Unrecognized option: --add-exports

[GuillaumeDesforges]

Describe the bug

When Starting VSCode, I get

Java home: /nix/store/rjgb7sb2wrhl98gqda31h1iaa7v6nm9y-openjdk-11.0.12+7/lib/openjdk
Metals version: 0.10.8
Unrecognized option: --add-exports java.base/sun.nio.ch=ALL-UNNAMED
Error: Could not create the Java Virtual Machine.
Error: A fatal exception has occurred. Program will exit.
Downloading Metals failed with the following:
Process exited with code 1

To Reproduce

• Create a simple Scala project
• Write to .jvmopts

  --add-exports java.base/sun.nio.ch=ALL-UNNAMED
  

Expected behavior

Language server should not crash. Indeed, sbt works fine from console for instance.

Installation:

• Operating system: Linux
• Editor: Visual Studio Code
• Metals version: v0.10.8

Additional context

I am providing OpenJDK and sbt from Nix.
I've tried providing metals from Nix as well, but it did not fix my issue.

[tgodzik]

Thanks for reporting!

Metals uses .jvmopts for starting the server by default and it seems JDK doesn't recognize the --add-exports option. If you remove it the server should start. You can also specify a separate javaHome to a JDK that recognizes the option.

[GuillaumeDesforges]

Thanks for your reply. After some investigation, I actually think that the extension does not support options in the .jvmopts written with a space.

With

--add-exports java.base/sun.nio.ch=ALL-UNNAMED

Looking at https://github.com/scalameta/metals-languageclient/blob/main/src/fetchMetals.ts#L26 I expect that java is called with the jvm opts, but using console.log I could see it parsed it "wrong",

console.log("javaOptions=" + JSON.stringify(javaOptions))

gave

javaOptions=["--add-exports java.base/sun.nio.ch=ALL-UNNAMED"]

however, child process spawn, unlike shell calls, wants args separated by a space to be given one by one, so it would need to be equal to

["--add-exports", "java.base/sun.nio.ch=ALL-UNNAMED"]

in the end, I solved the issue by writing in .jvmopts

--add-exports=java.base/sun.nio.ch=ALL-UNNAMED

[tgodzik]

We should fix the issue somewhere around here:
https://github.com/scalameta/metals-languageclient/blob/main/src/getJavaOptions.ts#L32