Support for Scala Metals

[modoodalvi]

Installing VS Code extension scalameta yields following error message on restart

[nolondil]

Additionally, it looks like the extension scala-lang is no longer able to apply syntax colour once Metals is running. Any new Scala file has no syntax colouring but metals is able to compile it (or Scala file that was not open yet before metals started).

[zetashift]

You have to install this plugin too: https://open-vsx.org/extension/scala-lang/scala to make it work correctly!
You'll still get an error but AFAIK it doesn't hamper functionality.

Also if anybody knows how to copy errors from the notifications pane I'd like to know!

[modoodalvi]

OK after installing the sclala plugin as suggested in the error message and by @zetashift , I get
This notification is sent quite often during manipulation of files.

I am not able to create Scala classes. Error messages are not shown correctly.

[bryphe]

Interesting, I tried the Scala + Scalametals plugin on a simple, 'hello-sbt' project, and didn't see those errors. It might be something special about the configuration of the project.

A couple of bits of info that might help, @modoodalvi

• Which platform is this? OSX, Linux, Windows?
• Is the project open-source - can I try building / opening it?

It's possible this error, like the one in #3311 (comment) - occurs in VSCode, but doesn't get surfaced like in Onivim.

I am not able to create Scala classes. Error messages are not shown correctly.

Do you have more details about this - when you say not able to create Scala classes, is it because of the issues with the error display?

This is a case where the output from the extension would be useful in troubleshooting (#2365)

[zetashift]

I'm on Linux, using a recent nightly version.
However even when I'm editing non-Scala files I get an error:

1. Here I'm just editing some Markdown files:
   
2. Here I am in a Nim project:
   

EDIT: just wanted to say, even with the notifications things still work from what I've tried.
EDIT2: From what I've tried a simple hello-sbt project doesn't notify me of an error either.

[bryphe]

Ah, thanks @zetashift ! I'm able to reproduce the error now, too - will help me figure out if it's a 'real' issue, or not.

I believe that, for some reason, this extension is getting activated inappropriately in this case - it shouldn't be running or activated at all in a nim project or a non-sbt project.

[modoodalvi]

Hi @bryphe, what is interesting: I created a really simple project to make the error message reproducible for you.
However, I don't see the error notification anymore ??? Here is the project setup I use: https://github.com/modoodalvi/scala-test.

[modoodalvi]

I can also confirm the error message when installing the Nim plugin.

[aldum]

Hi!

I'd like to provide (an) additional data (point):

• On Linux, using version 0.5.5

1. I have a very obviously c++ project, where metals activates:
   https://i.gyazo.com/2b1e4a888a7e750d889c018f5e323a59.png
   (also, the folder did not show up in the explorer after generation, I suspect that's addressed in Sidebar no refresh #3399)
2. "cannot read property 'includes' of undefined..." - only for Scala 3 projects, which makes sense, I suppose, because it should be handled by a different extension, which is not in openvsx, thus not easily installable in onivim
3. For Scala 2, this is not a problem, no error message. Completion looks like it's working.
   However, 'Create new Scala file' also doesn't seem to work for me, without any apparent error message.