perfect merges always → digle ≡ (file redefined as) DAG of lines

[zen at freedbms.net (Zenaan Harkness)]

Putting â??mere patch management scriptsâ?? such as Git to shameâ?¦

So merging is the great VCS challenge, due to conflicts and more
importantly the uncertainty of which of a number of conflict
resolution strategies is required to resolve any particular merge
conflict.

>From the VCS point of view, redefining a from from a sequentce of
lines, to a directed graph of lines, allows for endless automated
merging, with preservation of the resultant graphs, for possible
presentation to a user at some future time for "conflict resolution".

This sounds simple, but that's really only because it's so intuitive,
yet has now been put into a logically coherent mathematical paper
with fancy names which apparently establishes â??a sound theory of
patchesâ?? - which is a very good thing indeed for VCS boffins.

And the reason that a digle,

  file => sequence of lines

  digle => directed graph of lines

, is particularly useful, is that for one, merges can be done
automatically even in the case of conflicts, and simplified
presentation of conflicts and conflict resolution UIs is possible -
witness the various diff (and merge) "heuristics" which are too often
spoken of in Git land - which heuristics although very welcome, and
entirely suprerior to the VCS's of yore, are by virtue of being
heuristics and not "closed set" type functions, are naggingly and
annoyingly unrobust, at least mathematically/ logically, which is
doubly nagging due to Git's content-addressed data model design
breakthrough - surely we can have it all?

Well yes grasshopper, that's where your intuition is right, yes you
can, in the world of Version Control Systemes, have it all:

Teh paper: http://arxiv.org/abs/1311.3903

Teh model: https://pijul.org/model/#why-care-about-patch-theory

Teh easy description: https://jneem.github.io/merging/
Easy, part 2: https://jneem.github.io/pijul/

A VCS being built on teh theory: https://pijul.org/

Coming soon to a "mere patch management script" near you :)