Heroku push rejected, no Cedar-supported app detec

Question

I'm creating a Rails app with Rails 3.1.3:

git init
git remote add heroku <my heroku repo>
git add .
git commit -a -m "First commit"
git push heroku master

Got:

Counting objects: 102, done.
Delta compression using up to 4 threads.
Compressing objects: 100% (86/86), done.
Writing objects: 100% (102/102), 315.47 KiB, done.
Total 102 (delta 3), reused 0 (delta 0)

**-----> Heroku receiving push
 !     Heroku push rejected, no Cedar-supported app detected**

To [e-mail]:electric-dusk-3217.git
 ! [remote rejected] master -> master (pre-receive hook declined)
error: failed to push some refs to <my heroku rep>

Answer 1

I was following the RailsTutorial.org steps and this error showed up. None of the answers on this post worked. Then I saw this comment that led to this answer which was the only thing that worked for me so that might solve other people's problems with the tutorial as well.

Answer 2

Another cause: I was pushing master, while working on a non-master branch. My master branch didn't have requirements.txt.

I didn't want to push from master, but heroku only pays attention to the master branch. The solution was to push my local branch to heroku's master branch:

git push heroku local_branch:master

Answer 3

Another cause of this error for Rails apps: we had this deploy error occur when we hadn't removed a git merge conflict from our Gemfile.lock file.

Answer 4

When this problem appears with the project based on static files (only html, css and js) it is recommended to follow this guidlines: https://discussion.heroku.com/t/push-rejected-no-cedar-supported-app-detected/640/3

Answer 5

I ran into this error message, but my problem was that my rails app was not in the root directory of my git repo. After I moved the files into the root dir, everything worked.

Answer 6

Not associated with a new app, but... I ran into this same error message after installing a custom BUILDPACK on heroku and then forgetting about it. The next time I went to deploy to heroku I saw:

-----> Fetching custom git buildpack... done

 !     Push rejected, no Cedar-supported app detected

The fix was to check:

 heroku config

And, there, I found a Var called BUILDPACK_URL which I had to unset with:

heroku config:unset BUILDPACK_URL

... and voila!