This buildback is always enabled, i.e. when it's added to an app, the app will always be detected by Heroku as a "multi Gemfile" app, even if it's not.
It will however have no effect if the
BUNDLE_GEMFILE environment variable is
Ideally, we would only enable it when
BUNDLE_GEMFILE is defined, but
environment variables are not available in
bin/detect (see this issue).
BUNDLE_GEMFILE is present, it makes creates the following symlinks :
Note: the symlinks are only created if the source and the target are not already linked together (in any direction).
Copy the snippet above into CLI.