go runtime_error ai_generated true

panic: runtime error: index out of range [5] with length 3 (in goroutine)

ID: go/goroutine-panic-in-goroutine

Also available as: JSON · Markdown · 中文
80%Fix Rate
87%Confidence
0Evidence
2025-03-12First Seen

Version Compatibility

VersionStatusIntroducedDeprecatedNotes
1.0 active — — —
1.22 active — — —

Root Cause

Goroutine accesses slice or array with out-of-bounds index, causing panic that crashes the entire program if not recovered.

generic

中文

协程使用越界索引访问slice或数组，导致恐慌，如果不恢复则崩溃整个程序。

Workarounds

  1. 90% success Use recover() inside the goroutine to handle panic 
    go func() {
    defer func() {
        if r := recover(); r != nil {
            log.Println("recovered from panic:", r)
        }
    }()
    arr := []int{1,2,3}
    fmt.Println(arr[5])
}()
  2. 95% success Always check bounds before accessing slice 
    if idx < len(arr) {
    fmt.Println(arr[idx])
} else {
    log.Println("index out of bounds")
}

Dead Ends

Common approaches that don't work:

  1. Ignoring panic and hoping it doesn't happen 100% fail

    Panic crashes the program; cannot be ignored.

  2. Using recover() in main goroutine only 95% fail

    Recover must be called in the same goroutine that panicked; main goroutine cannot recover from child goroutine panic.