Null Pointer Exception Potential

[exgalibas]

No description provided.

[wu-sheng]

Why we have npe here? What is the case?

[mrproliu]

Please add more scenario description here, why we need this kind of check?

[exgalibas]

Please add more scenario description here, why we need this kind of check?

because Entity is interface, go interface contains type and data, when type is not nil, the interface will not be nil, but the data can be nil, show some code example:
type Entity interface {
Do()
}

type ImpEntity struct {
Name string
}

func (e *ImpEntity) Do() {
fmt.Println(e.Name)
}

func main() {
var i *ImpEntity
fmt.Println(i == nil) // true
Test(i)
}

func Test(e Entity) {
if e != nil { // not nil
e.Do() // panic
}
}
so when tracer.ServiceEntity is nil, will panic

[mrproliu]

Then, can we use the reflect.ValueOf().IsNil() to judgment the reference is nil or not? The reflect is the more lower level case, we can use the standard way to do this.

[mrproliu]

Also, we have change the implementation into the core, please sync the upstream to fix it.