This story is about how I got some core gameplay working and decided it was time to slap a HUD on the game. I checked a few pages of documentation and proceeded to create my first HUD blueprint. Upon trying to open it, the editor crashed. That's pretty uncommon, so I restarted it and tried again, and it crashed again. That's really uncommon, so I restarted again, but I asked Google about it while UE4 was starting up. Turns out it's a known bug in the latest release. However, someone posted a workaround, which is to revert a specific commit from the repository.
I've never actually done that before, but a little bit of searching revealed that it was pretty easy. I didn't actually clone the whole UE4 project history, only the latest release, but I was able to get the patch for the commit by appending ".patch" to the github URL. (That is, it's https://github.com/EpicGames/UnrealEngine/commit/8fba9bbdc3cc4105d7c3de24adc94f7304c7d90b.patch, although you need to sign in and agree to Epic's terms to get source access; note that you can do this with any commit URL on github, which I did not know before.) I saved that to a file and reversed the commit via:
git apply -R
Couldn't be easier! Rebuilding the project via 'make' took just a minute or so, much less than the full build. Now, I can edit HUD widgets! I am still not good at it, but hey, we have to take this one step at a time.