NPE when invoking FindMe within range of a Steam Pump

[16:45:41] [Server thread/FATAL] [minecraft/MinecraftServer]: Error executing task java.util.concurrent.ExecutionException: java.lang.NullPointerException at java.util.concurrent.FutureTask.report(FutureTask.java:122) ~[?:1.8.0_181] at java.util.concurrent.FutureTask.get(FutureTask.java:192) ~[?:1.8.0_181] at net.minecraft.util.Util.func_181617_a(SourceFile:47) [h.class:?] at net.minecraft.server.MinecraftServer.func_71190_q(MinecraftServer.java:723) [MinecraftServer.class:?] at net.minecraft.server.MinecraftServer.func_71217_p(MinecraftServer.java:668) [MinecraftServer.class:?] at net.minecraft.server.integrated.IntegratedServer.func_71217_p(IntegratedServer.java:185) [chd.class:?] at net.minecraft.server.MinecraftServer.run(MinecraftServer.java:526) [MinecraftServer.class:?] at java.lang.Thread.run(Thread.java:748) [?:1.8.0_181] Caused by: java.lang.NullPointerException at com.buuz135.findme.network.PositionRequestMessage$Handler.lambda$onMessage$0(PositionRequestMessage.java:74) ~[PositionRequestMessage$Handler.class:?] at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511) ~[?:1.8.0_181] at java.util.concurrent.FutureTask.run(FutureTask.java:266) ~[?:1.8.0_181] at net.minecraft.util.Util.func_181617_a(SourceFile:46) ~[h.class:?] ... 5 more

Ok, so I don't understand why the GregBlockUtils SteamPump implements hasCapability and getCapability in such a way that hasCapability can return true but getCapability returns null.

https://github.com/EmosewaPixel/GregBlockUtilities/blob/1ff712391c580ecf9266f14cc94b1a1eab67eeed/src/main/java/gregblockutils/Machines/SteamPump.java#L136-L144

    @Override
    public boolean hasCapability(Capability<?> capability, EnumFacing side) {
        return (side == null || side.getAxis() != EnumFacing.Axis.Y) && super.hasCapability(capability, side);
    }

    @Override
    public <T> T getCapability(Capability<T> capability, EnumFacing side) {
        return (side == null || side.getAxis() == EnumFacing.Axis.Y) ? null : super.getCapability(capability, side);
    }

Consider what happens when something requests the ITEM_HANDLER_CAPABILITY for side null, as FindMe does. Since the SteamPump has an "inventory" of size 2, GregTechCE's MetaTileEntity happily reports that the SteamPump has the capability, but the SteamPump's getCapability will return null on account of the requested side being null.

This seems like the source of the behaviour I'm observing.

TheLimePixel / GregBlock

NPE when invoking FindMe within range of a Steam Pump #79