goScope errorMedium

Error handling issue in Go function with shadowed variable

Time: 0:00

BugFind the bug and fix the code

What it should do

Fetch data from a given URL and return the response body. Example: fetchDataWithStatus("http://example.com") -> "example data"

What happens instead

The function executes without errors but does not handle errors correctly, leading to unexpected behavior.

package main 

import (
	"fmt"
	"net/http"
	"io/ioutil"
)

func fetchDataWithStatus(url string) (string, error) {
	resp, err := http.Get(url)
	if err!= nil {
		return "", err
	}
	defer resp.Body.Close()
	
	body, err := ioutil.ReadAll(resp.Body)
	if err!= nil {
		return "", err
	}
	
	if resp.StatusCode!= 200 {
		err := fmt.Errorf("unexpected status code: %d", resp.StatusCode)
		return "", err
	}
	
	return string(body), nil
}

func main() {
	data, err := fetchDataWithStatus("http://example.com")
	if err!= nil {
		fmt.Println("Error:", err)
	}
	fmt.Println(data)
}

Test a custom input to verify an edge case (e.g. empty lists, negative numbers, duplicates).

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This bug belongs to the scope and closure bugs pattern

Every callback reports the last value, a counter never increments, UnboundLocalError on a variable you can see.

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package main import ( "fmt" "net/http" "io/ioutil" ) func fetchDataWithStatus(url string) (string, error) { resp, err := http.Get(url) if err!= nil { return "", err } defer resp.Body.Close() body, err := ioutil.ReadAll(resp.Body) if err!= nil { return "", err } if resp.StatusCode!= 200 { err := fmt.Errorf("unexpected status code: %d", resp.StatusCode) return "", err } return string(body), nil } func main() { data, err := fetchDataWithStatus("http://example.com") if err!= nil { fmt.Println("Error:", err) } fmt.Println(data) }

Error handling issue in Go function with shadowed variable

What it should do

What happens instead

More scope and closure bugs to practise

Error handling issue in Go function with shadowed variable

What it should do

What happens instead

More scope and closure bugs to practise