Backup files

[00sapo]

Basically, the same as the backup option in (n)vim: every time a file is changed and then saved to disk, just save its previous version somewhere to keep a backup of the last edit.

This should be easy to implement, as it is basically a modified version of :update. With the variable expansion feature, this could also be set up by users autonomously, but I think it's better to provide a command ad-hoc for this, with a configuration automatic_backup and another backup_directory. If backup_directory is ".", then files are backed up side-to-side to the original files with the addition of ~ to the filename.

This is super-useful when while developing you delete files by mistake.

[EriKWDev]

When my battary died on windows and later bootet up, the file I had opened in helix was just blank when I opened it again.

I would love an option to just keep rolling backups of the open buffers as well somewhere. Or even auto save after a certain time :(

[the-mikedavis]

I wonder if we need to fsync(2) the file after writing here?

helix/helix-view/src/document.rs

Lines 931 to 933 in 00e9e5e

	let mut dst = tokio::fs::File::create(&write_path).await?;
	to_writer(&mut dst, encoding_with_bom_info, &text).await?;
	Ok(())

I'm not sure that <tokio::fs::File as tokio::io::AsyncWriteExt>::flush does file syncing and if we don't explicitly sync then the kernel may hold the changes in memory from what I understand. (Although fsync(2) is not always respected by the underlying storage anyways)

[EriKWDev]

I want to make a thing clear, the computer doesn't crash in the middle of a save/":w", the computer just crashes for different reasons and helix happens to have the file open.

This is when, later when I've rebooted, the file is suspiciously completely empty.

I don't know if this happens if I were to use other editors since I use nothing but helix, but it has happened so many times now.. wether it is just battery going out while helix is open or complete computer crash.

If you have any idea how I can help I will happily do testing

[the-mikedavis]

It's a bit of a shot in the dark but you can try the syncing suggestion with a small change locally, the-mikedavis@9eb1e59

fsync(2) is meant to flush the changes to a file to disk and it's typically used by databases (for example against a write-ahead-log file) to try to ensure that a write isn't lost during a power outage / hard shutdown. Without syncing a write might not actually update the disk, so even if the machine is crashing some time after a :w, the changes to the file might still only be in memory and could be lost.

[the-mikedavis]

Actually the Tokio docs talk about flush not synchronizing. I've posted #10735 with that patch to fix this (if that is the issue here)

[EriKWDev]

I'm very glad you're looking into this and if the fsync fix is what's needed I will definately give it a try going forward!

[oderwat]

I would like that it normally just saves regularly into a backup file while being open for desaster discovery. This could be versioned too. And I need he possibility to enable per language or better per project to save to the real files. This is because I sometimes want to have file watchers trigger rebuilds and hotloading and on other times I don't but still want to be able to recover my work. Having a watcher checking for changes in the buffer would be nice too. It should tell me if there are external changes, long before I would manual safe, because this could invalidate all the work I have done.

P.S.: As a workaround I currently snapshot my workspace using Kopia every 10 minutes.

[kirawi]

This is already addressed in #11374 (not yet merged) with editor.backup-kind = copy

For a file watcher see #1125

[oderwat]

I don't see that this is doing regular backups while working. It also seems not to have feature, that you for example get an initial copy and the have autosaves or that you get versioned copies while working. Something like this is done by the Jetbrains IDEs for example by implementing the file histories.

[kirawi]

Versioning should be the job of a VCS IMO. But #9154 will implement persistent sessions once I get around to finishing it though I guess it's not really what you're looking for? I'd suspect the maintainers would prefer such a feature of retaining copies of a file be delegated to plugins. I'm not aware of any other mainstream terminal editor that has such a feature built-in either.

[oderwat]

you do not want to store another version ever time you are idle with editing and saving a new version to the backup. I guess my "idea" about what could be done is not understood well. It is not a "version" it is like a persistend undo history, but simplified by storing diffs after editing parts of the text. You then can browser those. Jetbrains for example also stores checkpoints when you run formatters or external programms and also when it reloads changes like adding imports in the head of the files when auto imports are generated. I know it can works as they do that with all files in our huge projects. It is very powerful to have this even if you seldom use it.