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Fri, May. 6th, 2005, 07:24 pm
More version control stuff

Linus Torvalds thinks that Git is already better at merging than everything else. In the sense that Linus personally has a magic merge algorithm knows as 'Andrew Morton' that's correct, but for everybody else this claim is completely false. (I asked around about what he could mean, and some people suggested that 'better' might have meant 'faster', which is the only explanation which doesn't involve Linus being delusional or lying.)

Unfortunately Linus's stated plans for Git are that it should only ever have whole tree three way merging (because that's the simple, practical, expedient way) and that it will have implicit renames and moves of lines between files (because that's the 'right' way). The resulting approach isn't workable even on paper. Whether the plans will be changed in advance of a disaster remains to be seen.

Meanwhile, we recently made a big advance in merge algorithms, you can read the latest about the upcoming new Codeville merge algorithm in this post.

Mon, May. 9th, 2005 01:38 pm (UTC)
ciphergoth: Re: diff

Doing it against the "mash-up" makes a lot of sense. Especially if you can tweak the "diff" algorithm to prefer matches using more-closely-related lines over less-closely-related if the length of the LCS is the same. That seems perfectly practical for the naive O(nm)-time dynamic programming "diff" algorithm I got taught at Uni; I don't know if it's just as easy for the more sophisticated algorithms used in practice.