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  1. Minecraft: Java Edition
  2. MC-120444

Almost any entity inside farmland gets teleported when it turns into dirt

    Details

    • Type: Bug
    • Status: Resolved
    • Resolution: Fixed
    • Affects Version/s: Minecraft 1.12, Minecraft 1.12.1 Pre-Release 1, Minecraft 1.12.1
    • Labels:
    • Confirmation Status:
      Confirmed

      Description

      The bug

      When an entity has its head inside farmland and the farmland turns into dirt, the entity will be instantly (in less than 1 game tick) teleported above the dirt.
      The teleportation works also with entities with NBT NoAI:1. They get teleported up too.

      How to reproduce

      [e.g. Floor is at y=10]
      1. Place a farmland 1 block above the floor. (e.g. x=10, y=12, z=20) [2017-08-28_11.41.47.png]
      2. Summon an armor stand on the floor with the head inside the farmland (e.g. x=10, y=11, z=20) [2017-08-28_11.42.23.png]
      3. Jump/place a block above the farmland to turn it into dirt. [2017-08-28_11.42.36.png]
      4. The armorstand instantly teleported up.

      Testing results

      • We can teleport an entity with farmland infinite times a tick, but due to the fact that entities can't go through more than a subchunk every gametick, the maximum (upwards) speed is 320m/s.
      • Farmland can be transformed by using pistons to move blocks above it, or by moving it below a block, and the bug still works.
      • It is possible to build a survival vanilla friendly 320m/s elevator (a subchunk per gametick), moving farmland below signs in the right order.
      • Items can be teleported by placing farmland above other farmand using the right update order (this also works at a subchunk per gametick).
      • Endermans (3 block high mob) gets teleported using a farmland every third block.

      Why it happens (my thoughts)

      I think it's a bugfix ended up badly: they tried to fix MC-104259 and they failed.

      By the way, it only works with farmland and not with path blocks.
      I made a video about to show the bug and to show the testing, HERE (turn on english subtitles).

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              • Assignee:
                grum [Mojang] Grum (Erik Broes)
                Reporter:
                Stypox Stypox
              • Votes:
                10 Vote for this issue
                Watchers:
                12 Start watching this issue

                Dates

                • Created:
                  Updated:
                  Resolved:
                  CHK: