How to Pretty-Print Pointer Fields for Debugging in Go?

How to Pretty-Print Pointer Fields for Debugging in Go?

When debugging a Go program, it can be useful to print the contents of structs, including any pointer fields. However, by default, Go prints pointer fields as memory addresses, which may not be helpful.

Consider the following code:

type SomeStruct struct {
    somePointer *somePointer
}
type somePointer struct {
    field string
}

func main() {
    fmt.Println(SomeStruct{&somePointer{"I want to see what is in here"}})
}

This code prints a memory address instead of the desired string value. To print the dereferenced value, you can use the go-spew package.

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

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

This code uses the spew.Dump function to print the contents of the SomeStruct, including the dereferenced values of its pointer fields. The output will be:

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

This output includes the desired string value for the field field of the somePointer struct. The go-spew package provides a convenient way to print structured data in a readable format, making it easier to debug complex structures with nested pointer fields.

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