panic: runtime error: invalid memory address or nil pointer dereference in golang-CodePudding

I run this code in my mac. I test it and it is ok. But i compile it and start it at aws ecs. I get this error

panic: runtime error: invalid memory address or nil pointer dereference

[signal SIGSEGV: segmentation violation code=0x1 addr=0x10 pc=0x55fff8]

goroutine 6 [running]:

go.sia.tech/siad/types.NewCurrency(0xc0000d5640)

/Users/jaslin.wang/go/pkg/mod/go.sia.tech/[email protected]/types/currency.go:57  0x18

There is my code. It get error when call this line 80

74 amount, _ := new(big.Int).SetString(output.Value, 10)
75
76 addr := types.UnlockHash{}
77 addr.LoadString(output.Address)
78
79 sco := types.SiacoinOutput{
80   Value:      types.NewCurrency(amount),
81   UnlockHash: addr,
82 }

There is NewCurrency function

56 func NewCurrency(b *big.Int) (c Currency) {
57 if b.Sign() < 0 {
58  build.Critical(ErrNegativeCurrency)
59 } else {
60  c.i = *b
61 }
62 return

}

There is my compile command

CGO_ENABLED=0 GOOS=linux GOARCH=amd64 go build

Thanks very much!

CodePudding user response：

2022/08/30 03:30:05 output.Value is 340900000000000000000000000.000000000000000000000000000000000000000000000000000000

2022-08-30T11:30:05.726 08:00   2022/08/30 03:30:05 ok is false

2022-08-30T11:30:05.726 08:00   2022/08/30 03:30:05 amount is <nil>

sry to bother you guys. I don't know why output.Value is 340900000000000000000000000.000000000000000000000000000000000000000000000000000000. It should be 340900000000000000000000000. But i think change it to 340900000000000000000000000 will fix this issue. Thank all of you!

CodePudding user response：

You need to check whether big.SetString() actually parsed the value. Try running this code to see it happen... Presumably SetString() is not parsing your value because you're using a big.Int() and passing it a string with floating point decimals (even if they are zeroes).

package main

import (
    "fmt"
    "math/big"
)

type Currency struct {
    i big.Int
}

func main() {
    for _, v := range []string{"1234567878768376294872638", "boom!"} {
        amount, ok := new(big.Int).SetString(v, 10)
        if !ok {
            fmt.Println("Expecting this will go boom!")
        }
        x := NewCurrency(amount)
        fmt.Println(x)
    }
}

func NewCurrency(b *big.Int) (c Currency) {
    if b.Sign() < 0 {
        fmt.Printf("Error negative currency")
        panic("panicking!")
    } else {
        c.i = *b
    }
    return
}