Redo buffer is cleared when saving a file

[Cre8or]

Summary

When undoing a change in a file and saving, the undone changes can no longer be redone. This is extremely frustrating because in addition to the UI not behaving as expected ("why is the redo history gone?!"), the file is saved in the process, so there is no way to retrieve the lost changes from disk either.

Description

An undo/redo system should always allow you to go back and forth between states, so long as you're not modifying the history in any way. Saving a file should act as a "modification" of the state. If undoing is possible after saving a file, then I also expect redo to work just aswell.

Steps to reproduce:

• Create a new file in Zed
• Write "hello world" into it (to add an undo level)
• Save the file ("hello world" has been written to the disk)
• Undo the modification from step 2
• Save again ("hello world" has been reverted, the file is empty)
• Try to redo the modification from step 2

Expected Behavior: "hello world" should reappear in the text editor
Actual Behavior: the file remains empty. My "hello world" is lost forever.

Screencast_20250511_150812.webm

Zed Version and System Specs

Zed 0.184.9

[AlfreddGco]

I thought this was just me doing something weird with the editor since I'm trying it out since a few days ago. Thanks for pointing this out. It is happening for me too (linux)

[gianpaj]

This is happening on macOS on Zed 0.186.9 as well

[notpeter]

Thanks for reporting.

This is caused by format_on_save pushing a new undo state which replaces the previous contents of the redo buffer. This does not happen if you "format_on_save": "off" or use the workspace: save without formatting action. You can easily see the same behavior by manually triggering format document, if this action triggers changes it removes the redo state(s) you've previously undone.

As a workaround, if you wish to be able to redo actions after save, you will need to disable format_on_save and trigger your own formatting manually (which will similarly replace your redo history, but at least you'll be in explicit control.

I'm not sure how this behavior could be different without supporting a different non-linear undo/redo history, so I'm going to close this as unactionable. If you have ideas for how such a non-linear undo/redo history could work, please open a discussion to flesh that out further. The current behavior enables users to "undo" any changes introduced by formatting, any solution would need to support synthetically rewriting the redo steps so they could be applied to the post-formatting document state, not the pre-format document state as they were originally constructed. Not impossible, but certainly non-trivial and I can't imagine how you could do it without conflict and unintuitive behavior (e.g. redo before format and redo after format are different operations if the changes overlap).

Thanks for reporting, but closing as unactionable.

[sammoore]

"format_on_save": "off" does not work for me, and I can't do what the other commenter suggested because I am in Vim mode using :w to save.

Is that a bug?

Unfortunately, I have no intent on switching what keyboard shortcut / motion I use to save, as this is a workflow with every editor I use, including the non-Vim ones. But anything that remaps :w would be a satisfactory workaround as well.

[joshuambg]

• Solutions for Undo/Redo Buffer Loss on Format-on-Save #31307

[bravecrayon]

FWIW I am experiencing this issue with "format_on_save": "off". However, workspace: save without formatting doesn't cause the issue.

Remapping cmd-s to "workspace::SaveWithoutFormat" has solved the issue for me for now.

[porsager]

Thank you so much!! the cmd-s solution was a lifesaver.. getting hurt by this issue daily has been tough...

[notpeter]

I've added a feature request for this.
Please 👍 upvote and subscribe to track progress.

• Support redo after autoformat changes buffer #31984

[quinncomendant]

I just lost a day's work because of this. 😖 Definitely unexpected behavior. I can't help it if muscle memory makes me accidentally hit ⌘S while reviewing changes by browsing the undo stack. 😂

[sammoore]

Yeah, this was a workflow I use heavily for going back to commit part of the work in a file. Was definitely unexpected.

In case you didn't see, above: #31021 (comment)