From what I'd read, SHA256 in git is showing every sign of being another IPv6. In particular:

- It's implemented in a non-backwards-compatible way

- The benefits over the older model are a bit nebulous

- There's a large amount of tooling that needs to catch up, and little sign that there is movement there

The difference with IPv6 adoption is that the internet relies heavily on network effects: so long as some hosts only have an IPv4 address, you need an IPv4 address for full connectivity, but then if everyone has an IPv4 address anyway, there is no immediate need to migrate to IPv6.

(Yes us Hacker News users have plenty of use cases for IPv6, like self-hosting and peer-to-peer networking and so on; we are not the average user.)

This effect doesn't exist for the Git migration. Each repo can be updated independently; it doesn't affect users of other repositories, and most likely, the majority of devs will work on some SHA-1 repos and some SHA-256 repos with no issue.

If anything, I would compare it with the Python 2 to Python 3 migration, which was also painful, but succeeded eventually (despite being much less necessary in the first place).

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kllrnohj 3 hours ago | parent | next [-]

> Yes us Hacker News users have plenty of use cases for IPv6, like self-hosting

Funnily enough, self hosting is why I can't use IPv6. I want vlan isolation, but only get a /64 from my ISP.

Fortunately the lack of IPv6 also isn't a meaningful loss anyway so whatever

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charlieyu1 3 hours ago | parent | prev | next [-]

I just started learning IPv6 with AWS since they charge $0.005/hr per IPv4. Maybe it will be more expensive in the future and eventually it will be the new default.

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metalliqaz 8 hours ago | parent | prev [-]

changing repos to the new IDs would break any existing links to content on the pre-migration repos.

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AndrewDucker 7 hours ago | parent [-]

Unless you link using tags.

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crote 6 hours ago | parent [-]

Which is considered a Really Bad Idea because tags aren't immutable, so there's absolutely zero guarantee that it'll point to the same commit a few months from now.

The GitHub Actions ecosystem found out the hard way, through some rather high-profile compromises. They hotfixed it by adding "immutable tags" to their platform, and are now working on adding a lockfile to... easily reference a commit hash.

	▲	PunchyHamster 3 hours ago \| parent [-]
		well if you use a knife to stab your fingers that's not a knife's fault repo can also rewrite existing commit and you again won't be able to retrieve it so switching to commit IDs only lowers the level of failure somewhat

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gspr 9 hours ago | parent | prev | next [-]

> - The benefits over the older model are a bit nebulous

This is far from the case with IPv6!

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post-it 9 hours ago | parent | next [-]

Is it? There are many benefits in principle to IPv6, but if my ISP continues to assign me a single dynamic IP, those benefits are entirely moot for me.

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bityard 9 hours ago | parent | next [-]

If your ISP is assigning you a single IPv6 address, they are doing IPv6 wrong. You should be getting your own /56.

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ghusto 8 hours ago | parent | next [-]

Every time you use the word "should" you're fighting reality.

	▲	bigstrat2003 2 hours ago \| parent \| next [-]
		If an ISP chooses to deploy a technology in a bad way, that is not the technology's fault. Even if most ISPs were just giving users a /128 address (which to be clear, is very much not the case), that would not be some kind of failure of IPv6.
	▲	gspr 6 hours ago \| parent \| prev [-]
		Plenty of ISPs do it right (examples: my last 3). That the parent poster's apparently doesn't isn't an argument against the technology their ISP fails to deploy correctly. Reality is that lots of ISPs do this right. And have for a very long time.

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bigstrat2003 9 hours ago | parent | prev [-]

Even a /64, while wrong, would be a significant improvement over IPv4.

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mort96 9 hours ago | parent | prev | next [-]

Your ISP assigns you a single dynamic /128? Which ISP is that?

	▲	post-it 7 hours ago \| parent [-]
		My ISP (Bell Aliant) doesn't support IPv6 at all. Rogers though, for example, assigns you a /56 block but it's dynamic.

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thenewnewguy 9 hours ago | parent | prev | next [-]

Is the argument that there are no benefits to IPv6 for anyone/society because your specific ISP messes it up?

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post-it 7 hours ago | parent [-]

Of course not. The argument is that the benefits are nebulous.

	▲	gspr 6 hours ago \| parent [-]
		... if you use ISPs that don't deploy the technology correctly. Faced with multiple providers of a technology, are we to judge its benefits by the worst ones?

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embedding-shape 9 hours ago | parent | prev [-]

Right, but just because you don't happen to have IPv6 right now, how does that remove the benefits for others to have IPv6? That's like saying having a faster CPU wouldn't mean faster performance, because I don't have that CPU yet.

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9 hours ago | parent | prev [-]

[deleted]

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Onavo 9 hours ago | parent | prev [-]

There's a massive push right now from top down to have secure software supply chains. Google SBOM and SigStore. It's not an organic need but if you have government customers you don't have many options.

	▲	Dayshine 9 hours ago \| parent [-]
		Ironically rewriting git history is a perfect opportunity for a supply chain attack.