MaxListenersExceededWarning: Possible EventTarget memory leak detected in effect/Evaluate

[zhoumoxingqt-cmd]

Description

What happened?
While using OpenCode, I encountered a MaxListenersExceededWarning indicating that 11 event listeners were added to an EventEmitter (identified as yZ), exceeding the default limit of 10. The warning suggests a potential memory leak.

The stack trace points to internal effect evaluation (~effect/Effect/evaluate) and run-loop logic, which appears to be part of OpenCode's reactivity system.

Full warning:

text
MaxListenersExceededWarning: Possible EventTarget memory leak detected. 11 event listeners added to [yZ]. MaxListeners is undefined. Use events.setMaxListeners() to increase limit
at overflowWarning (node:events:185:19)
at addListener (node:events:158:22)
at ~effect/Effect/evaluate (/$bunfs/root/chunk-xvx3wx9t.js:25:4492)
at runLoop (/$bunfs/root/chunk-xvx3wx9t.js:25:2045)
at evaluate (/$bunfs/root/chunk-xvx3wx9t.js:25:1435)
at runTasks (/$bunfs/root/chunk-xvx3wx9t.js:11:12750)
at afterScheduled (/$bunfs/root/chunk-xvx3wx9t.js:11:12637)
The emitter object shows _maxListeners: undefined, which uses the default limit of 10.

Plugins

Please list any plugins you have enabled: (I'm not using any third-party plugins; this is a vanilla OpenCode installation.)

OpenCode version

No response

Steps to reproduce

Start OpenCode (version unspecified).

Perform actions that trigger reactive updates – in my case, the warning appeared during normal usage (e.g., editing a file, running a command, or switching contexts).

Observe the warning in the terminal/console after repeated interactions.

(I haven't isolated a minimal reproducible case yet, but the warning occurs consistently under load.)

Screenshot and/or share link

No response

Operating System

No response

Terminal

No response

[github-actions]

This issue doesn't fully meet our contributing guidelines.

What needs to be fixed:

• OpenCode version is missing (_No response_) — please provide the exact version (run opencode --version)
• Operating System is missing (_No response_) — please specify your OS and version
• Terminal is missing (_No response_) — please specify which terminal emulator you use
• Steps to reproduce are too vague — the version is unspecified and you note you haven't isolated a reproducible case; please try to narrow it down further

Please edit this issue to address the above within 2 hours, or it will be automatically closed.

---

This issue might be a duplicate of existing issues. Please check:

• [BUG] MaxListenersExceededWarning #31622: [BUG] MaxListenersExceededWarning — same warning
• MaxListenersExceededWarning after web interface starts #28492: MaxListenersExceededWarning after web interface starts — same warning
• Memory leak in server mode: unbounded EventTarget listeners added to Effect-ts internal emitter (QL) per session #29204: Memory leak in server mode: unbounded EventTarget listeners added to Effect-ts internal emitter per session — same root cause (Effect-ts EventTarget listener leak)
• Memory leak in AI SDK Effect runtime — EventTarget listeners never cleaned up #34574: Memory leak in AI SDK Effect runtime — EventTarget listeners never cleaned up — same root cause
• fix: false MaxListenersExceededWarning on GlobalBus during normal event fanout #23798: fix: false MaxListenersExceededWarning on GlobalBus during normal event fanout — related
• Memory Megathread #20695: Memory Megathread — umbrella issue tracking memory/listener leaks

Please review these issues before proceeding, as your report may already be tracked.

If you believe this was flagged incorrectly, please let a maintainer know.

[github-actions]

This issue has been automatically closed because it was not updated to meet our contributing guidelines within the 2-hour window.

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