[4.7] Editor Crashes While Copying Code from Another Function

Here’s what I remember: I made a new function in my base class and copied some code over from another func in the same base class. Then I think I decided it wasn’t what I needed after all, deleted it and compiled/saved. Crashed.

UE4.7.0-2397709+++depot+UE4-Releases+4.7

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Hi ,

Which nodes did you move/delete between the blueprints?

Here is an example copy/paste that will crash my project every time. I haven’t been able to repro this from a blank project yet. But if I copy these 3 nodes from one function to my main Event Graph and compile it crashes every time. Of course I have to connect the nodes (not shown in this image) to the graph before the compile. Granted all the arguments in this example aren’t properly wired up, and it won’t work in game, but it still shouldn’t crash while compiling.

Oh, it appears just copying the “Display Green Message” node is enough to cause the compile crash.

The display green message node is a custom function correct? What do you have inside of it?

Yes in my HUD, they are just defined as pass thru’s onto the UMG Widget inside it.

It should be giving an error saying the HUD argument isn’t properly assigned.

Unfortunately I’m not getting a reproduction on this error. Try updating to 4.7 preview 3 and see if this is still occurring.

This is in preview 3, I already updated this morning. I spent an hour or so trying to make a new project that crashes the same way, but no luck yet.

Ok, have you attempted to run the verification from the launcher? If that doesn’t work you may have to reinstall your editor.

Yes preview 3 verified. Copy/paste/compile that single node and it still crashes.

Ok, please try re-installing the editor. I will continue trying to reproduce this from my end and see if I can find any common link in your crashes. So far there is quite a bit of consistency but I don’t know what it is that is causing these crashes to occur.

Yes, still occurs after deleting all UE4 engines off my laptop and reinstalling.

Do you have a set of repro steps I can take that tend to reproduce this on your end? I have your project here (thank you for sending me this), so if you have some steps that consistently seem to crash the editor I’d be more than happy to try them on my end.

The copy/paste one for sure: Go into BP_BaseDeck function called Scanned and copy the “Display Green Message” node. Go into the event graph and at the end of the Event Tick chain of nodes, paste this single node. Connect the white execution wire to the end of the chain and press compile. It should crash immediately.

Another one: Go into BP_BaseDeck and find the function “Copy Movement Vars” find the input variable “from”, and change its type from BP_BaseDeck to BP_NewDeck and press compile

This one I reported isn’t a crash, but I don’t recall if you managed to recreate it: Go into BP_BaseDeck and find the function Busted. After the final node “Drop Download” extend a wire and add a “Cast To BP_Proxy” Don’t link anything to the Object pin. Now press compile and it says everything is fine, no warnings/errors. Press Play on the game and now it pops up saying there is a compile error. The message log at this point just says there is a compile error, but not specifically what it is. But switch back to the editor and press compile and it still says it compiles successfully in the Compiler Results tab.

Hi ,

I was able to reproduce this and have entered a bug report, UE-7694 to be assessed by the development staff. I am going to add your other crashes to the crash report as I believe they are all intertwined in some way (all producing the same exact error).

As a workaround for this, I found that there are two potential workarounds, try both and see if they work. The first is to copy/paste the cast node with the custom function (you should be casting when you do this anyways). The second would be to copy/paste the node in the event graph, compile, then hook up the exec pin and compile again. See if either of these help you out!

Another non-crash but broken behavior, this may be new to 4.7p3. The error links in the message log often don’t take you to the correct place in your code any more.

In BP_BaseDeck event graph, add the following intentionally bad code at the end of the OnComponentBeginOverlap chain. Run the game and bump your deck into a proxy without picking up a download so the cast fails and the Target Get Score node is executed with no target. The error message shows up in the message log properly, but if you click the Print String link here, it takes you to a different totally unrelated Print String node in an unrelated function.

Cool. If you didn’t notice I tacked on a different crash and a couple other non-crash bugs. You don’t need to bother coming up with work arounds just for me, I’ve usually long ago found my own by the time I got around to putting the trouble ticket in here. :slight_smile: