Sinatra - undefined method `join' for #<String> - after removing Gemfile.lock

Question

I tried to update the Ruby version of a Sinatra website I am working on to 2.1.3. When I tried to bundle I had some errors. Then I removed the Gemfile.lock and bundle install proceeded. But when I ran the website I noticed some thing like

NoMethodError at /auth/login
undefined method `join' for #<String:0x000000062d3830>

My observations are as below.

• Downgraded to Ruby 2.1.2 - problem preserved
• Checked out the project as it was before (Ruby 2.1.2 with the old Gemfile.lock) worked
• The error showed up with a yield_content(:head) tag.
  • Removed all yield_content tags
  • Error showed up rendering the slim file for the page - slim :index, :layout => :layout, :locals => body_locals

What could be the error? I created a diff off the state of the Gemfile.lock before and after: https://gist.github.com/ziyan-junaideen/fb903abbdafdc2d4a02f

Error output from the terminal: https://gist.github.com/ziyan-junaideen/54bff4f05a5a7beeedff

I thought it was some SLIM error and downgraded Slim to 2.0.3 which used to be before the bundle install, but had no luck.

Any suggestion is highly appreciated.

Thanks

Answer 1

I have solved it by reinstalling slim and temple in versions slim: 2.0.3 and temple: 0.6.8, it's probably in temple, 'cos downgrading slim is not enough

Answer 2

I've got this error as well.

After some research I've found that it is happening because 'output buffer' for template rendering is an instance variable (its default name is @_out_buf), thus it is overwritten when each (sub)template rendering completes (because partials are being rendered in the same scope as main template)

There are a few ways to fix this without downgrading sinatra/slim/temple:

• Make default outvar value equals to _out_buf (local variable) @ lib/sinatra/base.rb#L814
• Pass an outvar option to slim method like this: == slim :sub_template, outvar: '_out_buf'

I've also opened an issue at sinatra's repo at github: https://github.com/sinatra/sinatra/issues/939 (let's see what authors will say about this)