Status of item duplication in PaperMC - so called "dupes"

Hi,
someone on one of my servers told me that he is duplicating items on the most recent version of paper ( 15.2 Paper-298) Is this a thing? Is this being actively patched? Or is this ok with everyone.

Ask him how, ask him for more details. Then if you know for sure it works create a issue on github.

As far as i am aware i think most dupes are patched. But who knows maybe he got one that works.

Make sure to try it out on the latest build of paper.

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Ok, so you are actively persuing this kind of cheat activities? I pull the most recent version of paper within each major version every night. So I will ask him and open an issue on github

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I think item duping is a huge issue to a big chunk of server owners, so I’d assume the Paper (and for that matter Bukkit/Spigot) people would prioritize something like that once made aware.

With that said, it is very possible for a dupe bug to be accidentally introduced in a new build and then not discovered until later. It then becomes also possible for the bad guys to find it first and cause a little mayhem before the good guys catch up. Now I’ve only been using Paper for about 8 months so I don’t know how often (if at all) this has happened in the past, but I’ve seen builds pushed just to revert a recent change that caused a problem (but not a dupe).

Because of this, I wouldn’t recommend updating every single build like it’s hot bread. I mean, it IS hot bread and by some of the finest chefs in the world, but you know the recipe is still experimental and not exactly FDA approved. Personally I only update when there’s a change that peeks my attention (anything related to chunk loading works for me LOL), or if something’s broken, or when I’m so far behind Paper starts warning me my build is too old on server startup.

You should update often, but, sticking behind a few builds is somewhat norm/semi recommended, making sure that you keep your eyes out for fixes, etc, when you do update… Otherwise you end up in build debt and when you do finally update, nobody really cares to help you figure out the mess as you just jumped 30/40/50, etc versions

As for duplication issues, they’re known, some are highly more complex than others in fixing, some will verge on impossible without impacting too much of other aspects of the game, etc; duplication issues are really a slippery slope, especially when you need to find a way to reproduce stuff consistently in a 1 man debug environment

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my docker container updates everyday using watchtower. =)

https://hub.docker.com/r/marctv/minecraft-papermc-server

The general course-of-action for this should be

  1. Make sure you’re running the latest build
  2. See if the dupe still works
    • Ask the friend how he’s doing it
    • If he’s playing coy, use some administrative plugin to observe (he’s either lying or doesn’t want it to be patched; in both cases you should observe)
  3. If it still works, check the issue tracker for an existing issue
  4. If it’s not yet reported, create a new issue and fill in all the details