Compare tool fails to show files after swapping Source and Destination branches

Issue Summary

When using the Compare feature, swapping the from/to branches causes the Diff tab to display There are no changes to display. even when there are files to display.

Steps to Reproduce

1. Navigate to the Compare section of a repository.
2. Select two branches.
3. Change to the Commits tab and then back to Diff.
4. Swap the Source and Destination by clicking the swap button.

A video showing how to reproduce this bug is attached to this issue.

Expected Results

The Diff section will display files from both branches after swapping the Source and Destination branches.

Actual Results

Instead of displaying the list of files contained in each branch, a message displaying There are no changes to display. is shown.

Workaround

Swap between the Commits and Diff tabs and the files will load as expected.