Bundler error message "Revision master does not exist in the repository"

Question

When trying to install the gem "u2f" from the repo at "castle/ruby-u2f" I get an error message:

Fetching git://github.com/castle/ruby-u2f.git
fatal: Needed a single revision
Revision master does not exist in the repository git://github.com/castle/ruby-u2f.git. Maybe you misspelled it?

I cannot find any information about this error message. The text does not appear in any of the bundler source files, so I don't even know where to start debugging.

If anyone has any insight into the source and cause of this error, I'd love to know.

Answer 1

If you're trying to install a gem from a github source and got this, it may be because the repo changed its default branch from "master" to "main". Try adding branch: 'main' and see if it works.

Answer 2

Try pulling from the master branch