"Unknown buildpack type" error for default buildpack

[burnnat]

When specifying one of the default buildpacks to use for Heroku:

deploy:
  provider: heroku
  buildpack: ruby

Deployment fails with an error (see this build, for example):

Fetching buildpack... failed
Unknown buildpack type: https://github.com/heroku/heroku-buildpack-ruby

Looking at the anvil source, it looks like this error is reached when the buildpack URL has an unrecognized file extension. The URLs built by Travis for default buildpacks appear to have no extension (i.e. https://github.com/heroku/heroku-buildpack-ruby rather than https://github.com/heroku/heroku-buildpack-ruby.git). Perhaps they need to have a .git added?

As a workaround, one can supply the full URL (with extension) in .travis.yml and deployment will work:

deploy:
  provider: heroku
  buildpack: https://github.com/heroku/heroku-buildpack-ruby.git

[Aaron1011]

@burnnat: Sorry for the super long delay in getting to this.

[burnnat]

No worries, @Aaron1011 - since there's a simple workaround, I've been getting along just fine in the meantime. :)