)
[error] dotty.tools.dotc.core.Phases$Phase.runOn$$anonfun$1(Phases.scala:324)
[error] scala.collection.immutable.List.map(List.scala:250)
[error] dotty.tools.dotc.core.Phases$Phase.runOn(Phases.scala:328)
[error] dotty.tools.dotc.Run.runPhases$1$$anonfun$1(Run.scala:247)
[error] scala.runtime.function.JProcedure1.apply(JProcedure1.java:15)
[error] scala.runtime.function.JProcedure1.apply(JProcedure1.java:10)
[error] scala.collection.ArrayOps$.foreach$extension(ArrayOps.scala:1321)
[error] dotty.tools.dotc.Run.runPhases$1(Run.scala:263)
[error] dotty.tools.dotc.Run.compileUnits$$anonfun$1(Run.scala:271)
[error] dotty.tools.dotc.Run.compileUnits$$anonfun$adapted$1(Run.scala:280)
[error] dotty.tools.dotc.util.Stats$.maybeMonitored(Stats.scala:67)
[error] dotty.tools.dotc.Run.compileUnits(Run.scala:280)
[error] dotty.tools.dotc.Run.compileSources(Run.scala:195)
[error] dotty.tools.dotc.Run.compile(Run.scala:179)
[error] dotty.tools.dotc.Driver.doCompile(Driver.scala:35)
[error] dotty.tools.xsbt.CompilerBridgeDriver.run(CompilerBridgeDriver.java:88)
[error] dotty.tools.xsbt.CompilerBridge.run(CompilerBridge.java:22)
[error] sbt.internal.inc.AnalyzingCompiler.compile(AnalyzingCompiler.scala:91)
[error] sbt.internal.inc.MixedAnalyzingCompiler.$anonfun$compile$7(MixedAnalyzingCompiler.scala:193)
[error] scala.runtime.java8.JFunction0$mcV$sp.apply(JFunction0$mcV$sp.java:23)
[error] sbt.internal.inc.MixedAnalyzingCompiler.timed(MixedAnalyzingCompiler.scala:248)
[error] sbt.internal.inc.MixedAnalyzingCompiler.$anonfun$compile$4(MixedAnalyzingCompiler.scala:183)
[error] sbt.internal.inc.MixedAnalyzingCompiler.$anonfun$compile$4$adapted(MixedAnalyzingCompiler.scala:163)
[error] sbt.internal.inc.JarUtils$.withPreviousJar(JarUtils.scala:239)
[error] sbt.internal.inc.MixedAnalyzingCompiler.compileScala$1(MixedAnalyzingCompiler.scala:163)
[error] sbt.internal.inc.MixedAnalyzingCompiler.compile(MixedAnalyzingCompiler.scala:211)
[error] sbt.internal.inc.IncrementalCompilerImpl.$anonfun$compileInternal$1(IncrementalCompilerImpl.scala:534)
[error] sbt.internal.inc.IncrementalCompilerImpl.$anonfun$compileInternal$1$adapted(IncrementalCompilerImpl.scala:534)
[error] sbt.internal.inc.Incremental$.$anonfun$apply$5(Incremental.scala:179)
[error] sbt.internal.inc.Incremental$.$anonfun$apply$5$adapted(Incremental.scala:177)
[error] sbt.internal.inc.Incremental$$anon$2.run(Incremental.scala:463)
[error] sbt.internal.inc.IncrementalCommon$CycleState.next(IncrementalCommon.scala:116)
[error] sbt.internal.inc.IncrementalCommon$$anon$1.next(IncrementalCommon.scala:56)
[error] sbt.internal.inc.IncrementalCommon$$anon$1.next(IncrementalCommon.scala:52)
[error] sbt.internal.inc.IncrementalCommon.cycle(IncrementalCommon.scala:263)
[error] sbt.internal.inc.Incremental$.$anonfun$incrementalCompile$8(Incremental.scala:418)
[error] sbt.internal.inc.Incremental$.withClassfileManager(Incremental.scala:505)
[error] sbt.internal.inc.Incremental$.incrementalCompile(Incremental.scala:405)
[error] sbt.internal.inc.Incremental$.apply(Incremental.scala:171)
[error] sbt.internal.inc.IncrementalCompilerImpl.compileInternal(IncrementalCompilerImpl.scala:534)
[error] sbt.internal.inc.IncrementalCompilerImpl.$anonfun$compileIncrementally$1(IncrementalCompilerImpl.scala:488)
[error] sbt.internal.inc.IncrementalCompilerImpl.handleCompilationError(IncrementalCompilerImpl.scala:332)
[error] sbt.internal.inc.IncrementalCompilerImpl.compileIncrementally(IncrementalCompilerImpl.scala:425)
[error] sbt.internal.inc.IncrementalCompilerImpl.compile(IncrementalCompilerImpl.scala:137)
[error] sbt.Defaults$.compileIncrementalTaskImpl(Defaults.scala:2363)
[error] sbt.Defaults$.$anonfun$compileIncrementalTask$2(Defaults.scala:2313)
[error] sbt.internal.server.BspCompileTask$.$anonfun$compute$1(BspCompileTask.scala:30)
[error] sbt.internal.io.Retry$.apply(Retry.scala:46)
[error] sbt.internal.io.Retry$.apply(Retry.scala:28)
[error] sbt.internal.io.Retry$.apply(Retry.scala:23)
[error] sbt.internal.server.BspCompileTask$.compute(BspCompileTask.scala:30)
[error] sbt.Defaults$.$anonfun$compileIncrementalTask$1(Defaults.scala:2311)
[error] scala.Function1.$anonfun$compose$1(Function1.scala:49)
[error] sbt.internal.util.$tilde$greater.$anonfun$$u2219$1(TypeFunctions.scala:62)
[error] sbt.std.Transform$$anon$4.work(Transform.scala:68)
[error] sbt.Execute.$anonfun$submit$2(Execute.scala:282)
[error] sbt.internal.util.ErrorHandling$.wideConvert(ErrorHandling.scala:23)
[error] sbt.Execute.work(Execute.scala:291)
[error] sbt.Execute.$anonfun$submit$1(Execute.scala:282)
[error] sbt.ConcurrentRestrictions$$anon$4.$anonfun$submitValid$1(ConcurrentRestrictions.scala:265)
[error] sbt.CompletionService$$anon$2.call(CompletionService.scala:64)
[error] java.base/java.util.concurrent.FutureTask.run(FutureTask.java:317)
[error] java.base/java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:577)
[error] java.base/java.util.concurrent.FutureTask.run(FutureTask.java:317)
[error] java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1144)
[error] java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:642)

So instead of trying to use primary constructor, I am trying to use another public one and I got this one.

wrong number of arguments at dropBreaks for (x$1: Unit): com.paulbutcher.test.JavaClassWithBridgeMethod: (com.paulbutcher.test.JavaClassWithBridgeMethod#<init> :
[error]    |  (x$1: Unit): com.paulbutcher.test.JavaClassWithBridgeMethod), expected: 1, found: 0

After it I am trying to pass there a () as argument and it gives me another error:

wrong number of arguments at pickler for (): com.paulbutcher.test.JavaClassWithBridgeMethod: (com.paulbutcher.test.JavaClassWithBridgeMethod#<init> :
[error]    |  (): com.paulbutcher.test.JavaClassWithBridgeMethod), expected: 0, found: 1
scala.MatchError: val <none> (of class dotty.tools.dotc.core.Symbols$NoSymbol$)

[nicolasstucki]

@goshacodes could you provide the implementation of the macro?

[goshacodes]

[goshacodes]

@nicolasstucki minimized example. Also I can try contribute this with a spree, want this fixed

build.sbt

lazy val root = (project in file("."))
  .settings(
    scalaVersion := "3.6.2",
    name := "java_class",
    scalacOptions ++= Seq(
      "-explain",
      "-Xcheck-macros"
    )
  )

JavaClass.java

public class JavaClass {
}

main.scala

import scala.annotation.experimental

@main
@experimental
def main(): Unit =
  mock[JavaClass]

Macro.scala

import scala.annotation.experimental
import scala.quoted.{Expr, Quotes, Type}

@experimental
inline def mock[T]: T = ${mockMacro[T]}

@experimental
def mockMacro[T: Type](using quotes: Quotes): Expr[T] =
  import quotes.reflect.*
  val tree = TypeTree.of[T]
  val parents =
    List(
      Select(
        New(TypeIdent(tree.tpe.typeSymbol)),
        tree.tpe.typeSymbol.primaryConstructor
      ).appliedToArgs(List('{()}.asTerm))
    )

  val sym = Symbol.newClass(
    Symbol.spliceOwner,
    "anon",
    parents.map {
      case term: Term => term.tpe
      case tpt: TypeTree => tpt.tpe
    },
    decls = _ => Nil,
    selfType = None
  )

  val cls = ClassDef(sym, parents, Nil)

  Block(
    List(cls),
    Typed(Apply(Select(New(TypeIdent(sym)), sym.primaryConstructor), Nil), TypeTree.of[T])
  ).asExprOf[T]

Output

[error] java.lang.AssertionError: assertion failed: private constructor JavaClass in class JavaClass in /Users/gosha/IdeaProjects/java_class/src/main/java/JavaClass.java accessed from constructor anon in class anon in /Users/gosha/IdeaProjects/java_class/src/main/scala/main.scala
[error] scala.runtime.Scala3RunTime$.assertFailed(Scala3RunTime.scala:8)
[error] dotty.tools.dotc.transform.ExpandPrivate.ensurePrivateAccessible(ExpandPrivate.scala:88)
[error] dotty.tools.dotc.transform.ExpandPrivate.transformSelect(ExpandPrivate.scala:98)
[error] dotty.tools.dotc.transform.ExpandPrivate.transformSelect(ExpandPrivate.scala:97)
[error] dotty.tools.dotc.transform.MegaPhase.goSelect(MegaPhase.scala:636)
[error] dotty.tools.dotc.transform.MegaPhase.transformNamed$1(MegaPhase.scala:245)
[error] dotty.tools.dotc.transform.MegaPhase.transformTree(MegaPhase.scala:452)
[error] dotty.tools.dotc.transform.MegaPhase.transformUnnamed$1(MegaPhase.scala:295)
[error] dotty.tools.dotc.transform.MegaPhase.transformTree(MegaPhase.scala:454)
[error] dotty.tools.dotc.transform.MegaPhase.loop$2(MegaPhase.scala:471)

[goshacodes]

@jchyb Also tagging you. Nicolas seems not active on github currently

[jchyb]

Yes, I recently took over some of Nicolas' responsibilities. Thank you for the minimization! I believe this might be getting fixed soon with #22104. I'll make sure it is in 3.6.4 (should be back portable to LTS).

[joan38]

Is this fixed in 3.6.4?
@goshacodes I'm using Scalamock with 3.6.4 but sounds like there is custom message before this blows?

[goshacodes]

Not sure if removing custom message would help even if it is fixed since scalamock is bound to 3.3.0 and Scala version is not updatable until experimental quotes api like Symbol.newClass and .info becomes stable.

Is this fixed in 3.6.4?
@goshacodes I'm using Scalamock with 3.6.4 but sounds like there is custom message before this blows?