syntax_tree gem uses triple dots Ruby >= 2.7 syntax for method parameters

[vittorius]

Hey all. I'm getting the following error when running the ruby-lsp extension in VS Code:

bundler: failed to load command: ruby-lsp (/Users/vittorius/.rbenv/versions/2.6.9/bin/ruby-lsp)
/Users/vittorius/.rbenv/versions/2.6.9/lib/ruby/gems/2.6.0/gems/syntax_tree-2.3.1/lib/syntax_tree.rb:9:in `require_relative': /Users/vittorius/.rbenv/versions/2.6.9/lib/ruby/gems/2.6.0/gems/syntax_tree-2.3.1/lib/syntax_tree/formatter.rb:12: syntax error, unexpected ... (SyntaxError)
    def initialize(source, ...)
                           ^~~

My project is Ruby 2.6.9.

This means that although ruby-lsp is able of choosing the right Ruby version via the version manager it is not able to support different Ruby versions by itself

[evilcins]

I am seeing the same thing - using jruby.

[vittorius]

I suggest at least stating the >= 2.7 requirement in the documentation (here on GitHub).

[vinistock]

This is similar to #1561. The gem has a requirement on Ruby 2.7 or higher indeed.

This is not well surfaced in the VS Code extension, we'll need to add a message to warn people that the server won't run on old rubies.

On jruby, you may hit other issues. We were trying to add it to our CI, but it seems that are a few inconsistencies in its Ripper implementation when compared to MRI, so you may get weird results.

[andyw8]

@vinistock we should maybe add a platform entry to the gemspec to prevent it being installed in a JRuby repo.

[vinistock]

Well, we do want it to work in jruby eventually. We just need to dive into the test failures in Shopify/vscode-ruby-lsp#549 and report them to the jruby team after we understand exactly what's different.