Locomotive CMS app crashes after Heroku deploy - Couldn't load redcloth_scan

Question

I have an instance of Locomotive CMS running on Heroku and it has been running fine for about a year. I am the only developer so there have been no deployments since the last working deployment.

Yesterday I made an update to the config/environments/production.rb - all that I changed were the values for the existing ActionMailer settings. Committed and pushed, et voila - the app no longer functions.

The app works on the dev machine, when run in production and dev mode.

I'm a newb when it comes to Rails and Heroku, so I'm having some difficulty interpreting the log.

I've posted the log at: http://pastebin.com/GZpRaue6

The only clear error that I can see in the log is:

Couldn't load redcloth_scan

I have tried adding gem 'RedCloth' to my gems file and bundle installed, as it wasn't explicitly required in the original version of the source, but this has made no difference.

There is no mention of redcloth_scan in my gemfile.lock, but RedCloth is listed as a dependency of Locomotive.

locomotive_cms (2.0.0.rc9)
  RedCloth (~> 4.2.8)

Answer 1

After much messing about with the gemfile, each gemfile alteration simply causing different problems with loading the binaries for a different gem. So not an issue specific to redcloth.

I came across this SO post: What is the purpose of vendor/bundle? Heroku tells me to remove it

This use of --path is certainly not an elegant solution, my app never needed this before - something must have changed in Heroku and I'm hoping to be able to move away from this in future. But it's fixed it for now and that's good enough for me.