invalid memory address or nil pointer dereference when chaining methods

[alexballas]

package main

import (
	"fmt"
	"log"
	"net/http"
	"time"

	"github.com/anaskhan96/soup"
)

func main() {
	go func() {
		http.ListenAndServe(":12345", http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
			fmt.Fprint(w, "OK")
		}))
	}()

	time.Sleep(time.Second)

	resp, err := soup.Get("http://127.0.0.1:12345/")
	if err != nil {
		log.Println("Error:", err.Error())
		return
	}

	doc := soup.HTMLParse(resp)
	r := doc.Find("Semething").Find("SomethingElse")
	fmt.Println(r.Error)
}

Hello, If I try to chain Find and FindAll method of non-existent tags like in the example above, I get a panic error

$ go run .
panic: runtime error: invalid memory address or nil pointer dereference
[signal SIGSEGV: segmentation violation code=0x1 addr=0x8 pc=0x66ce1b]

goroutine 1 [running]:
github.com/anaskhan96/soup.findOnce(0x6b64c0?, {0xc00011fe50?, 0x1, 0x1}, 0x2?, 0x0)
        /home/alex/go/pkg/mod/github.com/anaskhan96/[email protected]/soup.go:502 +0xfb
github.com/anaskhan96/soup.Root.Find({0x0, {0x0, 0x0}, {0x766ee0, 0xc000238030}}, {0xc00011fe50?, 0x1, 0x1})
        /home/alex/go/pkg/mod/github.com/anaskhan96/[email protected]/soup.go:268 +0xa5
main.main()
        /home/alex/test/play3/main.go:24 +0x1ca
exit status 2

I believe that both func findOnce and func findAllofem should be checking if n *html.Node is nil before proceeding with the processing. Am I understanding this correctly?

Thanks, Alex

[akmubi]

Yep, I think if findOnce and findAllofem return a pointer to an empty html.Node, it'll be fixed. If we just add the nil pointer check, then the next panic will happen in the Find function because it accesses the Data field.

[denislituev]

https://github.com/anaskhan96/soup/pull/78