Just wanted to pop in and let people know that we take data corruption issues very seriously and try to fix any that we can (both in Blueprints and across the rest of the engine and editor any issues that cause loss of data are a high priority).
We’re not seeing much in the way of Blueprint data corruption across several internal games that make heavy use of Blueprints. I am very emphatically not saying there are no problems with Blueprint cyclic dependencies causing data loss, just that they are by no means universal or easy to reproduce. There were some issues with Robo Recall but some fixes were made and additional logging was added to try to track down any additional issues, but the issues didn’t reoccur. However, we’re working on a overhaul of how compilation of Blueprint dependencies happens (both at compile-on-load and interactive compiles where you press the Compile button), which results both in faster load times and a more robust, predictable compilation order. This work wasn’t ready in time for 4.16 but should be a part of 4.17 (it’s been on by default in the Dev-Framework branch for a few weeks now).
We think that the Blueprint Compilation Manager will help significantly with some of these hard-to-repro issues, but we can’t be certain without repro cases to verify against. At the very least it should make the testing environment more consistent.
@JoeW: I’m kind of grasping at straws, but you mentioned above that blowing away Saved and Intermediates made the problem temporarily go away, which should normally have no impact on anything that happens when loading the editor RE: content and BP compilation. Could you add ‘uses hot reload’ as an entry on the survey (something like never, rarely, sometimes, frequently, all the time)? That’s one variable that we don’t tend to use at all on our large internal projects.
Cheers,