Is there any way to manually attach null-ls to the new unsaved buffer?

[RoRep1ay]

For example, I'm creating a new buffer with a JSON string in it, and I'm trying to format it, but couldn't because null-ls is not attached to it. So I'm wondering if there's a way to attach it manually...

(If I open a JSON file, I would get null-ls already attached to it and can do the formatting)

[jose-elias-alvarez]

You could theoretically get the null-ls client's ID and use vim.lsp.buf_attach_client() to attach manually, but I doubt it will work as expected. Also, a lot of sources will expect a file to exist on disk, so we'd have to do something like nvim-lspconfig's single file support, which would add a large maintenance burden.