PaperMC / PaperMC/Paper

Incorrect InventoryAction in InventoryClickEvent

Open
#12,926 0 comments 0 reactions 0 assignees View on GitHub

Nobody has claimed this yet.

status: needs triage
Dominant language
Java
Stars
12.7k
Forks
3.5k
Avg merge
3d 13h
Merged PRs (30d)
11

Description

Expected behavior

Left-clicking, right-clicking, or double-left-clicking on oversized stacks should have no effect

Observed/Actual behavior

https://github.com/user-attachments/assets/59045a99-1550-465e-89e0-382e131a447e

PS: Incorrect Item Stack Display in Chests (Shows 64 but Actually 99)

Steps/models to reproduce

1、Create oversized stacks by any means (plugins or direct Minecraft modification)
2、Click it and use plugin to output InventoryAction

Plugin and Datapack List

Only test plugin

Paper version

[17:44:46 INFO]: This server is running Paper version 1.21.8-DEV (2025-08-04T09:03:56Z) (Implementing API version 1.21.8-R0.1-SNAPSHOT)
You are running a development version without access to version information

Running on IDEA (1.21.8-22)

Other

No response

Contributor guide

Open the contributing guide

First steps

  1. Read the whole issue, then the project's contributing guide.
  2. Comment on the issue to say you are picking it up — it saves two people doing the same work.
  3. Fork the repository and make your change on a branch.
  4. Open a pull request that references the issue number.

Research direction

Start by reproducing the oversized-stack clicks described in the issue on Paper 1.21.8-DEV and inspect the InventoryClickEvent path that produces InventoryAction. Done means left-click, right-click, and double-left-click on oversized stacks have no effect and the reported action matches that behavior; verify with the test plugin's output.

Written by the indexing model from the issue text.

Assessment

Tech stack
java
Domain
api
Issue type
Bug
Difficulty
4/5
Estimated time
3-5 days
Activity status
Stale
Clarity
Mostly clear
Newbie friendliness
45/100

Get new issues in your inbox

A short digest of beginner-friendly GitHub issues.