Reviews created for the first commit in a branch do not show diff information if created during indexing

If a review is created for the first changeset that edits a file in a branch, no diff information is associated with the commit. This can cause issues when reviewing the file as it appears as an entirely new file.

Steps to Reproduce

1. Create a text file on trunk - Changeset 5
2. Modify this file on trunk - Changeset 6
3. Create a branch off trunk - Changeset 7
4. Edit the test file on the branch - Changeset 8
5. Edit the test file again on the branch - Changeset 9
6. While the initial indexing process is occurring, attempt to create a review for changeset 8
   

Expected Result

When creating the review for changeset 8, it will show the diff information between changeset 7 and 8.

Workaround

Wait for the full index to complete or use branch review as this issue has been fixed for it in CRUC-7190