Summary:

Fix the default revision for existing/deleted files when parsing DiffX.

Review Request #11770 — Created Aug. 3, 2021 and submitted Aug. 3, 2021, 9:11 p.m.

Information
Owner:	chipx86
Repository:	Review Board
Branch:	release-4.0.x
Bugs:
Depends On:
Reviewers
Groups:	reviewboard
People:

Description

An issue was also found where deleted files in a DiffX were getting a
default revision of PRE_CREATION, which caused the deleted file to
show up as new. This should have only occurred for newly-created files.

Now, missing revisions show up as UNKNOWN, making it more clear that
the revision is missing, and avoiding accidentally triggering this bad
state.

Testing Done

Unit tests pass on Python 2 and 3.

Tested this in production and verified that it fixed an issue with a
file appearing as new when it should have appeared as deleted.

Commits

Summary
	Fix the default revision for existing/deleted files when parsing DiffX.

Screenshots

Issues

Description	From	Last Updated

flake8 passed.

JSHint passed.

Ship it!

```
Ship It!
```

Status: Closed (submitted)

Change Summary:

Pushed to release-4.0.x (19de9c1)