James Koon
Comments
This bug originated sometime during 1.9's snapshot phase (might have been 15w30-42 if memory serves). I'm not sure if any devs can look into changes back to that time, but whatever caused the initial bug has never been fixed, only the effects have been patched. I noted all of the ways this bug was 'patched' in a previous comment, but am going to repost/update it here to help hopefully clarify the logic behind some of the code, that way if someone reads through this trying to figure out what's causing the problem, it may help in peeling back all of the patching involved so they can make sense of it.
Incorrect Teleport Coordinates after Dimension Shift - This was the original culprit. Players would find themselves in the wrong location after dimension shift (800x100x800 in overworld would lead to 800x100x800 in the nether or end). Coordinates would be the same as the overworld vs the nether, which sometimes would lead to death (especially if you TPed into the void in the End, or Lava in Nether). This was later patched to where the game teleports you back into the portal/location after you originally should have been teleported there (effectively rubberbanding the player to the portal, to the previous dimension coordinates, then back to the portal).
Portal Looping - Since you were moved out of the portal, and then the previous patch moved you back in, you effectively broke the game logic that you couldn't teleport immediately after spawning in a portal block. Due to the client attempting to load three locations (proper location, overworld equivalent coordinates, then back to the proper location), this often caused client side lag, as well as server lag, which would often not let the player move from the portal before they teleported again. The only way to break this looping was to kill the game. This was later patched with what I believe was a dimension shift cooldown.Incorrect Teleport Coordinates after Dimension Shift After Game Crash - If the game was killed during teleport, players would often find themselves spawned at the overworld equivalent location in the nether or in the nether equivalent location to the overworld depending on what dimension they were in while the game crashed (or was forced shut down), since the game effectively believed them to be disconnected and didn't bother with the translation back to the portal frame. This bug is not as often seen since the Portal Looping has been resolved with a dimension shift cooldown, however, would still be possible if the game crashes for any reason during teleport (Please note though this was bandaid fix, it happens often STILL for some people if their game crashes or they are DCed for any reason during dimension shift, especially if they are playing with a weaker PC).
Portal Damage (Suffocation & Fire) - Corresponding with the rubberbanding effect of being moved in and out of the portal frame during dimension translation, if any of the corresponding blocks were solid (suffocation) or lava (fire), you would take the appropriate damage. Since players are invulnerable during teleport now (as of 1.10 Pre-4?), they will not take the suffocation damage, but may still catch on fire, which can lead to additional damage once you leave the dimension shift sequence.
Ultimately, I've been watching this bug for a couple years now, as I admin a server and am often having to go remove lava blocks from server members portals. If there are any questions about this please feel free to contact me, but as I said, it originated in the 1.9 Snapshots, the effects of the bug have been patched instead of the bug itself, which in all honesty has probably made it more difficult to fix, especially as time goes on.
Glad someone actually looked into this... hopefully someone at Mojang can fix this, I'm tired of policing nether portals on my server. 😃
Why is this postponed? Shouldn't it be Reopened and assigned so it can be fixed sometime this year? This bug is very annoying and is persisting through the 1.10 snapshots.
Due to latency? Had one of the people on my server disconnect during dimension shift numerous times because he was playing at 2-3 bars. He was disconnected from the server, he didn't disconnect himself. Don't know if it'd work if you alt-F4'd during dimension shift or not to recreate or force-crashed your client?
This video was originally made for MC-89928 for Pre-2, but it offers a side by side shot of what's happening.
https://youtu.be/n9hZgJDO9TA
I can make an updated version with 1.9.4 but I've been able to repeat this in current versions.
Also, if you, due to latency, disconnect from the server during dimension shift, you are likely to find yourself in the opposite dimensions coordinates when you log back on.
EG: You enter a portal in overworld at 1000, 70, 1000 in the overworld. You DC. You log in. Instead of being at 125, 70, 125, you find you're at 1000, 70, 1000 in the nether. And it's in a wall. And you suffocate to death. GG.
One other thing I noticed one day when my internet was acting up a little was that moving at all causes "Moved too Fast" errors, creating bad bad bad rubber banding, and simply jumping would kick you using the No Flying kick.
@Jeffry R. Fisher
There is no patch for this. The best you can do is go to the exact coordinates in the nether that the overworld portal is in (so if the portal is at 300 22 300 in the overworld, go to 300 22 300 in the nether), and remove all lava blocks from that location. Hopefully this will be fixed in a later version.
@Eddie Bingham Also, beyond what Fabian mentioned, the behavior you indicated is not a bug. If you want to resolve your issue, make new portals at the correct coordinates. Portals attempt to place in the nether at x/8 y z/8, and from the nether to overworld x*8 y z*8, as long as that place is not obstructed.
311 66 137 (Over) to Nether is 38 66 17. If this area is obstructed by netherrack or lava, it attempts to place you close to land.
25 98 34 (Nether) to Overworld is 200 98 272, which is only a couple blocks off from your reported 198 72 274. (98 is adjusted to land level)
If you want your overworld portal to connect to the 38 66 17, go there, dig it out or place a platform, build a new portal and light it. It will link properly.
The portal issue is the only one I've had time to test. I have yet to see a "Player Moved Too Fast" while testing however, and since it's still happening, and we don't know what's going on behind the scenes (as far as if they changed how it's reported), and since the same things are happening without the error, I'm skeptical as to the bug itself being fixed.
I'll be checking the other items as well. I'll add a new comment if I find anything (such as the ghost blocks with beacons).
Yes, however, I was able to correlate the amount of "moving too fast" errors to the amount of ghost blocks. I'll have to record with a console open to show this. I'm about to head to work, but the ghost block issue seems to happen everytime the server corrects the coordinates of the player while using instant mine.
@bob
I believe you've outlined quite well in the description everything else that I've noticed except for one thing I noticed: If using a Speed 2 Beacon + a Haste 2 beacon, there is a vast increase in ghost blocks due to corrections to coordinates while breaking blocks. I was clearing out a 10 x 7 x 100 long tunnel around a beacon and was constantly getting ghost blocks.
The main reason I know so much about the nether is I have been building the nether hub on my server, and have been having to poke around to fix all the issues in regards to portal issues.
I will admit, certain patches such as the cooldown on dimension shifts and invulnerability while shifting dimensions are good safeguards, especially if there is server lag involved. But you are correct, future versions can really get screwed if they make one minor change and then suddenly all of the patches unravel. At this point, if this specific bug is fixed, there's a bunch of technically unneeded code in the game as well. :/
Also, if I'm correct, this was the cause of MC-89928 and all bugs related to the Nether Portal since 15w40a, all of which effects have been patched, including, but not limited to:
Incorrect Teleport Coordinates after Dimension Shift - Players would find themselves in the wrong location after dimension shift. Coordinates would be the same as the overworld vs the nether, which sometimes would lead to death (especially if you TPed into the void in the End, or Lava in Nether). This was later patched to where the game teleports you back into the portal.
Portal Looping - Since anti-cheat moved you out of the portal, and then the patch moved you back in, you effectively broke the game logic that you couldn't teleport immediately after spawning in a portal block. Due to the client attempting to load three locations (proper location, overworld equivalent coordinates, then back to the proper location), this often caused client side lag, as well as server lag, which would not let the player move from the portal before they teleported again. The only way to break this looping was to kill the game. This was later patched with what I believe was a dimension shift cooldown.
Incorrect Teleport Coordinates after Dimension Shift After Game Crash - If the game was killed during teleport, players would often find themselves spawned at the overworld equivalent location in the nether or in the nether equivalent location to the overworld depending on what dimension they were in while the game crashed (or was forced shut down), since the game effectively believed them to be disconnected and didn't bother with the translation back to the portal frame. This bug is not as often seen since the Portal Looping has been resolved with a dimension shift cooldown, however, would still be possible if the game crashes for any reason during teleport.
Portal Damage (Suffocation & Fire) - If the anticheat moved you into the corresponding block in the nether as the overworld portal after dimension shift, and that corresponding block was solid (suffocation) or lava (fire), you would take the appropriate damage. Since players are invulnerable during teleport now (as of Pre-4), they will not take the suffocation damage, but may still catch on fire, which can lead to additional damage once you leave the dimension shift sequence.
Finally, a current effect of this bug,is that you load & generate chunks far out in the nether that would otherwise never be visited. For example:
If you are at 800 70 800 in the overworld, and make a nether portal, the game will teleport you to a portal near 100 70 100. However, anticheat moves you to 800 70 800 (the location of the portal block you came through in the other dimension). If lava happens to be in that location, you will catch fire before your finally teleported back into the proper nether portal frame at ~ 100 70 100. I had also observed in gamemode 3 that if a ghast was spawned, it would attempt to lock onto the teleporting player at the 800 70 800 range.
Not only does this increase server load, it also unnecessarily increases the size of the server save file.
Please ask if you have any additional questions about these points.
@Fang Zhang
This was actually created in relation to MC-89928, but relates to the anti-cheat kicking in and then teleporting the player. The teleport action is clearly visible.
While I agree with the opening a new ticket, the invulnerability does not negate all damage... if you catch fire in the portal, you'll continue to take damage.
Confirmed for Pre-Release 4.
Video showing this bug:
https://youtu.be/ANfvuxkLV58
@Early Reflections @Matthew Barnes
Even if it is temporary, you're still able to catch fire, which can lead to death after the invulnerability ends.
Either way, I'm pretty sure that they tweaked something with the anti-cheat in 15w40-15w41 era, and that tweak is the culprit here. If they disabled the anti-cheat system, it would probably be a bad thing for release, as modded clients would allow for crazy speeds and teleporting for non-opped players.
It seems as if they added invulnerability on dimension change in Pre4. This is a work around, and IMO just lazy & sloppy programming due to the following reasons:
1 - It will still generate chunks in the nether far from the origin of the map. For example: Teleporting at 4000 70 4000 in the overworld would load 500 70 500 in the nether without this bug. However, this bug effectively generates chunks that may never be visited in the nether, at 4000 70 4000.
2 - It increases server load. Using the previous example, the fact that when you teleport from 4000 70 4000 in the over world to 500 70 500 in the nether, the chunks at 4000 70 4000 as well as 500 70 500 must load in the nether due to this bug. One person doing this at a time isn't a big issue, but if you have numerous people going through the nether on a multiplayer server, it has the potential to increase overall load on the server quite significantly. If this is also happening in the end, it's even worse.
3 - You can still catch fire while invulnerable. You then proceed to take damage afterwards.
Here is the video I took of Single Player opened to LAN on Pre-4 (my server isn't updated yet). It shows clearly that you are still teleported to the overworld equivalent coordinates, due to the setup I used this time.
EDIT: I did additional testing by running a server. Each time you go through the portal, the console states "darthkoonstyle moved too quickly!"... assuming now that if the Anti-Cheat system were set to ignore dimension shifts, this bug might disappear entirely.
Updated the bug report with Pre-3, error is still occurring.
Ultimately, I do believe this bug is in fact being caused by the anti-cheat system saying you moved to fast. Subsequent bug fixes since 15w42a have only been bug fixing the effects of this bug, not the cause.
youtu.be/2GG7bk-Hnqo?a
Would love to be able to test this with a console open but alas I cannot at this time without running a server off of my computer... is "Player moved too fast" errors still occurring during nether transports?
Confirmed. Also, they tend to glitch-fly out of water if you are around 40-50 blocks away from the squid (pictures attached) Once you get closer, they exhibit the glitching up/down movement and barely move as described above.
Also seems to affect squid who are over magma blocks. This would make it directly a squid issue I do believe, as they are affected exactly the same by up or down movement?