Smalltalk-80 kept a history of edits called ChangeSets which could be filed out as diffs to be applied to other images. I wrote an application that allowed for the crafting of diffs for collaborative purpose as a late stage in a programming episode. This helped me think of programming as a continuous process without end.
I wrote a paper about this process and submitted it to an early OOPSLA. It got two reviews: recommend for award and hasn't this been done before? On the suspicion of the latter the paper was rejected.
I realized that I had written the paper as if it were a gift to a Smalltalk-80 user group. I hadn't bothered to identify what was new about the idea let alone defend that in terms of the literature.
Change sorting became key to community development of Squeak Smalltalk.
With pull requests now fundamental to workflow we see much more attention to Clean Git History.