Migrated from: https://dev.bukkit.org/projects/shopkeepers/issues/318

Originally posted by MasterMithrandir (May 24, 2015):

I'm just testing 1.56-ALPHA, Is this error being caused by Shopkeepers?:https://hub.spigotmc.org/jira/browse/SPIGOT-919Video explaining some more issues, including /shopkeeper remove command not working:https://www.youtube.com/watch?v=cJ8gPhR6tNU&feature=youtu.beSorry, I kinda mixed up two different reports here, I hope you don't mind.

Originally commented by MasterMithrandir (May 24, 2015):

Something is really wrong, allthough I've downgraded to 1.55 whith it's own corresponding save.yml it's breaking all the data, and all admin shops get deleted.

I basically can't apply a simple backup back in, because the save.yml breaks (and this save yml has nothing to do whith 1.56, it's all a backup.).
Edited May 24, 2015

Originally commented by blablubbabc (May 25, 2015):

Regarding the first issue: the error stack trace from the spigot ticket, is this the complete stack trace, or are there any other lines in there?
Otherwise, if is really happening this frequently, maybe do a quick try and remove shopkeeper and see if the error still occurs.
Regarding the first issue in the video with the sign shop not being removed:
I think I found the issue for that. Might be because shopkeepers was for some reason storing owner names in lower case initially, which are used when finding the shops of a player. The fix will be included in the next update. Edit: Should be fixed in 1.57.
Regarding the second issue in the video (not being able to interact):
Shopkeepers should already ignore other plugins blocking interaction. So I currently have no idea what could be causing this.

Is this only happening in a certain world or a certain zone in which certain plugins are active?

Are there any errors in the console? Maybe try without ProtocolLib to see if it is somehow involved.

        Edited May 25, 2015

Originally commented by MasterMithrandir (May 25, 2015):

That was the complete stack trace, was, and still is, being sent regularly through console (can't really calculate how fast, as my console is not live, and needs refreshing. Yeah, real shitty console, getting an update soon xD)
I'm actually getting a complete storm of errors since I updated to your alpha build (pure cohincidence?). I knew I shouldn't have done it on my main server, but I was anctious for bug fixing... I can't really confirm the errors I get right now are because of it. It does seem to be a possible cause though.
Here's a continuation ticket, whith some other bugs I found on logs, related, or caused by the initial error:
https://hub.spigotmc.org/jira/browse/SPIGOT-920
(Yeah, it's really messed up. In fact, my Factions world was giving out some sort of corruption error, detailed in second spigot ticket, so It might have something to do whith not being able to select shop types in that world, and even the bow not working + enderpearls, and fishing rod, tools that require right clicking.)
I already removed shopkeepers but that won't help. I've even updated EVERYTHING (except shopkeepers to alpha, remaining on previous version) to it's latest versions, all plugins and the Spigot server itself are updated to their latest versions (Spigot 1.8.5)
The second bug only happens on my Factions world, I've checked, and It works in ANY other world so I'll be investigating this, as it all seems to be related.
I can actually set up a shop on Factions, what I can't do is select shop types by right clicking, it's just strange because since I tried alpha, the Factions world is "corrupted" and I can only attibute this right click bug to the error messages I'm getting since trying shopkeepers alpha.

Originally commented by MasterMithrandir (May 24, 2015):

I've reapplied my previous backup.

Originally closed by blablubbabc (May 25, 2015)

Originally commented by blablubbabc (May 25, 2015):

[at]MasterMithrandir:
If you get the same errors without shopkeepers being active I doubt that shopkeepers is the cause of this.. Also shopkeepers shouldn't be messing with world / chunk saving, which isn't working for you as well.
As bow shooting isn't working and shopkeepers can't detect the player clicking, I assume something is messing something up inside the server, or between the incoming clicking-packets and their handling by the server. The first plugin which comes in mind there is ProtocolLib. So maybe try it without it.
Also you could maybe try to find the very first error in your server log. Maybe the other errors are subsequent errors from another issue.
Also: Do you run BungeeCoord and is your Factions world a separate server or only a separate world?

Also I noticed some strange behavior with one of the latest spigot versions yesterday when I tried to join multiple times very fast my test server, before it actually connected me: The console logged that I tried to connect multiple times. And in the end, when I was finally on the server, some things behaved weird, like that the blocks which I broke not getting broken, but only getting invisible for me until I relog. I think that right clicking wasn't properly working as well.

I might test this later again when I have some time.
In case you world is somehow corrupted, I have no idea how to detect or fix this.. Maybe download the map and see if you get errors even without any plugins running.

        Edited May 25, 2015

Originally commented by MasterMithrandir (May 25, 2015):

Tried retrieving ProtocolLib, restarted the server, error still occurs.
I can also confirm that the error here: https://hub.spigotmc.org/jira/browse/SPIGOT-919
Is related to the Tools not working properly, as now, in maintainance mode, I am the only one shooting a bow, and the error pops up each time I shoot.
This is the main error, but it doesn't seem to have to do whith Shopkeepers. So sorry for bothering you whith this :)
Other errors I have mentioned here: https://hub.spigotmc.org/jira/browse/SPIGOT-920
are either caused by something different, or founded on the main bug.
Null pointer exception is something I see pretty often whith MythicMobs (Now I'm seeing it even without that plugin ON), which may prove Spigot may have some issues.
I don't run Bungee, I have a Factions world, and a Survival world. The factions world recieves all advantages from Boss + NPCTrading systems (your plugin n_n)
My host has a free chunk fixer service included. I don't know if that would help... I'm getting all sorts of errors, I don't even know where to start, so I'm gonna do the good old pluginless server test, and readd all plugins one by one untill I find the cause.