Comment by soraminazuki

That's some weird technicality that has nothing to do with the issue while also being completely false.

https://github.com/neovim/neovim/blob/fc3f0041fbe01c96f38224...

The feature that was broken is called persistent undo. The feature was inherited from Vim. In case it's not obvious from the name, nowhere does it state in the docs for persistent undo that data may be deleted at any time.

https://neovim.io/doc/user/undo/#persistent-undo

That Neovim changed the default storage path for undo files is completely irrelevant to whether the contract for persistence should be broken.