Read-only buffer support

[heaths]

In #7128 the idea was brought up to have a read-only mode similar to vim. @the-mikedavis also mentioned Kakoune as an example that refuses to enter Insert mode, compared to vim that simply warns you you're trying to edit a read-only buffer. I can't find an existing discussion for this, so I wanted to start one here because I like to use vim often as a better pager e.g., curl https://domain.tld/json | jq | vim -R -.

Personally, I like vim's behavior that is warns I'm editing a read-only buffer and then let whether there's even a file path attached to the buffer or the file is protected decide whether I can save it. This lends itself well to other use e.g., certain user-writable buffers like help content could automatically be marked read-only but we could forcibly overwrite them if we have suitable permissions. I.e., don't make helix the gatekeeper for whether we can do something - only let us know it may not work.

[Deebster]

+1

My ideal for this feature would be that it allows you to edit (with a visible warning), but doesn't complain about the unsaved buffer. This would allow both saving (when desired) and minimal friction when using as a pager.

edit: So I guess "read-only buffer" is a misnomer. Ephemeral buffer? Volatile buffer? Transient buffer?

[eikenb]

edit: So I guess "read-only buffer" is a misnomer. Ephemeral buffer? Volatile buffer? Transient buffer?

I'd say this is more like a buffer for a read-only file. Could probably reuse the read-only-indicator for this as well.

[Guillawme]

I would also happily use helix in read-only mode as a pager. Its navigation commands would be great for this use-case.

[tastapod]

I think vi and vim get the terminology wrong here. Using vim -R or view opens the buffer in a write-protected mode that they call readonly.

You can do all the editing you like, but when you go to close the buffer, you have to use either w! or q!. In other words, you have to deliberately force-write or abandon any changes you made (or write them to a new buffer).

I feel like this would be trivial to implement in helix, given it already recognizes write-protected files when you open them. It would just be a per-buffer toggle.

• :set readonly true would match the [readonly] marker when you open a write-protected file.
• :set write-protect true would align better with other settings (there are several write settings, and nothing about read or readonly).
• :set save-protect true would match other save settings (e.g. auto-saving options).

That said, settings tend to be session-wide rather than buffer-specific, so maybe:

• :buffer-protect as a toggle to match e.g. buffer-close

Regardless, I would love to see this as a drop-in replacement for view.