A Ruby App using
mimemagic is having difficulties building on Heroku.
There have been reports of build failures for Ruby apps using
mimemagic due to a recent yank of
mimemagic in relation to licensing.
This issue is outside of Heroku Platforms control, as
mimemagic is third party. However,
mimemagic has been updated and is now using an MIT license, and as such you will be able to use
mimemagic by updating the version to one using the new license. The easiest way to resolve this is to update Ruby itself to remove the dependency to
rails/activestorage and use Marcel instead.
Further information found in the following: