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?