[BUG] Diff panel hangs/whites out

Preflight Checklist

• [x] I have searched existing issues and this hasn't been reported yet
• [x] This is a single bug report (please file separate reports for different bugs)
• [x] I am using the latest version of Claude Code

What's Wrong?

Diff panel hangs/whites out when working tree contains single-line JSON >100 KB and/or modified binary >1 MB. Repro: stage a 500 KB single-line .json edit, click the +N −N chip.

What Should Happen?

The viewer should detect file-size or line-length and show a "too large to preview" placeholder instead of trying to render.

Error Messages/Logs

Steps to Reproduce

1. I click on the +# -# (next to the commit changes button). The side panel will open and go into a constant spinning circle, followed by a white screen.
2. I quit Claude Code Desktop, go back to that old session and the side panel is still open and in a constant spinning circle, followed by a white screen.
3. I have to quit Claude Code Desktop again. I can only start a new session.

Claude Model

Opus

Is this a regression?

I don't know

Last Working Version

_No response_

Claude Code Version

2.1.143 (Claude Code) in Claude for Mac Version 1.9255.2

Platform

Anthropic API

Operating System

macOS

Terminal/Shell

Terminal.app (macOS)

Additional Information

_No response_