PEP8 Style Checker passed.
Review Request #8886 - Created April 6, 2017 and submitted
If things go very wrong, a review request can end up in a half-created state. A dangling DiffSetHistory might be created, or a review request on a Local Site might not have a local ID. Chances of this are lessened with some of the diff parsing improvements that are going in, but it's still a possibility. We now take a more careful approach to creating a review request. Objects are created but not saved up-front. Once we know that everything is in a good state, we begin saving all the objects needed for the review request to the database. As a further improvement, we then also grab just the new local ID from the database, rather than the entire review request. This should prevent us from ending up in any more situations where users during high loads end up with broken review requests on Local Sites that just lead to further crashes.
Unit tests pass.
Tested manually with a breakage on a Local Site. Didn't end up with a
broken review request.