How Can I Detect if a Struct Property Has Been Set in Go?

Detecting Modified Properties in Structs

In Go, determining if a property of a struct has been set can be challenging. Unlike other languages, there is no built-in mechanism to check for uninitialized values in structures.

Using Pointers (dyoo's Suggestion)

As mentioned by dyoo, using pointers for struct properties allows you to differentiate between set and unset values. If the pointer is nil, the value is considered unset.

Example with Pointers:

type MyStruct struct {
    Property *string
}

// ...

if s1.Property != nil {
    // do something with this
}

Using Empty Strings (Maintainer's Response)

If you prefer to use strings instead of pointers, you can compare the value with an empty string to determine if it has been set.

Example with Strings:

type MyStruct struct {
    Property string
}

// ...

if s1.Property != "" {
    // do something with this
}

In the provided code sample, s1.Property has a non-empty value and will be considered set, while s2.Property is empty and will be considered unset.

Alternative Methods

In addition to the mentioned approaches, you can explore other options such as using reflection or defining your own setter functions that track changes in the property's value. However, these methods may require additional code and complexity.

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