Forwarded from Snownee/Cuisine#16.
We have received a crash-report that involves with this chunk of code from our mod, Cuisine:

ItemStack stack = inv.getStackInRowAndColumn(startX, startY);
FoodContainer container = stack.getCapability(CulinaryCapabilities.FOOD_CONTAINER, null);
if (container != null)
{
    CompositeFood food = container.get();
    if (food != null)
    {
        return !container.getEmptyContainer(stack).isEmpty();
    }
}
return false;

Notice that the getCapability call does not have a accompanied hasCapability call. This is clarified and considered as permissible since MinecraftForge/MinecraftForge#4978, which is available since Forge 14.23.4.2733. As such, the getCapability in CapabilityProviderFolder has problematic implementation:

@Nullable
@Override
public <T> T getCapability(@Nonnull Capability<T> capability, @Nullable EnumFacing facing)
{
    return FOLDER_CAP.cast(folder);
}

Specifically, it does not check if the capability token passed in is indeed the FOLDER_CAP. A example crash may be found in the forwarded issue ticket.
Considering the fact that the recommended Forge version is 14.23.5.2768 as of the time I am writing this, please consider adding a check against the capability instance (i.e. capability == FOLDER_CAP ? FOLDER_CAP.cast(folder) : null).