EC
runtime panic (slice bounds out of range)
GoCRITICALCommonRuntime

runtime error: slice bounds out of range [low:high]

Quick Answer

Validate that 0 <= low <= high <= cap before any slice expression to prevent this panic.

What this means

A panic caused by a slice expression where the bounds are invalid, such as low > high or high > cap. Commonly an off-by-one or logic error.

Why it happens
  1. 1Slice expression s[low:high] where high exceeds cap(s)
  2. 2Negative or inverted bounds such as s[5:2]

Fix

Validate bounds before slicing

Validate bounds before slicing
if end > len(data) { end = len(data) }
chunk := data[start:end]

Why this works

Clamping end to len(data) ensures the slice expression stays within valid bounds.

Code examples
Safe slicego
end := min(start+size, len(data))
chunk := data[start:end]
Validate manuallygo
if lo > hi || hi > len(s) {
    return nil, errors.New("bad bounds")
}
out := s[lo:hi]
Recovergo
defer func() {
    if r := recover(); r != nil {
        log.Println("slice panic:", r)
    }
}()

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