Metadata

ID: go-best-practices/comparing-address-nil

Language: Go

Severity: Info

Category: Best Practices

Description

The code if &x == nil is not recommended in Go and should be avoided.

Here are a few reasons why:

1. Incorrect Comparison: In Go, comparing the address of a variable &x directly to nil using == is not a valid or meaningful comparison. The address of a variable is a memory location and cannot be directly compared to nil to check for its value.
2. Pointer Check: Comparing the address of a variable to nil using == does not accurately check if the variable itself is nil. It only checks if the address is null, not the value stored at that address.
3. Incorrect Usage of nil: In Go, nil is typically used to check if a pointer or reference type is uninitialized or doesn’t point to a valid object. It is not meant to be used to compare the address of a variable.

To check if a variable is nil, you should directly compare its value to nil without taking its address:

if x == nil {
    // Code block
}

This is the correct and idiomatic way to check if a variable is nil in Go.

By avoiding the usage of &x == nil and using x == nil instead, you can write cleaner and more accurate code that adheres to Go’s best practices.

Non-Compliant Code Examples

func main() {
    if &myVar == nil {

    }
}

Compliant Code Examples

func main() {
    var ptr *int = &myVar
    if ptr == nil {

    }
}