Description

When jj status shows a file is copied (prefixed by C), jjui fails to show a preview of the file.

Steps to Reproduce the Problem

1. Create an empty repo.
2. Commit one file with some text.
3. Copy the file, and make minor changes to both the new and original.

Expected Behavior

When viewing the copied file preview in jjui, you should see the changes between the original file and it's current state.

Actual Behavior

The preview window is empty.

Specifications

• Platform: Arch Linux
• Version: jj: 0.34.0, jjui: 0.9.5