“They had no concept of a duty of care to their users.”

A Mastodon post by computer scientist David Chisnall has a very Unsung opener:

I have used vim since around 2000. I have written five books, a PhD thesis, a few dozen papers and over 150 articles with it. At this point, my higher brain functions are not engaged at all when I use a bunch of common vim commands, they just happen. Documents I wrote with anything else have random :w in the middle.

Chisnall goes on to talk about one specific vim feature:

Persistent undo is one of my favourite features of vim. […]

I don’t often need the persistent undo. But on the few occasions when I have needed it, it’s been invaluable: ooops, I deleted something from this file, maybe last week and one reboot ago, what was it? Undo until I find it, copy it, paste it into the current version. Or, a bit more commonly: I had this working, then I tidied it up ready to commit, now it isn’t working, what did I do?

Vim has kept this working across major version upgrades over a period of about 20 years. I don’t even think about it, it’s just part of Raskin’s First Law: A program may not harm a user’s data or, through inaction, allow a user’s data to come to harm. If vim or the computer crash, or if I close a file and come back to it six months later, my undo history is still there.

NeoVim is a fork of vim (in news for other reasons):

So I tried NeoVim when it was quite new. Vim that you are familiar with, but better? Great!

The first thing I noticed in NeoVim was that undo didn’t work. I tried opening the file in vim and undo didn’t work there either.

Neovim had changed the format of the undo files. It hadn’t upgraded the old one. It hadn’t used a different name for its undo files. It had just noticed the existence of a vim undo file, deleted it (losing all of the data in it) and replaced it with one that vim couldn’t read.

I raised an issue about this and was told that the persistent undo format was unstable and users should not rely on data being preserved in a feature explicitly called persistent undo. It had changed once and would probably change again.

And that ended my experience with NeoVim. 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.

I liked this post (which I quoted almost in its entirety), because it covers a few important things:

• I have never heard of the persistent undo like that, and it seems kind of amazing.
• People do remember when software loses their hard work or disrespects them.
• I can see how “It had changed once and would probably change again” can be such a powerful feeling.

I also loved it for the appearance of Raskin’s First Law. Jef Raskin, of Macintosh and Canon Cat fame, put together the three laws in his 2000 book The Humane Interface, and they go as follows:

• A computer shall not harm your work or, through inaction, allow your work to come to harm.
• A computer shall not waste your time or require you to do more work than is strictly necessary.
• An interface is humane if it is responsive to human needs and considerate of human frailties.

It was a very important and formative book for me to encounter as a young designer. I have no idea how these laws haven’t made it to Unsung before today.