[go-nuts] A little weird thing in using finalizer

[T L]

The following program might print:

31
> 37
> 47
> 47
> 37
> 31
>

or 

31
> 37
> 47
> 47
>

but with the highest possibility to print

31
> 37
> 47
>

Is not normal?


package main

import (
    "fmt"
    "math/rand"
    "runtime"
    "time"
    "unsafe"
)

type Foo struct {
    x int
    a int
}

func main() {
    for i := 0; i < 3; i++ {
        f := NewFoo(i)
        println(f.a)
    }

    runtime.GC()
    
    time.After(time.Second)
}

func do(i *uint) {
    runtime.SetFinalizer(i, func(f *uint) {
        fmt.Println(*f)
    })
}

//go:noinline
func NewFoo(i int) *Foo {
    f := &Foo{a: rand.Intn(50)}
    
    do((*uint)(unsafe.Pointer(&f.a)))

    return f
}

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