null-ls integration with undo functionality

[piersolenski]

null-ls has a way to format on save https://github.com/jose-elias-alvarez/null-ls.nvim/wiki/Formatting-on-save#code. However, when you try to undo the last change, it's undoing to the last formatted rather than the actual code content changing. This means you need to undo twice, and it can be a bit visually jumpy whilst it's trying to format you go through the changes. Neoformat used to handle this like so, https://github.com/sbdchd/neoformat#managing-undo-history - is there a way to do this with AutoSave? Thanks!

[piersolenski]

Solved here jose-elias-alvarez/null-ls.nvim#879