math/big: SetBytes allows arbitrary numbers of leading zeros

[hillar]

package main

import (
    "fmt"
    "math/big"
)

func main() {

    tmp := new(big.Int)

    b := []byte{0x80}
    fmt.Println("%b",b)
    tmp.SetBytes(b)
    fmt.Println("%+d",tmp)

    b00 := []byte{0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x80}
    fmt.Println("%b",b00)
    tmp.SetBytes(b00)
    fmt.Println("%+d",tmp)

}

%b [128]
%+d 128
%b [0 0 0 0 0 0 0 0 0 0 0 0 128]
%+d 128

[griesemer]

This is working as intended. Keep in mind that SetBytes simply sets x to a valid binary value of a number. The number value is unchanged, no matter how many leading 0's there are.

See also #12231.