## Summary
- Add `_idleStart` property (getter/setter) to the Timeout object
returned by `setTimeout()` and `setInterval()`
- The property returns a monotonic timestamp (in milliseconds)
representing when the timer was created
- This mimics Node.js's behavior where `_idleStart` is the libuv
timestamp at timer creation time
## Test plan
- [x] Verified test fails with `USE_SYSTEM_BUN=1 bun test
test/regression/issue/25639.test.ts`
- [x] Verified test passes with `bun bd test
test/regression/issue/25639.test.ts`
- [x] Manual verification:
```bash
# Bun with fix - _idleStart exists
./build/debug/bun-debug -e "const t = setTimeout(() => {}, 0);
console.log('_idleStart' in t, typeof t._idleStart); clearTimeout(t)"
# Output: true number
# Node.js reference - same behavior
node -e "const t = setTimeout(() => {}, 0); console.log('_idleStart' in
t, typeof t._idleStart); clearTimeout(t)"
# Output: true number
```
Closes#25639🤖 Generated with [Claude Code](https://claude.com/claude-code)
---------
Co-authored-by: Claude Bot <claude-bot@bun.sh>
Co-authored-by: Claude Opus 4.5 <noreply@anthropic.com>
Fixes ENG-21288
TODO: Test with `@testing-library/react` `waitFor`
---------
Co-authored-by: autofix-ci[bot] <114827586+autofix-ci[bot]@users.noreply.github.com>
Co-authored-by: Claude <noreply@anthropic.com>
## Summary
The `EventLoopTimer.Arm` result from `EventLoopTimer.fire()` was being
ignored at both call sites. This PR removes the unused return type and
simplifies the code.
## Changes
- Changed `EventLoopTimer.fire()` to return `void` instead of `Arm`
- Updated all 15 timer callback functions to return `void`
- Removed the `Arm` type definition
- Simplified the `drainTimers()` loop that was ignoring the return value
- Updated both call sites in `Timer.zig`
## Details
The `.rearm` functionality was unused - timers that need to reschedule
themselves (like DNS resolver) handle this by calling
`addTimer()`/`update()` directly rather than relying on the return
value.
This change removes:
- The `Arm` union enum type (3 lines)
- All `return .disarm` and `return .{ .rearm = ... }` statements
- The switch statement in `drainTimers()` that did nothing with the
return value
Net result: **-58 lines** of dead code removed.
## Testing
- [x] Bun builds successfully with `bun bd`
🤖 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>
### What does this PR do?
On Linux, AbortSignal.timeout created a file descriptor for each timeout
and did not keep the event loop alive when a timer was active. This is
fixed.
### How did you verify your code works?
Fewer flaky tests
---------
Co-authored-by: autofix-ci[bot] <114827586+autofix-ci[bot]@users.noreply.github.com>
Co-authored-by: Claude <claude@anthropic.ai>
