How to suppress parser/current warnings?

[firedev]

When I run rubocop I get something like this on top:

warning: parser/current is loading parser/ruby21, which recognizes
warning: 2.1.6-compliant syntax, but you are running 2.1.2.

Is there a way to suppress that? It breaks Syntastic for Vim.

I can't change ruby version. There are other people working on this project and the version is locked.

[bbatsov]

You can't. It comes from the parser gem. /cc @whitequark

So many people have complained about this message that I'm starting to think it's more trouble that it's worth.

[firedev]

I think it would made sense if it was displayed with --verbose or --debug

[bbatsov]

As I said - it's not in RuboCop - we can suppress the output, but I don't want to do this, as we might end up suppressing something useful.

[whitequark]

2.1.2 and 2.1.6 genuinely differ in syntax.

If you want to complain to someone, complain to the Ruby MRI authors, who consider these changes between patchlevels acceptable.

I will not change parser.

[firedev]

Err... Okay. So how do I force Rubocop to not complaint about that?

[whitequark]

Run Rubocop as, for example, ruby -W0 -S rubocop args....

[bbatsov]

Keep in mind this will kill all the warnings, not just this one.

[firedev]

Thanks @whitequark I just deleted the warnings.

[ioquatix]

@whitequark if I can get some kind of unofficial guarantee that the Ruby core team won't break syntax in patch releases going forward, can we remove the warning?

[whitequark]

@ioquatix I'm not sure why you mean by "unofficial". If the Ruby core team publicly commits to not changing syntax in patch releases (which will doubtlessly benefit the entire ecosystem) I am of course fine with removing the warning, since there would be no reason to have it anymore.

[ioquatix]

@whitequark I don't know what's possible yet, and I don't know at what level we could make the guarantee, ideally it would never happen, but I need to investigate further, e.g. why it happened in the past. I guess I'm just looking at options to try and help mitigate the need for the warning.

[whitequark]

@ioquatix I think that is an excellent initiative and I look forward to your results.

[westonganger]

For anyone else coming here looking for an easy solution without updating their Ruby version. Just use the warning gem to suppress the output.

# config/initializers/warning_ignores.rb

### https://github.com/jeremyevans/ruby-warning

Warning.ignore(/warning: parser/)

[marcandre]

If I'm not mistaken, you should simply always use the latest parser gem and the latest Ruby. They are normally in sync.

[vizcay]

For anyone else coming here looking for an easy solution without updating their Ruby version. Just use the warning gem to suppress the output.

# config/initializers/warning_ignores.rb

### https://github.com/jeremyevans/ruby-warning

Warning.ignore(/warning: parser/)

@westonganger This allows to silence the warning starting rails server, etc. But not when just running rubocop.. or I'm missing something?