Re: [RFC 1/8] UTF helpers

Esko Luontola wrote:

[ long and incompatible plan removed ]

Generally when one wants to change one of the basic object types in git, some extraordinary benefit has to be shown that is not aimed at just a few people. Academic benefits (ie, "non-real-worldy") do not fall into that category. In fact, it's so rare for someone to provide such enormous benefit that the only time a core object format in git has been incompatibly changed is when Linus decided that trees should be able to have subtrees. The change reduced the repository size for the early git-tracked Linux kernel to about 4% of its original size, so there was a clear, undisputable and obvious benefit huge enough to warrant breaking the git repository format entirely just to get it in (I might have gotten those details entirely wrong, but it was something along those lines).

So unless you can change tree objects in a way that lets older git clients understand them while still adding this encoding cruft (it's cruft to me), I think your chances of getting such a change into the git core are about the size of the colour green.

If you're *really* serious about it though, here's how to go about it:

1. Make the changes so that newer git can always read and operate
on trees without the encoding information, regardless of what the
configuration says.
2. Modify 1.4.x branch to support this new format too, at least
for reading trees with the information in it. Otherwise some
package maintainers will just ignore such compatibility.
3. Modify 1.5.x branch similarly.
5. Make it configurable, but turned off by default and with a big
fat warning when its turned on.
6. 2 years later, remove the warning.
7. 2 years lter, turn it on by default.
8. 2 years later, remove the config option and make it a new
major release, but maintain the two codepaths forever.

1.[45].x branches are imaginary. They represent the branch that gets created when a new release in that series is necessary for some reason.

I haven't perused Robin's patches enough to know how they would interact with older git, and I'm not really interested in encoding issues. English being the lingua franca of internet and opensource development anyways, every project I've ever seen has only files named in a manner that would fit nicely into 7-bit ascii.