Bukkit

Is the problem reproducible ? If yes, please describe how
1. Just fly/walk in one direction in winter for ~10 seconds to load new chunks.
2.
3.

What's the problem ? What should be ?

There's two problems. First, the snow manager seems to overload on loading new chunks (and not many either). After it crashes, snow will keep falling, but no more will appear on the ground anywhere. And second, snow generates midair.

What version of Seasons,Craftbukkit, (ProtocolLib) do you use ?

All the latest.

Do you have an error log ? If yes, please provide it

2013-06-24 11:17:29 [INFO] Starting minecraft server version 1.5.2
2013-06-24 11:17:29 [INFO] Loading properties
2013-06-24 11:17:29 [INFO] Default game type: SURVIVAL
2013-06-24 11:17:29 [INFO] Generating keypair
2013-06-24 11:17:29 [INFO] Starting Minecraft server on *:25565
2013-06-24 11:17:29 [INFO] This server is running CraftBukkit version git-Bukkit-1.5.2-R1.0-b2788jnks (MC: 1.5.2) (Implementing API version 1.5.2-R1.0)
2013-06-24 11:17:29 [INFO] [AutoSaveing] Loading AutoSaveing v1.0.0
2013-06-24 11:17:29 [INFO] [LifeMC] Loading LifeMC v1.7
2013-06-24 11:17:29 [INFO] [ProtocolLib] Loading ProtocolLib v2.4.5
2013-06-24 11:17:29 [INFO] [ProtocolLib] Created default configuration.
2013-06-24 11:17:29 [INFO] [HungerPlusPlus] Loading HungerPlusPlus v0.4a
2013-06-24 11:17:29 [INFO] [Nordic] Loading Nordic v0.5.0
2013-06-24 11:17:29 [INFO] [Seasons] Loading Seasons v2.0.3
2013-06-24 11:17:29 [INFO] [ProtocolLib] Enabling ProtocolLib v2.4.5
2013-06-24 11:17:29 [INFO] [ProtocolLib] Started structure compiler thread.
2013-06-24 11:17:29 [INFO] [Nordic] Enabling Nordic v0.5.0
2013-06-24 11:17:29 [WARNING] **** SERVER IS RUNNING IN OFFLINE/INSECURE MODE!
2013-06-24 11:17:29 [WARNING] The server will make no attempt to authenticate usernames. Beware.
2013-06-24 11:17:29 [WARNING] While this makes the game possible to play without internet access, it also opens up the ability for hackers to connect with any username they choose.
2013-06-24 11:17:29 [WARNING] To change this, set "online-mode" to "true" in the server.properties file.
2013-06-24 11:17:30 [INFO] Preparing level "world"
2013-06-24 11:17:30 [INFO] Preparing start region for level 0 (Seed: 7984826904352820486)
2013-06-24 11:17:30 [INFO] Preparing start region for level 1 (Seed: 1356389217436542775)
2013-06-24 11:17:30 [INFO] Preparing start region for level 2 (Seed: 1356389217436542775)
2013-06-24 11:17:30 [INFO] [AutoSaveing] Enabling AutoSaveing v1.0.0
2013-06-24 11:17:30 [INFO] [LifeMC] Enabling LifeMC v1.7
2013-06-24 11:17:30 [SEVERE] [LifeMC] iConomy was not found! Disabling iConomy features!
2013-06-24 11:17:30 [INFO] [HungerPlusPlus] Enabling HungerPlusPlus v0.4a
2013-06-24 11:17:30 [INFO] [HungerPlusPlus] 0.4a enabled!
2013-06-24 11:17:30 [INFO] [Seasons] Enabling Seasons v2.0.3
2013-06-24 11:17:30 [INFO] [Seasons] Permission plugin not detected, defaulting to OP or in-built Permissions System.
2013-06-24 11:17:31 [INFO] [Seasons] Loaded 2 seasons for world.
2013-06-24 11:17:31 [INFO] [Seasons] Properties loaded for world , active : true
2013-06-24 11:17:31 [INFO] [Seasons] Save found for world
2013-06-24 11:17:31 [INFO] [Seasons] ProtocolLib has been detected and hooked.
2013-06-24 11:17:31 [INFO] [Seasons] Starting sending data to Metrics Servers each 10 minutes. To disable it, just set opt-out to true in PluginMetrics/config.yml
2013-06-24 11:17:31 [INFO] [Seasons] Seasons Plugin, by Rominos2, version 2.0.3, is enabled.
2013-06-24 11:17:31 [INFO] Server permissions file permissions.yml is empty, ignoring it
2013-06-24 11:17:31 [INFO] Done (1.100s)! For help, type "help" or "?"
2013-06-24 11:17:31 [INFO] CONSOLE: Forcing save..
2013-06-24 11:17:31 [INFO] CONSOLE: Save complete.
2013-06-24 11:17:31 [INFO] [ProtocolLib] The updater did not find an update, and nothing was downloaded.
2013-06-24 11:17:34 [INFO] /127.0.0.1:49305 lost connection
2013-06-24 11:17:36 [INFO] masterookoo[/127.0.0.1:49307] logged in with entity id 120 at ([world] -405.3858813033997, 61.0, -500.49057291297805)
2013-06-24 11:17:55 [INFO] masterookoo issued server command: /gamemode 1 masterookoo
2013-06-24 11:17:55 [INFO] masterookoo: Set own game mode to CREATIVE mode
2013-06-24 11:19:30 [INFO] Connection reset
2013-06-24 11:19:30 [INFO] masterookoo lost connection: disconnect.quitting
2013-06-24 11:19:32 [INFO] masterookoo[/127.0.0.1:49314] logged in with entity id 14082 at ([world] -386.38019794976873, 78.45383352705558, -34.67377468352066)
2013-06-24 11:20:55 [SEVERE] Exception in thread "Seasons-SnowThread"
2013-06-24 11:20:55 [SEVERE] java.util.ConcurrentModificationException
2013-06-24 11:20:55 [SEVERE]     at org.bukkit.craftbukkit.v1_5_R3.util.LongObjectHashMap$ValueIterator.next(LongObjectHashMap.java:299)
2013-06-24 11:20:55 [SEVERE]     at java.util.AbstractCollection.toArray(Unknown Source)
2013-06-24 11:20:55 [SEVERE]     at org.bukkit.craftbukkit.v1_5_R3.CraftWorld.getLoadedChunks(CraftWorld.java:131)
2013-06-24 11:20:55 [SEVERE]     at org.rominos2.Seasons.Managers.SnowManager.SeasonsSnowThread.run(SeasonsSnowThread.java:71)
2013-06-24 11:21:40 [INFO] masterookoo lost connection: disconnect.quitting
2013-06-24 11:21:40 [INFO] Connection reset
2013-06-24 11:21:44 [INFO] CONSOLE: Stopping the server..
2013-06-24 11:21:44 [INFO] Stopping server
2013-06-24 11:21:44 [INFO] [Seasons] Disabling Seasons v2.0.3
2013-06-24 11:21:44 [INFO] [Seasons] Seasons Plugin, by Rominos2, version 2.0.3, is disabled.
2013-06-24 11:21:44 [INFO] [Nordic] Disabling Nordic v0.5.0
2013-06-24 11:21:44 [INFO] [Nordic] Plugin was enabled successfully! You are using Reloaded version by kangarko.
2013-06-24 11:21:44 [INFO] [HungerPlusPlus] Disabling HungerPlusPlus v0.4a
2013-06-24 11:21:44 [INFO] [ProtocolLib] Disabling ProtocolLib v2.4.5
2013-06-24 11:21:44 [INFO] [LifeMC] Disabling LifeMC v1.7
2013-06-24 11:21:44 [INFO] [AutoSaveing] Disabling AutoSaveing v1.0.0
2013-06-24 11:21:44 [INFO] Saving players
2013-06-24 11:21:44 [WARNING] DSCT: socket closed
2013-06-24 11:21:44 [INFO] Saving worlds
2013-06-24 11:21:44 [INFO] Closing listening thread
2013-06-24 11:21:44 [INFO] Saving chunks for level 'world'/Overworld
2013-06-24 11:21:44 [INFO] Saving chunks for level 'world_nether'/Nether
2013-06-24 11:21:44 [INFO] Saving chunks for level 'world_the_end'/The End

Here's a picture of the midair snow problem. http://i.imgur.com/ensATBa.jpg

Please provide the seasons config.

Seasons:
  Summer:
    Visual:
      Textures: ''
      Snow: 0
    ShortName: summer
    Lengths:
      Season: 10.0
      Weather: 0.5
    Percentages:
      Sun: 70
      Rain: 20
      Thunder: 10
    SpecialDays:
      '1': First Day of Summer
      '10': Last Day of Summer
    SnowManagerSpeed:
      Place: 0
      Remove: 0
    Time:
      Day: 14000
      Night: 10000
  Winter:
    Visual:
      Textures: ''
      Snow: 100
    ShortName: winter
    Lengths:
      Season: 5.0
      Weather: 0.5
    Percentages:
      Sun: 30
      Rain: 60
      Thunder: 10
    SpecialDays:
      '1': First Day of Winter
      '3': Mid Winter
      '5': Last Day of Winter
    SnowManagerSpeed:
      Place: 1
      Remove: 0
    Time:
      Day: 14000
      Night: 10000
Properties:
  Active: true
  LogInfo: true
  Resolution:
    Precision: 0.01
    TimeCheck: 20
  Regen:
    Snow: true
    Ice: true

Any more informations ?

So I had a friend test this bug (and my the other one) and following my steps he was able to cause the problem easily.

Ok so reducing view distance from 10 to 7 solved the problem. However, it still an issue as it was just me. Although I can/will definitely test it with multiple people to figure out what setting works, I was planning on a small server (thus allowing for such tests) anyways. This bug is a major restriction to openly public servers.

Also, I took a look at the API JavaDoc. I haven't tried to match up the error code to it yet, but it looks like the fault *might* lay in the amount of blocks allowed in the queue for the SnowManager. Basically, even though the server itself can keep up, the SnowManager might just not have enough space to expand into and crashes. Just a guess, though.