## Summary
Fixes#24147
- Fixed EventEmitter crash when `removeAllListeners()` is called from
within an event handler while a `removeListener` meta-listener is
registered
- Added undefined check before iterating over listeners array to match
Node.js behavior
- Added comprehensive regression tests
## Bug Description
When `removeAllListeners(type)` was called:
1. From within an event handler
2. While a `removeListener` meta-listener was registered
3. For an event type with no listeners
It would crash with: `TypeError: undefined is not an object (evaluating
'this._events')`
## Root Cause
The `removeAllListeners` function tried to access `listeners.length`
without checking if `listeners` was defined first. When called with an
event type that had no listeners, `events[type]` returned `undefined`,
causing the crash.
## Fix
Added a check `if (listeners !== undefined)` before iterating, matching
the behavior in Node.js core:
https://github.com/nodejs/node/blob/main/lib/events.js#L768
## Test plan
- ✅ Created regression test in `test/regression/issue/24147.test.ts`
- ✅ Verified test fails with `USE_SYSTEM_BUN=1 bun test` (reproduces
bug)
- ✅ Verified test passes with `bun bd test` (confirms fix)
- ✅ Test covers the exact reproduction case from the issue
- ✅ Additional tests for edge cases (actual listeners, nested calls)
🤖 Generated with [Claude Code](https://claude.com/claude-code)
---------
Co-authored-by: Claude Bot <claude-bot@bun.sh>
Co-authored-by: Claude <noreply@anthropic.com>
