Question

I’m trying to install Rails 3.1.

It says to use ‘gem install rails –pre’ in the announcement blog post here:

http://weblog.rubyonrails.org/2011/5/22/rails-3-1-release-candidate

When I try

$ gem install rails –pre

I get the error:

ERROR: While executing gem … (NameError)
uninitialized constant Syck::Syck

What to do?

Answer 1

Regarding your specific problem: You may be seeing an error introduced by a faulty build of Rails 3.0.8.rc3 that got pushed as “rails –pre”. See this issue in the Rails repository.

Instead of

gem install rails –pre

for the newest version, use

gem install rails -v “>=3.1.0rc”

or for 3.1.0.rc1 specifically:

gem install rails –version=3.1.0.rc1

See the guide referenced above for more advice.