Editor Restoration

[thecoolwinter]

Description

Implements editor restoration, helping ease the user experience for longer editing tasks spanning multiple files. Users expect opened tabs to retain the scroll position, cursors, and undo stack. To facilitate this, we receive a stream of state updates from the editor and save them to a SQLite DB. When a file is opened again, the state is restored from that DB.

Ideally this is transparent to the user. However, there is one very slight UX flaw that this doesn't address: highlighting. When a user restores an editor there can be a flash as the highlighter works to do syntax highlighting on the newly opened editor. Some potential future directions:

• The text storage object that outlives editors does retain color information, if we could avoid wiping that color information when an editor is loaded we could avoid that slight delay.
• To do that, we need to store that state with the storage object somehow. Either through a custom text attribute (could be finicky) or maybe by subclassing NSTextStorage and adding a flag.

Note

This includes a mechanism for sharing undo stacks for editors during a workspace's lifetime. As @austincondiff mentioned on discord, it should add a undo frame when a file is updated externally. This PR notably does not include that change. I'll be adding it in #2075

Related Issues

• closes ✨ Save and Restore Editor State #2057

Checklist

• I read and understood the contributing guide as well as the code of conduct
• The issues this PR addresses are related to each other
• My changes generate no new warnings
• My code builds and runs on my machine
• My changes are all related to the related issue above
• I documented my code

Screenshots

Screen.Recording.2025-07-07.at.11.34.26.AM.mov