A post on Vim persistent undo and duty of care to user data draws 337 comments

Sources: post, discussion
Summary: The thread stands at 378 points and 337 comments in today's fetch. The post is prompted by an early Neovim undo-format change that deleted Vim undo files rather than migrating or renaming them, and it argues about what a program owes a file it did not create. The post is dated 2026-08-28 and the format change it describes is years old, so this is not a current Neovim regression. Its central account is a Mastodon post the article quotes at length, which was not resolved to the original account, so that attribution is unverified and the named maintainer response is secondhand.
Comments: Commenters surface Vim's :earlier 7d time travel as the feature actually at stake, note that early Neovim was understood as Vim with breaking changes, and one Neovim user reports realising a past failed undo after an upgrade may have been this bug. A contested strand argues volunteer maintainers owe users nothing, with at least one commenter reversing position after registering that existing files on disk were mutated rather than merely unsupported.
Why it matters: The value here is the norm being argued over data a program inherits, rather than any live defect.