git not able to detect any change when a heroku buildpack is setup

Question

I have built a rails app that I've deployed on Heroku. I was trying to use an API that relies on phantomjs, so I needed this package to be working on my Heroku server. I do this by:

heroku buildpacks:add https://github.com/stomita/heroku-buildpack-phantomjs

The buildpack gets added successfully to my app, and I get the following message:

Buildpack added. Next release on <myappname> will use:
  1. heroku/ruby
  2. https://github.com/stomita/heroku-buildpack-phantomjs
Run git push heroku master to create a new release using these buildpacks.

However, when I run git push heroku master, it says that everything is up to date, so I am somehow not able to create a new release using this buildpack. Would appreciate help on where I've misunderstood this concept and get phantomjs running on my app server on Heroku. Things I have already tried:

1. Logging onto my Heroku server and searching for a phantomjs binary. I couldn't find one and I guess it's because the binary is dumped only when an instance of the app is accessed
2. Restarting my app's heroku server by heroku restart
3. Searching SO, and someone with a similar problem says they had to do a 'recommit' but I don't think that is the issue here since git is not able to detect any change in the first place.

Answer 1

Git doesn't notice any changes because there aren't any changes to notice.

heroku buildpacks:add doesn't do anything to your local filesystem. It simply tells Heroku to add another buildpack when it builds your application. There's nothing new to push.

You can redeploy your existing code or add some meaningfull changes, create a new commit, and push that.