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  1. Minecraft: Java Edition
  2. MC-54711

Quick pulses get lost in some repeater setups

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    Details

    • Type: Bug
    • Status: Open
    • Resolution: Unresolved
    • Affects Version/s: Minecraft 14w17a, Minecraft 14w18b, Minecraft 14w28b, Minecraft 1.8-pre2, Minecraft 1.8-pre3, Minecraft 1.8, Minecraft 1.8.1-pre3, Minecraft 1.8.1-pre4, Minecraft 1.8.1, Minecraft 1.8.2-pre4, Minecraft 1.8.7, Minecraft 15w31c, Minecraft 15w44a, Minecraft 15w45a, Minecraft 15w46a, Minecraft 15w47c, Minecraft 15w49a, Minecraft 1.8.9, Minecraft 15w50a, Minecraft 15w51b, Minecraft 16w02a, Minecraft 16w03a, Minecraft 16w04a, Minecraft 16w05b, Minecraft 16w06a, Minecraft 16w07a, Minecraft 16w07b, Minecraft 1.9 Pre-Release 1, Minecraft 1.9 Pre-Release 3, Minecraft 1.9 Pre-Release 4, Minecraft 1.9, Minecraft 1.9.1 Pre-Release 3, Minecraft 1.9.1, Minecraft 1.9.2, Minecraft 1.9.4, Minecraft 16w20a, Minecraft 1.10.2, Minecraft 16w32a, Minecraft 16w32b, Minecraft 16w33a, Minecraft 16w35a, Minecraft 16w36a, Minecraft 16w43a, Minecraft 1.11 Pre-Release 1, Minecraft 1.11, Minecraft 1.11.2, Minecraft 17w06a, Minecraft 1.12 Pre-Release 7, Minecraft 1.12, Minecraft 1.12.1 Pre-Release 1, Minecraft 1.12.1, Minecraft 1.12.2 Pre-Release 1, Minecraft 1.12.2, Minecraft 17w43a, Minecraft 17w43b, Minecraft 17w47b, Minecraft 18w19b, Minecraft 1.13-pre3, Minecraft 1.13-pre5, Minecraft 1.13-pre6, Minecraft 1.13-pre7, Minecraft 1.13-pre8, Minecraft 1.13, Minecraft 18w30a, Minecraft 1.13.2, Minecraft 19w03c, Minecraft 19w07a, Minecraft 19w12b, Minecraft 19w13b, Minecraft 1.14.4 Pre-Release 5, 19w37a, 1.15.2, 20w07a
    • Fix Version/s: None
    • Environment:
      Windows 7
    • Confirmation Status:
      Confirmed
    • Category:
      Redstone
    • Mojang Priority:
      Important

      Description

      When you send pulses into arrays of repeaters in quick succession, they will be lost. Let me explain what I mean with the picture.

      (Note: this description uses “redstone ticks”, which are actually 2 game ticks long.)

      On the left setup, when you press the button, a 1-tick off pulse will be generated. It will travel through ALL repeaters, but the last one. It does not matter how long the array of repeaters is, you could have 500 and the last one would fail to turn off. This might have to do with updates, but when working with complicated or fast timing circuits, this bug is very annoying.

      On the right setup, a 1 tick pulse is generated when you place a redstone torch on the redstone block. It should give a 1 tick pulse to the piston, then turn off for 1 tick, and then give another 1 tick pulse. Instead, it gives a single 3 tick pulse.
      This is the most annoying of all when you have a large (downward) piston extender which can only be powered from one side, because you have to use redstone lines and to BUD a piston below another one, you have to send 2 pulses with 1 tick of delay inbetween.

      Sorry for the long explanation/description.
      To test it you should build one of the below setups and try it out
      (Of course do this in one if the pre-1.8 snapshots)

      Code analysis

      Based on 1.11 decompiled using MCP 9.35 rc1

      The reason why the last repeater or comparator stays powered seems to be that the methods net.minecraft.block.BlockRedstoneDiode.updateState(World, BlockPos, IBlockState) and net.minecraft.block.BlockRedstoneComparator.updateState(World, BlockPos, IBlockState) set a different priority for the update based on whether or not a repeater or comparator is after them.

      Newer code analysis in this comment.

        Attachments

        1. 2014-05-06_18.12.12.png
          29 kB
          DicoTheRedstoner
        2. Pulsetest 1.png
          157 kB
          [Mod] Torabi
        3. Pulsetest 2.png
          173 kB
          [Mod] Torabi
        4. Rep-1.gif
          260 kB
          [Mod] Marcono1234
        5. Rep-2.gif
          296 kB
          [Mod] Marcono1234
        6. RepeaterBugWireFix.jpg
          551 kB
          CX gamer

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              • Assignee:
                Unassigned
                Reporter:
                dicotheredstoner DicoTheRedstoner
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                • Created:
                  Updated:
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