Scalac version 2.12.8 throws exception in unicode directory

[mlekena]

When in a directory path /Users/theko/Documents/code snippets/scala/unicode_test/𝔘𝔫𝔦𝔠𝔬𝔡𝔢, notice the 𝔘𝔫𝔦𝔠𝔬𝔡𝔢, scalac fails with the below stacktrace when calling -help or attempting to compile helloworld scala source.

scalac -help
Exception in thread "main" java.lang.ExceptionInInitializerError
	at scala.tools.util.PathResolver$Environment$.scalaExtDirs(PathResolver.scala:77)
	at scala.tools.util.PathResolver$Defaults$.scalaExtDirs(PathResolver.scala:127)
	at scala.tools.nsc.settings.StandardScalaSettings.$init$(StandardScalaSettings.scala:31)
	at scala.tools.nsc.settings.MutableSettings.<init>(MutableSettings.scala:28)
	at scala.tools.nsc.Settings.<init>(Settings.scala:19)
	at scala.tools.nsc.Driver.process(Driver.scala:53)
	at scala.tools.nsc.Driver.main(Driver.scala:80)
	at scala.tools.nsc.Main.main(Main.scala)
Caused by: java.lang.IllegalArgumentException: Error decoding percent encoded characters
	at java.base/sun.net.www.ParseUtil.decode(ParseUtil.java:209)
	at java.base/jdk.internal.loader.FileURLMapper.getPath(FileURLMapper.java:64)
	at java.base/jdk.internal.loader.FileURLMapper.exists(FileURLMapper.java:73)
	at java.base/jdk.internal.loader.URLClassPath$JarLoader.getJarFile(URLClassPath.java:802)
	at java.base/jdk.internal.loader.URLClassPath$JarLoader.access$900(URLClassPath.java:692)
	at java.base/jdk.internal.loader.URLClassPath$JarLoader$1.run(URLClassPath.java:751)
	at java.base/jdk.internal.loader.URLClassPath$JarLoader$1.run(URLClassPath.java:744)
	at java.base/java.security.AccessController.doPrivileged(Native Method)
	at java.base/jdk.internal.loader.URLClassPath$JarLoader.ensureOpen(URLClassPath.java:743)
	at java.base/jdk.internal.loader.URLClassPath$JarLoader.<init>(URLClassPath.java:718)
	at java.base/jdk.internal.loader.URLClassPath$3.run(URLClassPath.java:486)
	at java.base/jdk.internal.loader.URLClassPath$3.run(URLClassPath.java:469)
	at java.base/java.security.AccessController.doPrivileged(Native Method)
	at java.base/jdk.internal.loader.URLClassPath.getLoader(URLClassPath.java:468)
	at java.base/jdk.internal.loader.URLClassPath.getLoader(URLClassPath.java:437)
	at java.base/jdk.internal.loader.URLClassPath.findResource(URLClassPath.java:280)
	at java.base/jdk.internal.loader.BuiltinClassLoader.findResourceOnClassPath(BuiltinClassLoader.java:479)
	at java.base/jdk.internal.loader.BuiltinClassLoader.findResource(BuiltinClassLoader.java:303)
	at java.base/java.lang.ClassLoader.getResource(ClassLoader.java:1393)
	at java.base/java.lang.ClassLoader.getSystemResource(ClassLoader.java:1658)
	at java.base/java.lang.ClassLoader.getSystemResourceAsStream(ClassLoader.java:1762)
	at java.base/java.lang.Class.getResourceAsStream(Class.java:2607)
	at scala.util.PropertiesTrait.scalaProps(Properties.scala:39)
	at scala.util.PropertiesTrait.scalaProps$(Properties.scala:37)
	at scala.tools.reflect.WrappedProperties$AccessControl$.scalaProps$lzycompute(WrappedProperties.scala:49)
	at scala.tools.reflect.WrappedProperties$AccessControl$.scalaProps(WrappedProperties.scala:49)
	at scala.util.PropertiesTrait.scalaPropOrNone(Properties.scala:71)
	at scala.util.PropertiesTrait.scalaPropOrNone$(Properties.scala:71)
	at scala.tools.reflect.WrappedProperties$AccessControl$.scalaPropOrNone(WrappedProperties.scala:49)
	at scala.util.PropertiesTrait.$init$(Properties.scala:83)
	at scala.tools.reflect.WrappedProperties$AccessControl$.<init>(WrappedProperties.scala:49)
	at scala.tools.reflect.WrappedProperties$AccessControl$.<clinit>(WrappedProperties.scala)
	... 8 more

Version details:
Scala compiler version 2.12.8 -- Copyright 2002-2018, LAMP/EPFL and Lightbend, Inc.
javac 10.0.1
Mac version 10.13.6 (17G5019)

To reproduce:
Create directory with folder named 𝔘𝔫𝔦𝔠𝔬𝔡𝔢 (copy this name)
cd into folder and then run scalac -help

[som-snytt]

Come to think of it, this now wins the award for shortest reproducer, with zero LOC.

[som-snytt]

A workaround is to specify -nobootcp to scalac and scala.

[som-snytt]

Actually, the part where it passes -classpath "" actually passes a classpath consisting of "", not an empty one.

https://github.com/scala/scala/blob/2.13.x/src/compiler/templates/tool-unix.tmpl#L202

So the reason the loader is touching the current dir is

$ scala -J-Dsun.misc.URLClassPath.debug=true hello.Main
Opening file:/Users/andrew/snips/%ed%a0%b5%ed%b4%98%ed%a0%b5%ed%b4%ab%ed%a0%b5%ed%b4%a6%ed%a0%b5%ed%b4%a0%ed%a0%b5%ed%b4%ac%ed%a0%b5%ed%b4%a1%ed%a0%b5%ed%b4%a2/%22%22

Similarly,

$ ls \"\"/nocp
C$.class	C.class
nocp $ scala
Welcome to Scala 2.12.8 (OpenJDK 64-Bit Server VM, Java 11.0.2).
Type in expressions for evaluation. Or try :help.

scala> nocp.C(42)
res0: nocp.C = C(42)

or

$ scala scala.tools.util.PathResolver
object Environment {
  scalaHome          = /Users/andrew/scala-2.12.8 (useJavaClassPath = true)
  javaBootClassPath  = <429 chars>
  javaExtDirs        = 
  javaUserClassPath  = ""
  scalaExtDirs       = 
}

[som-snytt]

It seems that if the user does not specify a class path, the tool could be started with java -jar, and with -classpath otherwise. A quick test shows that to work. -usejavacp can be shown the door at last. -Xlint ought to warn if a local dir named util (for example) is probed by the class path.