Is Rails 3.2.8 compatible with Ruby 1.9.3? - ruby

Question

I've been trying to follow the official rails guide and have run into an issue. There seems to be a syntax error message on code that was scaffolded in a new project using:
rails generate scaffold Post name:string title:string content:text.
Simple enough, right? I'm just going through the first page of the official rubyonrails.org "Make a blog" tutorial. But when I go to http://localhost:3000/posts I get this issue.
The SyntaxError Message:
/projects/blog/app/controllers/posts_controller.rb:9: syntax error, unexpected ':', expecting '}'
format.json { render json: #posts }
^
On step 6.3 I'm supposed to be seeing a simple "Listing posts" page, with presumably no blog entries.
My posts_controller.rb file:
class PostsController < ApplicationController
# GET /posts
# GET /posts.json
def index
#posts = Post.all
respond_to do |format|
format.html # index.html.erb
format.json { render json: #posts }
end
end
...(continued. This was all generated via a scaffold.)
My setup:
The guide says:
This Guide is based on Rails 3.2. Some of the code shown here will not work in earlier versions of Rails.
My rails -v says:
Rails 3.2.8
rubyonrails.org says:
We recommend Ruby 1.9.3 for use with Rails. Rails 3.2 is the last one that supports Ruby 1.8. Ruby 1.8.6 and earlier are not supported, neither is version 1.9.1.
My ruby -v says:
ruby 1.9.3p194 (2012-04-20 revision 35410) [x86_64-darwin12.2.0]
I always get that SyntaxError message, even after trying different versions of Ruby (using rbenv). Here are the versions I've tried:
1.9.2-p290
1.9.2-p320
1.9.3-p194 (latest)
Workaround:
Changing format.json { render json: #post } to format.json { render :json => #post } fixes the issue.
My Question:
Why, with the latest version of Ruby and the latest version of Rails, would I get a SyntaxError when the versions are supposed to be compatible? At this point in the first page of the official tutorial, I haven't even written any ruby. These lines in my posts_controller.rb file were generated by the latest stable version of Rails and the syntax is outdated? Rails hasn't been updated to use Ruby syntax going back to version 1.9.2?

Answer 1

In your Gemfile specify the ruby version like so ruby "1.9.3" right under the sources. See if that fixes it.
Edit I was having that problem deploying to heroku and adding that to my Gemfile fixed the error. Apparently it was trying to use 1.8.7 instead of 1.9.3 even though the ruby version specified by heroku was 1.9.3

Answer 2

mind putting this "puts RUBY_VERSION" at the top of your posts_controller? I'm curious if the right version is getting picked up. When you start the Rails server it should output the version number to the console.
Rails is definitely 1.9.3 friendly. 1.9.3 doesn't break anything that I'm aware of and since Rails is 1.8 compatible it should work moving forward just fine.