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  1. Minecraft: Java Edition
  2. MC-278259

Dimension padding behaves differently when set to the default value vs omitting

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    • Icon: Bug Bug
    • Resolution: Unresolved
    • None
    • 24w45a, 24w46a
    • None
    • Confirmed
    • (Unassigned)
    • Low
    • 1331054
    • Expansion B

      With the fix of MC-272062, the dimension_padding option in jigsaw structures behaves differently when set to 0 vs omitting the field. The 24w19a change-log specifies that dimension_padding is an optional field with a default value of 0.

      How to reproduce:

      1. Create a new world with the attached datapack
        • This datapack adds 2 structures, test:red and test:blue.
        • Both structures are projected to the OCEAN_FLOOR_WG heightmap and are set to generate in all end biomes
        • test:red has "dimension_padding": 0 set
        • test:blue doesn't specify a dimension_padding field
      2. Teleport to the end: /execute in minecraft:the_end run tp @s 2000 100 0
      3. Look around:
        • On end islands both red and blue structures generate
        • In areas with no end islands, only the blue structures generate

      Expected Result:
      I'd expect the structures to behave identically because the only difference is adding a field and setting it to the default value.

      Code analysis:

      This bug happens in the check for the start piece.
      net.minecraft.world.level.levelgen.structure.pools.JigsawPlacement.isStartTooCloseToWorldHeightLimits:

      if (dimensionPadding == DimensionPadding.ZERO) {
          return false;
      } else {
          \\...

      This disables dimension padding only when the pre-defined ZERO dimension padding object is used.

      • When the field isn't specified the ZERO is used as the default
      • When manually specifying 0 a new object with 0 padding is used, failing the check

      A fix would be replacing the == with a .equals call.

      Note:

      In case this different behavior for omitting the field is intended, I would like to point out:

      • The dimension padding is always active for all jigsaw pieces other than the start piece.
      • The .optionalFieldOf CODEC method uses .equals when comparing a value with the default during encoding. This means that the data generator can never produce the dimension_padding field with the value of 0, since it would be omitted in this case. In other words: The encoding -> decoding possibly changes the behavior of the dimension padding when set to 0.

        1. dimension_padding_bug.mp4
          4.14 MB
          jacobsjo

            Unassigned Unassigned
            CC_fan jacobsjo
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              Created:
              Updated:
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