Ensure in PCG due to FPCGDataCollection having partially null data

Development World Creation
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1

We’ve seen some regular crashes in our game after upgrading to unreal 5.6 with PCG.

It appears like in this specific kind of graph set up in our game we’re reaching a point in PCG runtime execution where half of the inputs to the HiGenGridSize node contain null PCG data, which triggers an ensure in FPCGDataCollection::GetInputsAndCrcsByPin (ensure(TaggedData[I].Data)).

In our case the collection has 54 pieces of data, of which the first 26 are valid and the remaining entries contain null elements.

Is this a known issue that has already been resolved, or do you maybe have any pointers into what might cause null elements to appear in this case?

We have PCG multithreading turned off (pcg.GraphMultithreading=0), and it appears like none of the other threads are doing any work during the time of this crash.

2

Hi Ted, hope you’re well.

So a very long time ago we supported null data in the collections but we’ve moved away from this a while back, normally we either generate empty data or none at all in the collection.

Can you pinpoint what node is introducing the nulls in this case? It’s certainly not intended and we are not aware of a case like this.

We’ll be waiting for details!

Cheers,

Julien