scala/scala3

`java.sql.Driver` missing from classpath in macro in presentation compiler

kasiaMarek opened this issue · 1 comments

Original issue: scalameta/metals#6494

Compiler version

3.4.2

Minimized code

//> using scala "3.4.2"
//> using dep "com.h2database:h2:2.2.224"

import scala.quoted._

class LoadStuff extends Selectable:
  def selectDynamic(name: String): Any = name

object LoadStuff:
  transparent inline def make = ${ makeImpl }
   
  private def makeImpl(using Quotes): Expr[Any] =
    import quotes.reflect.*

    Class.forName("org.h2.Driver") // problematic line

    val refinement = Refinement(TypeRepr.of[LoadStuff], "name", TypeRepr.of[String])

    refinement.asType match
      case '[refined] => '{ LoadStuff().asInstanceOf[refined] }

Output

Interactive compiler reports error diagnostics:

java.lang.ClassNotFoundException: java.sql.Driver
        at java.base/java.net.URLClassLoader.findClass(URLClassLoader.java:445)
        at java.base/java.lang.ClassLoader.loadClass(ClassLoader.java:593)
        at java.base/java.lang.ClassLoader.loadClass(ClassLoader.java:526)
        at java.base/java.lang.Class.forName0(Native Method)
        at java.base/java.lang.Class.forName(Class.java:421)
        at java.base/java.lang.Class.forName(Class.java:412)
        at a.LoadStuff$.makeImpl(LoadStuff.scala:13)
        at a.LoadStuff$.inline$makeImpl(LoadStuff.scala:10)

Expectation

Should compile fine and diagnostics should be empty.

Hi,

Just adding some further info from the original issue.

Thinking about it, this can be further minimized, as this has nothing to do with Selectable. Apparently just being a transparent inline with class loading is enough to trigger this behavior:

object LoadStuff:
  transparent inline def make: Unit = ${ makeImpl }
   
  private def makeImpl(using Quotes): Expr[Unit] =
    Class.forName("org.h2.Driver")

    '{()}

This too triggers a loss of type-information at the call-site of make.

Removing transparent brings back type information.

Thanks