NeoVim deleted a user's persistent undo history, and the response ended his trust
"They had no concept of a duty of care to their users."
Computer scientist David Chisnall used vim for over 20 years and relied on its persistent undo to recover work across crashes and months. When he tried early NeoVim, it silently deleted his vim undo files and replaced them with an incompatible format. The maintainers said the format was unstable and users shouldn't rely on data being preserved in a feature called persistent undo. Chisnall never used NeoVim again, invoking Raskin's First Law.
The authors showed immediately that they absolutely could not be trusted with any of my data. Breaking persistent undo is something I could forgive as a bug, but the attitude that just because something is a persistent file on your filesystem that contains data that you might want is no reason for their program not to delete it meant they had no concept of a duty of care to their users.
- jeremyjh
This story has no references that support the author's version of events, but it does appear to be substantially true that:
1. The change would break undo history, for both Neovim and Vim [see edit: this is not the really the case]
2. This means Neovim would delete data created by a different program, on another user's computer.
3. This was known before the feature was released.
4. They did it anyway.
I don't think there can really be any post-hoc justification of this.
https://github.com/neovim/neovim/pull/13973#issuecomment-789...
edit: I missed an important detail. The user specified the same path for undodir in both nvim and vim. Vim requires a path to enable the feature - there is no shared default path. The user sharing a path changes the story considerably in my view, because now this is a case of nvim deleting data created by nvim as an alternative to writing a data migration for it.
I could still disagree with that, but it makes alternatives like "just use a different path" more complicated at a minimum and really changes my read of this situation completely. I think Neovim's decisions are justfiable in this context. Maybe they could have saved the contents of the old undo folder somewhere and notified the user - arguably that would be more empathic I don't really agree they had a moral duty to do this.
- gavinhoward
As a Neovim user, this stopped me dead with painful realization: I may have suffered the same thing but didn't realize it. There was a time when I could not undo something, and it was after a Neovim upgrade.
Unlike Dr. Chisnall, I started my editor journey on Neovim, so it wasn't a transition that bit me. However, if the format of the persistent undo file is unstable, and Neovim just deletes it when it doesn't recognize the previous format, then it seems conceivable (to me) that an upgrade after changing the format would delete the file too.
Ouch. This is making me think about getting off of Neovim. Yes, FOSS comes as-is, but if there's an alternative...
- sdcfgy
I've used vim since the first time it appeared in Debian repos. I have been told a thousand times that NeoVim is better, more modern and solves many (conveniently never cited) issues. I just ignored it and carried on. Feeling terribly vindicated at this point as it's a feature I use regularly and have no idea that it would be an issue in NeoVim.
- BarbaryCoast
According to the rev history for VIM, persistent undo arrived in version 7.3, released in 2010. So Chisnall may have used it since 2000, but he didn't have persistent undo for at least two of the books he wrote. And it means it wasn't "maintained for almost 20 years", it's at best 16.
But it is a nice feature.
I do that by using version control. I have it hooked to my editor so that "save" is "check in". Now I have persistent, versioned, copies of all my states independent of whatever tools I happen to be using.
- gchamonlive
Am I missing something? Are people using persistent undo as backup?
This seems however more like of a documentation and UX problem. Neovim should warn and ask before deleting old undo files, or at least back them up, but it's not neovim's fault if people don't use reliable backup and versioning systems. Relying on persistent undo for this is kind of a self inflicted wound.
Use the proper tools for the job. Saying that neovim developers "had no concept of a duty of care to their users" is really disrespectful. Neovim's Lua API is overflowing with care, you just need to go look.
- natbennett
I was also a very early user of Neovim.
The way I personally remember it being positioned was “Vim, but with breaking changes.”
- dlisboa
> the attitude that just because something is a persistent file on your filesystem that contains data that you might want is no reason for their program not to delete it meant they had no concept of a duty of care to their users.
That's the wrong way to look at it. NeoVIM has a different concept of care for their users. They're optimizing for another kind of care, more in line with modern expectations, which VIM did not care about (hence the fork).
It's not better or worse, just different.
This same article could've been written about how VIM has no native LSP integration or autocomplete and they don't have duty or care for their users.
- skybrian
Software developers do sometimes make promises to their users, but I think these promises ought to be explicit rather than assumed. You can't simply assume a "duty of care" and expect that other people will understand them the same way you do.
(Or rather, you can, but you will likely be disappointed.)
- RVuRnvbM2e
Undo files and persistent undo are not meant to work that way. They are just persistent across process restarts. That's all.
They live in ~/.cache which is defined as "user-specific non-essential (cached) data".
Despite this user's impressive résumé, they simply misunderstood the feature.
- joelthelion
As a vim user, I feel neovim was useful for one thing: it shaked regular vim development a bit. That said, I see no reason to switch. Good old vim is rock solid and featureful. I hope it doesn't die due to neovim's competition.