They may or may not, it's a time-space trade-off, and I'm just guessing that they'll be more likely to go for eating disk over eating CPU. There's some details

They may or may not, it's a time-space trade-off, and I'm just guessing that they'll be more likely to go for eating disk over eating CPU. There's some details on this in https://git-scm.com/docs/hash-function-transition/#_fetch https://git-scm.com/docs/hash-function-transition/#_fetch; part of the expected hash transition document assumes that you could have say a SHA-1 *.pack, but maintain both a SHA-1 and SHA-256 index into its contents. For blob objects you could serve them up as-is, but for the other types which refer to other objects (commits, trees and tags) you'd either need to store two copies and do something close to a sendfile(), or rewrite them on-the-fly as you stream them, using your SHA-1<->SHA-256 translation table. So I got a bit ahead of myself there, but none of this interop code exists yet, so the trade-offs the forges will have to make are unknown at this point.