Go Panic: Nil Pointer Dereference — Complete Guide

What Does This Error Mean?

A nil pointer dereference happens when you try to access a field or method on a pointer that is nil (Go's equivalent of null). The program panics and crashes.

Common Causes

• Uninitialized struct pointer
• Function returning nil that you didn't check
• Map access returning zero-value pointer

How to Fix It

1. Always check for nil

result, err := doSomething()
if err != nil {
    return err
}
// safe to use result now

2. Initialize pointers

// Before (nil)
var p *MyStruct

// After (initialized)
p := &MyStruct{}