Throws and exception in the `git diff` panel

[chuckjaz]

STEPS

1. clone the quickstart seed: https://github.com/angular/quickstart
2. Make change to app.component.ts
3. Click icon in left gutter to see the git diff
4. Cursor in the before pane

[angular-automatic-lock-bot]

This issue has been automatically locked due to inactivity.
Please file a new issue if you are encountering a similar or related problem.

Read more about our automatic conversation locking policy.

_{This action has been performed automatically by a bot.}