• Have you followed the guidelines in our Contributing document?
• Have you checked to ensure there aren't other open Pull Requests for the same change?
• Have you added an explanation of what your changes do and why you'd like us to include them?
• Have you written new tests for your changes? Here's an example.
• Have you successfully run brew style with your changes locally?
• Have you successfully run brew typecheck with your changes locally?
• Have you successfully run brew tests with your changes locally?

Currently brew bump will output unable to get versions for the livecheck (or Repology) version if it's lower than the current package version. This makes it impossible to distinguish between a failing livecheck and one where the livecheck version is lower. We can detect when the package version is newer than the upstream version but bump doesn't do anything to handle the situation.

This addresses the issue by updating bump to display the lower upstream version and flag the current version with a trailing "(newer than upstream)" parenthetical to make the situation apparent (and so we can easily search for this text in the output). For example:

==> example
Current cask version:     1.2.4 (newer than upstream)
Latest livecheck version: 1.2.3

==> example
Current cask version:     arm:   1.2.4 (newer than upstream)
                          intel: 1.2.0
Latest livecheck version: arm:   1.2.3
                          intel: skipped

Besides that, I've set bump to skip duplicate PR checking if the current version is newer than upstream (or if both the current ARM/Intel versions are newer than upstream), as we only need to check for duplicate PRs if the upstream version is newer.

For what it's worth, I did brew bump runs across homebrew/core and homebrew/cask and didn't encounter any issues. That's not to say that this is definitively free of bugs but it's at least broader in scope than the manual testing I did while working on this.

The bump logic can be a little tricky to follow in places, so check my work and let me know if I've overlooked anything (especially conditional logic).