One of the features I hope we’ll see in the next generation of source control is having better support for annotating lines of source code with commit message i

One of the features I hope we’ll see in the next generation of source control is having better support for annotating lines of source code with commit message information. We have good old “blame” right now but it’s very easy to lose that information across refactors or reformatting (for example if someone introduces an auto formatter to the codebase, or if you move some code but also edit it such that your tool doesn’t understand the old code and the new code were related.) Commit messages are such a good place to explain code and I rarely need the same explanation in a comment. I worry though about the fragility of the connection between (a) the source code and (b) the important commits that explain why the code is there. Perhaps there are some very good UIs out there already that show something a little more intelligent than than the most recent commit from blame? Another idea might be to attach blame-like functionality to the syntax tree so that the explanatory messaging can be tracked at the function level, rather than as lines of source code. Can others here can point me in the right direction for either a more tangible description of this feature, or an existing research?