On caring for user data: NeoVim caused Vim undo files to be deleted
- ID
- 29133
- Status
- summarized
- Published
- 27 Sep 2026, 10:45 PM
- Fetched
- 28 Sep 2026, 4:04 AM
- Provider
- Hacker News
- Category
- dev-community
- Original URL
- https://unsung.aresluna.org/they-had-no-concept-of-a-duty-of-care-to-their-users/
- Source URL
- https://hnrss.org/best
Summary
- Score
- 6.0
- Created
- 28 Sep 2026, 4:05 AM
- Tags
- Audience
- developersvibe_coders
What happened
On the Unsung blog, Marcin Wichary quotes a Mastodon post by computer scientist David Chisnall recounting that when he first tried NeoVim, it found his existing Vim persistent-undo file, deleted it (losing the history), and wrote its own incompatible format that Vim could not read. Chisnall says he filed an issue and was told the persistent-undo format was unstable and users should not rely on data being preserved in a feature named 'persistent undo'; Vim, by contrast, kept undo history across major version upgrades for roughly 20 years. The Hacker News thread drew 298 points and 260 comments.
Why it matters
If you switch editors or tool versions, check whether the old tool's on-disk state (undo history, caches, index files) gets migrated, renamed, or silently overwritten — Chisnall's case was data loss with no migration and no filename change. If you ship anything called 'persistent', 'durable', or 'saved', the naming is a promise; decide explicitly whether old formats get upgraded, kept alongside under a new name, or refused, and say so in the docs instead of in an issue thread after the data is gone.
Discussion angle
Where is the line between 'the format was never stable' and 'you deleted my data'? Ask the room: which features in your own product carry an implied durability promise, and what would a fork or a v2 do to users' existing files?