Alex Bennée

According to https://help.minecraft.net/hc/en-us/articles/13803752803725 Chromebooks are now supported but I'm still unable to install it from the native play store. Should this bug be re-opened or a new bug created?

I've been playing around with the recent 1.18.2.03 build and doing a lot of underwater digging and so far nothing has tripped up. @Magdalena was there an explicit fix added to the build for this.

Falling in lava or digging under water (or in fact moving underwater) seem to be common themes to trigger the bug. While it could be mcpelauncher it might be just an x86'ism caused by something going through the funky x87 80bit floating point handling. It's hard to rule out mcplauncher because x86 builds of Minecraft are fairly rare due to the distinct lack of x86 android tablets/phones. I have a x86 Chromebook which has an Android runtime but for some reason Minecraft is blacklisted in the play store on it.

OK it's a race - you can issue a "tp PLAYER" on the server console after the player logs in and before the client crashes and that fixes it although you might need to restart the client. It's certainly faster than shutting everything down and exporting the map data to another machine to tweak and send back.

As to what causes it I'm still not sure. I thought maybe the input code may have passed a dud value into the minecraft code but so far my printf instrumentation hasn't found anything. If I find some spare time over the holidays I might try instrumenting the code via QEMU and see if I can identify where various NaN's appear. My simple hack of feenable(FE_INVALID) before calling the main code unfortunately triggers quite early on. It seems NaNs are pretty common.

@Randi: how do you teleport a player if they can't log in? AFAICT you can only act on players who have logged in.

I suspect MC-201406 is a duplicate although in that case they edited the world data with a remote 3rd party tool. In my case the data was caused by gameplay in the client and I could only restore access by using a 3rd party tool to fix the corrupted data.

I can confirm I've seen this bug. Whatever the mechanism that leads to the corruption of the remote data held on the server the player will not be able to join from any BedRock edition client thereafter (tested with Android x86/arm64 and PS4 clients). Generally the screen may start up with item bar and a blank void before eventually crashing the client. The only way to restore login is to manually edit the world data to a sane rotation value.

I suspect the best way to approach this is to defensively handle NaN values when first loading the player location and restoring a sane default when it's broken.