New Source Control option: Revert To Status Branch

[Damon3000s]

A common situation we have been encountering is pull requests that include intended changes (accidental, not relevant to the PR, etc) and we request that they be reverted before being merged. The only way to ensure the files were removed from the PR is to ensure the uasset files were binary equal and to do that we needed to download the files from the status branch directly, replace them on disk and then commit the new (reverted) file. This was a cumbersome problem and sometimes a tad daunting for team members who were less comfortable browsing branches and downloading files.

The solution we came up with for this problem is to add a new context menu option that will revert the selected files to be a binary equal to what they are in the status branch. As you can see by the commit history this is something we tried to do on and off for a while (competing priorities) but finished and rolled out to the team at the end of August (~2 months ago from now).

Several important things to note about this change

• World assets (Maps) are excluded because the way UE handles reloading maps is problematic and we wanted to sidestep the issue as much as we can. Almost every other asset in UE can be reloaded and display the new version but maps don't and will continue to show the in-memory representation even if the file underneath has changed. This can lead to data loss if the in-memory file is saved again which will stomp the on-disk change. By not allowing Revert To Status Branch on World asset types we sidestep this potential issue.
• We initially hoped to make it so that if the Revert To Status Branch action failed that it would then run a regular Revert on all of the selected files but that was dropped after we encountered issues getting it working, and we determined it wasn't worth the additional time investment to get it working. In a way it is better to not perform additional actions after the first action failed so that the user has to figure out what went wrong etc. In our use cases we are only reverting one or two files at a time so it isn't a huge load, and errors are the edge case.
• We took the easy way out for the confirmation and used a simple "Are you sure" message box instead of trying to do something more complex like the Revert confirmation box which displays a list of selected files. This was a time saving measure.