Range variables in a loop are reused at each iteration; therefore a goroutine created in a loop will point to the range variable with from the upper scope. This way, the goroutine could use the variable with an undesired value. This rule warns when a range value (or index) is used inside a closure.

Bad practice

mySlice := []string{"A", "B", "C"}
for index, value := range mySlice {
    go func() {
        fmt.Printf("Index: %d\n", index)
        fmt.Printf("Value: %s\n", value)
    }()
}

Recommended

mySlice := []string{"A", "B", "C"}
for index, value := range mySlice {
    index := index
    value := value
    go func() {
        fmt.Printf("Index: %d\n", index)
        fmt.Printf("Value: %s\n", value)
    }()
}

btwiuse / k0s

No ignore rules found