How Can I Display the Underlying Values of Pointer Fields in Go Structs During Debugging?

Debugging Pointer Fields

In Go, printing a struct containing pointer fields typically outputs memory addresses rather than the actual values. This can be inconvenient during debugging, especially when dealing with numerous pointer fields.

Dereferencing Pointer Fields

To display the underlying values of pointer fields, one option is to manually dereference each field using the asterisk operator (*). However, this approach becomes tedious for structs with multiple pointer fields.

Using go-spew

Go offers a powerful tool for debugging such scenarios: the go-spew package. This package provides an easy way to deep dive into the structure of any value.

Example

Consider the following code:

package main

import (
    "fmt"
    "github.com/davecgh/go-spew/spew"
)

type SomeStruct struct {
    Field1 string
    Field2 int
    Field3 *somePointer
}

type somePointer struct {
    field string
}

func main() {
    s := SomeStruct{
        Field1: "Yahoo",
        Field2: 500,
        Field3: &somePointer{"I want to see what is in here"},
    }
    spew.Dump(s)
}

When you run this code, it prints the following output:

(main.SomeStruct) {
 Field1: (string) "Yahoo",
 Field2: (int) 500,
 Field3: (*main.somePointer)(0x2102a7230)({
  field: (string) "I want to see what is in here"
 })
}

As you can see, the go-spew package provides a more detailed and structured output, including the underlying values of the pointer fields. This makes debugging and understanding the content of structs much easier.

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