`dist/bin/dotr` can't run with a custom `-classpath`

[nicolasstucki]

sbt dist-bootstrapped/pack
echo "object Main { def main(a: Array[String]): Unit = println(\"OK\") }" > Main.scala
./dist-bootstrapped/target/pack/bin/dotc -d out Main.scala
./dist-bootstrapped/target/pack/bin/dotr -classpath out Main

The last line will default to the repl instead running the application.

Note that dist-bootstrapped/target/pack/bin/dotr is generated from dist/bin/dotr when packing.

[rsoeldner]

I changed the dist/bin/dotr to

if [ -z "$1" ]; then
    echo "Starting dotty REPL..."
    eval "$PROG_HOME/bin/dotc -repl"
elif [[ ${first_arg} == "-classpath" ]]; then
    eval exec "\"$JAVACMD\"" "$DEBUG" "-classpath \"$CLASS_PATH\"" $@
else
    eval "$PROG_HOME/bin/dotc -repl $@"
fi

But If i run your example I receive:

./dist-bootstrapped/target/pack/bin/dotr -classpath out Main
Exception in thread "main" java.lang.NoClassDefFoundError: scala/Predef$
	at Main$.main(Main.scala:1)
	at Main.main(Main.scala)
Caused by: java.lang.ClassNotFoundException: scala.Predef$
	at java.net.URLClassLoader.findClass(URLClassLoader.java:381)
	at java.lang.ClassLoader.loadClass(ClassLoader.java:424)
	at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:335)
	at java.lang.ClassLoader.loadClass(ClassLoader.java:357)
	... 2 more

CLASS_PATH contains : :/home/rsoeldner/work/dotty/dist-bootstrapped/target/pack/lib/dotty-library_0.5-0.5.0-bin-SNAPSHOT.jar:/home/rsoeldner/work/dotty/dist-bootstrapped/target/pack/lib/scala-library-2.12.4.jar is this correct / what did i miss ?

[nicolasstucki]

@rsoeldner, that implies the JVM did not have the scala-library on the path.

If you change it to eval exec "\"$JAVACMD\"" "$DEBUG" "-classpath \"$CLASS_PATH\"" $@ you will see that you are going to execute

exec "/usr/bin/java"  -classpath ".:./dist-bootstrapped/target/pack/lib//dotty-library_0.5-0.5.0-bin-SNAPSHOT.jar:./dist-bootstrapped/target/pack/lib//scala-library-2.12.4.jar" -classpath out Main

where the second classpath overrides the value of the first one. Effectively running with only -classpath out.

We need to merge both classpaths into one and only emit that one. Executing something like this (note the place out):

exec "/usr/bin/java"  -classpath "out:.:./dist-bootstrapped/target/pack/lib//dotty-library_0.5-0.5.0-bin-SNAPSHOT.jar:./dist-bootstrapped/target/pack/lib//scala-library-2.12.4.jar" Main

We need to do something similar to the args as https://github.com/lampepfl/dotty/pull/3436/files#diff-215113124f1de02f228327ba7abb45f7R635 does but in bash.

On another note your issue makes me realize that we should also detect if the user defines several -classpath and print a warning. Not sure if we should join them all or take the last one as java does.

[nicolasstucki]

Also, the -classpath will not necessarily be the first argument.