IBM's old PMR system was their front-end, and they used CMVC as the back-end until it got replaced [1]. The two combined did what you described, and was the earliest example I know of as a commercial offering of version control tightly bound to bug reports. Very satisfying to see this concept get more traction with git and various bug trackers. I wish a public open interchange standard would evolve so the different integration combinations wouldn't be so brittle, though.

[1] https://en.wikipedia.org/wiki/IBM_Configuration_Management_V...