MC-277314Nether portal linking appears to be broken
Steps to reproduce*
1. Open this world Pale Farten.zip
2. Go through the portal in front of you
3. Once you arrive in the nether go back through the portal you came from
4. You will spawn in a cave
5. Break the portal and tp back to the first portal /execute in minecraft:overworld run tp @s -34 65.00 -109
6. Repeat steps 2 & 3
Observed Results
- After doing steps 3 & 6 you will create a new portal in a cave instead of going back to the portal you first used.
Expected Results
- You would return to the portal you first entered instead of making a new one
Linked Issues
Created Issue:
Nether portal linking appears to be broken
Steps to reproduce
1. Open this world Pale Farten.zip
2. Go through the portal in front of you
3. Once you arrive in the nether go back through the portal you came from
4. You will spawn in a cave
5. Break the portal and tp back to the first portal /execute in minecraft:overworld run tp @s -34 65.00 -109
6. Repeat steps 2 & 3Observed Results
- After doing steps 3 & 6 you will create a new portal in a cave instead of going back to the portal you first used.
Expected Results
- You would return to the portal you first entered instead of making a new one
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![[Mod] Jarl-Penguin](../../../data/avatars/users/92849.png){kind=small}
duplicates
Steps to reproduce
1. Open this world Pale Farten.zip
2.Go through the portal in front of you
3.Once you arrive in the nether go back through the portal you came from
4.You will spawn in a cave
5.Breakthe portaland tp back to the first portal/execute in minecraft:overworld run tp @s -34 65.00 -109
6.Repeat steps 2 & 3Observed Results
After doing steps 3 & 6 you will create a new portal in a cave instead of going back to the portal you first used.Expected Results
- You would return to the portal you first entered instead of making a new one
Portals created between -128 to 128 (either X or Z or both) can fail to link both ways. Letting you from from overworld to the nether but not from the nether to overworld. This is because if the overworld portal is for example, on negative coords, the portal can be generated on positive coords in the nether. This new nether portal falls within the 16 block linking radious. But when going from nether to overworld these inverted coords get multiplied by 8 pushing the distance of the original overworld portal beyond 128 blocks and forcing a new portal to spawn.
Note: The below explanation is only considering 1 axis for simplicity. I'm assuming that to be the X axis. 2 values are given for nether portal position because nether portals must be at least 2 blocks wide.
- The furthest (from 0 in the overworld) portal that works both ways is located at +/- X126,125 with the nether portal located at +/- X1,0. If you enter the portal block at X0 you will be taken back. If you take the other side of the portal (X1) you'll be taken to a new overworld portal.
- On the other hand the closest (to 0 in the overworld) portal that's affected is at +/- X2, 1 with the nether portal being at +/- X16,15. Then if you take then X15 portal you'll be taken back to the same portal but the X16 portal block will spawn a new portal.
- Overworld portals created at values +/- X127,128 will always work only one way with a nether portal at +/- X1,0.
- Overworld portals at +/- 129 and beyond aren't affected by this bug because no valid inverted coord exists in the nether.
Note: The nether portal can be generated naturally and still be affected by this bug. But it's random so it's easier to build the portal yourself. An example of this bug happening naturally can be found in this world Pale Farten.zip
Steps to reproduce
1. Create a superflat world
2. Create a nether portal so that it's bottom obsidian blocks are located at XZ -84,0 and -83,0
3. Run command /execute in minecraft:the_nether run tp @s 5 60 -0 ~ ~
4. Create a nether portal so that its bottom obsidian blocks are located at XZ 6,0 and 5,0
5. Go through the portal block at XZ 5,0
6. You return to the portal you made in the overworld
7. Go back to the nether through the portal
8. Go through the portal block at XZ 6,0
9. A new portal is createdAlternatively use this world that's already setup: [^Repo world.zip]
1. Go through the overworld portal to the nether
2. Go through the portal block at XZ 5,0
3. You return to the portal you made in the overworld
4. Go back to the nether through the portal
5. Go through the portal block at XZ 6,0
6. A new portal is createdObserved Results
- In step 10 a new portal is created, despite the portal being previously linked with another overworld portal
Expected Results
- You would return to the portal you first entered instead of making a new one
Suggested Fix
- If the the overworld portal coords are between XZ -128 to 128 or the nether portal coords fall between XZ -16 to 16 on some axis, do the linking calculation with abs() values. Remember to only do abs() on the axis that falls in that range, because if you do both then you could for example have a portal in the nether at coords -100000, 8 link to an overworld portal at 800000, 64 which would be very bad.
Portals created between -128 to 128 (either X or Z or both) can fail to link both ways. Letting you from from overworld to the nether but not from the nether to overworld. This is because if the overworld portal is for example, on negative coords, the portal can be generated on positive coords in the nether. This new nether portal falls within the 16 block linking radious. But when going from nether to overworld these inverted coords get multiplied by 8 pushing the distance of the original overworld portal beyond 128 blocks and forcing a new portal to spawn.
Note: The below explanation is only considering 1 axis for simplicity. I'm assuming that to be the X axis. 2 values are given for nether portal position because nether portals must be at least 2 blocks wide.
- The furthest (from 0 in the overworld) portal that works both ways is located at +/- X126,125 with the nether portal located at +/- X1,0. If you enter the portal block at X0 you will be taken back. If you take the other side of the portal (X1) you'll be taken to a new overworld portal.
- On the other hand the closest (to 0 in the overworld) portal that's affected is at +/- X2, 1 with the nether portal being at +/- X16,15. Then if you take then X15 portal you'll be taken back to the same portal but the X16 portal block will spawn a new portal.
- Overworld portals created at values +/- X127,128 will always work only one way with a nether portal at +/- X1,0.
- Overworld portals at +/- 129 and beyond aren't affected by this bug because no valid inverted coord exists in the nether.
Note: The nether portal can be generated naturally and still be affected by this bug. But it's random so it's easier to build the portal yourself. An example of this bug happening naturally can be found in this world Pale Farten.zip
Steps to reproduce
1.Create a superflat world
2.Create a nether portal so that it's bottom obsidian blocks are located at XZ -84,0 and -83,0
3.Run command/execute in minecraft:the_nether run tp @s 5 60 -0 ~ ~
4.Create a netherportalso that its bottom obsidian blocks are located at XZ 6,0 and 5,05. Go through the portal block at XZ 5,0
6. You return to the portal you made in the overworld
7. Go back to the nether through the portal
8. Go through the portal block at XZ 6,0
9.A new portal is createdAlternatively use this world that's already setup: [^Repo world.zip]
1. Go through the overworld portal to the nether
2. Go through the portal block at XZ 5,0
3. You return to the portal you made in the overworld
4. Go back to the nether through the portal
5. Go through the portal block at XZ 6,0
6. A new portal is createdObserved Results
In step 10 a new portal is created, despite the portal being previously linked with another overworld portalExpected Results
- You would return to the portal you first entered instead of making a new one
Suggested Fix
- If the the overworld portal coords are between XZ -128 to 128 or the nether portal coords fall between XZ -16 to 16 on some axis, do the linking calculation with abs() values. Remember to only do abs() on the axis that falls in that range, because if you do both then you could for example have a portal in the nether at coords -100000, 8 link to an overworld portal at 800000, 64 which would be very bad.
Steps to reproduce*
1. Open this world Pale Farten.zip
2. Go through the portal in front of you
3. Once you arrive in the nether go back through the portal you came from
4. You will spawn in a cave
5. Break the portal and tp back to the first portal /execute in minecraft:overworld run tp @s -34 65.00 -109
6. Repeat steps 2 & 3Observed Results
- After doing steps 3 & 6 you will create a new portal in a cave instead of going back to the portal you first used.
Expected Results
- You would return to the portal you first entered instead of making a new one
Repo world.zip
Can confirm:
Would
MC-1403orMC-103502describe your issue? If not, is this issue specifically new to the latest snapshot?I'd say it's more likely a duplicate of
MC-149705