# panic: time: Reset called on timer that has already fired or been stopped

- **ID:** `go/goroutine-timer-reset-after-expiry`
- **Domain:** go
- **Category:** runtime_error
- **Verification:** ai_generated
- **Fix Rate:** 80%

## Root Cause

Calling Reset() on a time.Timer that has already expired or been stopped, which is not allowed in Go 1.18+ without proper draining.

## Version Compatibility

| Version | Status | Introduced | Deprecated |
|---------|--------|------------|------------|
| 1.18 | active | — | — |
| 1.19 | active | — | — |
| 1.20 | active | — | — |
| 1.21 | active | — | — |
| 1.22 | active | — | — |

## Workarounds

1. **Drain timer channel before Reset** (95% success)
   ```
   if !t.Stop() { <-t.C }; t.Reset(duration)
   ```
2. **Use time.NewTimer and avoid Reset** (90% success)
   ```
   t := time.NewTimer(duration); // use once and recreate if needed
   ```

## Dead Ends

- **Using recover() to ignore panic** — Does not fix timer state issue. (90% fail)
- **Calling Stop() before Reset() without draining** — Stop() returns false if already fired, but Reset still panics if channel not drained. (85% fail)