Reading a non-existent file on JS on Windows crashes

[jiribenes]

Confirmed repro:

import io
import io/error
import io/filesystem
import exception

def peek(filename: String): Option[Char] / Files = {
  val contents = do readFile(filename)
  if (contents.length == 0) None()
  else Some(contents.unsafeCharAt(0))
}

def run(filename: String) = {
  with default[IOError, String]{ "File not found" };
  with filesystem;
  peek(filename) match {
    case None() => "Empty file"
    case Some(c) => "The first letter is: " ++ show(c)
  }
}

def main() = println(run("ThisFileDoesNotExist"))

works on my machine (M1), printing File not found.
But on Windows, it seems to crash with:

Here's a trace of how I think this might have happened:

effekt/libraries/common/io/error.effekt

Line 455 in 898c86c

return errnoMap[-errno] || -1; // Default to -1 for unknown error names

effekt/libraries/common/io/error.effekt

Line 356 in 898c86c

case _ => panic("Not a valid error code: " ++ show(number))

[marzipankaiser]

Can reproduce on Windows/ARM in Parallels. However, coursier doesn't work there IIUC ( coursier/coursier#2175 ), so I don't really have a dev environment there... (in particular, no sbt)Just noticed: This is stdlib, so I could try and fix it.