Install problem on Mac: Suggestion

[jgclark]

(Edited)
I'm sorry this is probably really basic, but I couldn't get the first step of installation to work.
gem install solargraph gives errors:

ERROR:  Error installing solargraph:
	ERROR: Failed to build gem native extension.

    current directory: /Library/Ruby/Gems/2.6.0/gems/jaro_winkler-1.5.4/ext/jaro_winkler
/System/Library/Frameworks/Ruby.framework/Versions/2.6/usr/bin/ruby -I /System/Library/Frameworks/Ruby.framework/Versions/2.6/usr/lib/ruby/2.6.0 -r ./siteconf20191126-8244-132ryat.rb extconf.rb
mkmf.rb can't find header files for ruby at /System/Library/Frameworks/Ruby.framework/Versions/2.6/usr/lib/ruby/include/ruby.h

You might have to install separate package for the ruby development
environment, ruby-dev or ruby-devel for example.

More googling around and trying other things means I've now fixed it. But for the benefit of others, could you improve the documentation, adding that (for macOS) xcode-select --install is required? Then the slightly unhelpful error message shouldn't become a problem. Thanks.

[castwide]

Documenting this issue is a good idea. It isn't specific to Solargraph, but it comes up often enough to have a FAQ entry, at least.

Related: castwide/vscode-solargraph#78

[kirichkov]

Actually, after upgrading to Mojave, xcode-select --install didn't help. Apparently Apple stopped shipping (some of) the C header files for ruby, and split them in a separate package. To resolve this you'd also need to install them:

open /Library/Developer/CommandLineTools/Packages/macOS_SDK_headers_for_macOS_10.14.pkg

On Catalina I presume (not confirmed) you'd need:

open /Library/Developer/CommandLineTools/Packages/macOS_SDK_headers_for_macOS_10.15.pkg

[castwide]

Documented in the troubleshooting FAQ with brief instructions and a link back to GitHub.