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  1. Minecraft: Java Edition
  2. MC-130942

Errors, warnings and 10 second freeze on loading list of singleplayer worlds


    • Icon: Bug Bug
    • Resolution: Fixed
    • Minecraft 1.13-pre2
    • Minecraft 1.13-pre1
    • None
    • Unconfirmed

      When clicking "Singleplayer" in the main menu the game freezes for about 10 seconds and outputs various warnings and errors in the launcher log.

      I have various old worlds that were last opened in various old versions in the saves folders and it seems that it fails loading the level.dat of some of them.

      I don't think the level.dats of these worlds are corrupted though, because in 1.12.2 they load without any issues.

      It seems there are two outputs that might relate to the freeze/fail of loading the level.dats.
      14 times something like this:

      [00:28:38] [Client thread/WARN]: Unsupported key: CommandBlock in TaggedChoiceType[id, MobSpawner -> MuType[V143_4], 
      Chest -> ((Tag["Items", List[MuType[V143_3]]] | NilDrop), NilSave), 
      Airportal -> NilSave, 
      DLDetector -> NilSave, 
      Banner -> NilSave, 
      FlowerPot -> ((Tag["Item", (Int | NamedType["item_name", NamespacedString])] | NilDrop), NilSave), 
      Trap -> ((Tag["Items", List[MuType[V143_3]]] | NilDrop), NilSave), 
      EnchantTable -> NilSave, 
      Furnace -> ((Tag["Items", List[MuType[V143_3]]] | NilDrop), NilSave), 
      Dropper -> ((Tag["Items", List[MuType[V143_3]]] | NilDrop), NilSave), 
      Comparator -> NilSave, 
      Cauldron -> ((Tag["Items", List[MuType[V143_3]]] | NilDrop), NilSave), 
      Control -> NilSave, 
      EndGateway -> NilSave, 
      Music -> NilSave, 
      Piston -> NilSave, 
      Beacon -> NilSave, 
      Skull -> NilSave, 
      Hopper -> ((Tag["Items", List[MuType[V143_3]]] | NilDrop), NilSave), 
      Sign -> NilSave, 
      Structure -> NilSave, 
      EnderChest -> NilSave, 
      RecordPlayer -> ((Tag["RecordItem", MuType[V143_3]] | NilDrop), NilSave)]

      Likely relates to/overlaps with MC-130613.

      And 10 times something like this (it fails for level.dat as well as for level.dat_old, so it fails for five worlds):

      [00:28:39] [Client thread/ERROR]: Exception reading /home/panda/.minecraft/saves/Bunker_0.7/level.dat
      com.google.gson.JsonSyntaxException: com.google.gson.stream.MalformedJsonException: Use JsonReader.setLenient(true) to accept malformed JSON at line 1 column 3 path $
      	at com.google.gson.JsonParser.parse(JsonParser.java:65) ~[gson-2.8.0.jar:?]
      	at com.google.gson.JsonParser.parse(JsonParser.java:45) ~[gson-2.8.0.jar:?]
      	at cfa.<init>(SourceFile:108) ~[1.13-pre1.jar:?]
      	at cez.a(SourceFile:94) ~[1.13-pre1.jar:?]
      	at cez.c(SourceFile:76) ~[1.13-pre1.jar:?]
      	at cew.b(SourceFile:67) ~[1.13-pre1.jar:?]
      	at cph.g(SourceFile:35) ~[1.13-pre1.jar:?]
      	at cph.<init>(SourceFile:27) ~[1.13-pre1.jar:?]
      	at cpf.c(SourceFile:48) ~[1.13-pre1.jar:?]
      	at cmh.a(SourceFile:311) ~[1.13-pre1.jar:?]
      	at ciq.a(SourceFile:723) ~[1.13-pre1.jar:?]
      	at cmm$4.a(SourceFile:212) ~[1.13-pre1.jar:?]
      	at cjr.mouseClicked(SourceFile:103) ~[1.13-pre1.jar:?]
      	at ckn.mouseClicked(SourceFile:45) ~[1.13-pre1.jar:?]
      	at cmm.mouseClicked(SourceFile:352) ~[1.13-pre1.jar:?]
      	at cis.b(SourceFile:67) ~[1.13-pre1.jar:?]
      	at cmh.a(SourceFile:429) ~[1.13-pre1.jar:?]
      	at cis.a(SourceFile:67) ~[1.13-pre1.jar:?]
      	at org.lwjgl.glfw.GLFWMouseButtonCallbackI.callback(GLFWMouseButtonCallbackI.java:23) [lwjgl-glfw-3.1.2.jar:?]
      	at org.lwjgl.system.JNI.invokeV(Native Method) ~[lwjgl-3.1.2.jar:?]
      	at org.lwjgl.glfw.GLFW.glfwWaitEventsTimeout(GLFW.java:2599) [lwjgl-glfw-3.1.2.jar:?]
      	at cja.a(SourceFile:298) [1.13-pre1.jar:?]
      	at ciq.c(SourceFile:839) [1.13-pre1.jar:?]
      	at ciq.a(SourceFile:379) [1.13-pre1.jar:?]
      	at net.minecraft.client.main.Main.main(SourceFile:144) [1.13-pre1.jar:?]
      Caused by: com.google.gson.stream.MalformedJsonException: Use JsonReader.setLenient(true) to accept malformed JSON at line 1 column 3 path $
      	at com.google.gson.stream.JsonReader.syntaxError(JsonReader.java:1559) ~[gson-2.8.0.jar:?]
      	at com.google.gson.stream.JsonReader.checkLenient(JsonReader.java:1401) ~[gson-2.8.0.jar:?]
      	at com.google.gson.stream.JsonReader.doPeek(JsonReader.java:542) ~[gson-2.8.0.jar:?]
      	at com.google.gson.stream.JsonReader.peek(JsonReader.java:425) ~[gson-2.8.0.jar:?]
      	at com.google.gson.JsonParser.parse(JsonParser.java:60) ~[gson-2.8.0.jar:?]
      	... 24 more

            fry [Mojang] Georgii Gavrichev
            panda4994 [Mojang] Panda
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