`scala` must not exit with 0 if the program threw an uncaught exception

[sevaseva]

Compiler version

3.1.0, 3.1.1, 3.1.2 as well as the tip of the main branch at the time of writing this.

On the other hand, this isn't affecting scala 2.13.4 (verified) and many/all other 2.x versions.

Minimized code

object Main {
    def main(args: Array[String]) = {
    	throw new RuntimeException()
   }
}

More concretely, in bash shell after building scala into scala3-3.2.0-RC1-bin-SNAPSHOT (with bin and lib in there):

scala3-3.2.0-RC1-bin-SNAPSHOT$ export SCALA_HOME=$(pwd)

scala3-3.2.0-RC1-bin-SNAPSHOT$ cat > a.scala << EOF
object Main {
    def main(args: Array[String]) = {
    	throw new RuntimeException()
   }
}
EOF

scala3-3.2.0-RC1-bin-SNAPSHOT$ cat a.scala
object Main {
    def main(args: Array[String]) = {
    	throw new RuntimeException()
   }
}

scala3-3.2.0-RC1-bin-SNAPSHOT$ bin/scalac a.scala

scala3-3.2.0-RC1-bin-SNAPSHOT$ bin/scala Main
java.lang.RuntimeException
	at Main$.main(a.scala:3)
	at Main.main(a.scala)
	at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:77)
	at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
	at java.base/java.lang.reflect.Method.invoke(Method.java:568)
	at dotty.tools.runner.RichClassLoader$.run$extension$$anonfun$1(ScalaClassLoader.scala:36)
	at dotty.tools.runner.ScalaClassLoader$.asContext(ScalaClassLoader.scala:80)
	at dotty.tools.runner.RichClassLoader$.dotty$tools$runner$RichClassLoader$$$asContext$extension(ScalaClassLoader.scala:18)
	at dotty.tools.runner.RichClassLoader$.run$extension(ScalaClassLoader.scala:36)
	at dotty.tools.runner.CommonRunner.run(ObjectRunner.scala:23)
	at dotty.tools.runner.CommonRunner.run$(ObjectRunner.scala:13)
	at dotty.tools.runner.ObjectRunner$.run(ObjectRunner.scala:48)
	at dotty.tools.runner.CommonRunner.runAndCatch(ObjectRunner.scala:30)
	at dotty.tools.runner.CommonRunner.runAndCatch$(ObjectRunner.scala:13)
	at dotty.tools.runner.ObjectRunner$.runAndCatch(ObjectRunner.scala:48)
	at dotty.tools.MainGenericRunner$.run$1(MainGenericRunner.scala:212)
	at dotty.tools.MainGenericRunner$.main(MainGenericRunner.scala:267)
	at dotty.tools.MainGenericRunner.main(MainGenericRunner.scala)

scala3-3.2.0-RC1-bin-SNAPSHOT$ echo $?
0

Output

That last output of 0 is the issue.

Expectation

The last command echo $? must print 1 or some other non-zero.
scala 2.13.4 does that.

[sevaseva]

After applying the one-line change https://github.com/lampepfl/dotty/compare/main...sevaseva:uncaught-exception-exit-1?expand=1 , scala does exit with 1 (and echo $? prints 1) as expected for the particular program mentioned in the issue. That's just a demo to help demonstrate the issue.

[som-snytt]

It would be a small nice thing to have a dedicated exception maybe in scala.runtime for now.