We have 3 branches in TFS: Dev, Test and Production. We always promote in order - make changes in dev, promote to Test, and then promote to Prod after Testing has been approved. But I have run into an issue with a specific project. We've spent over a month rewriting the dev branch from the ground up so it has virtually nothing in common anymore with the other two branches. That was fine until yesterday when I was told I need to make immediate changes to the project to accommodate a third-party vendor's new API that will be released in 4 or 5 days whether we like it or not. The dev branch is only about 75% complete and untested, so we can't promote it yet, but we don't want to lose it either.
So how do I shelve the entire dev branch (for now) and bring the current Test branch back to Dev so we can temporarily work on it without losing all the progress we made on the new version?
Why not just create a new branch off of Test, do your vendor/API code in there, when done merge it to TEST, then merge TEST down to DEV.