Comapring data class in Kotlin using == operator-CodePudding

I am trying to write an assertion by comparing two Kotlin data classes.I am just simplifying the question by using a minimal class.

data class X(val isThatSo: Boolean) {
  val name:String = "xyz"
}

In my test

val s = """
    {
     "isThatSo": "true",
     "name": "Ankit"
    }
    """

 assert(Gson().fromJson(s, X::class.java) == X(true))

Looks to me that the name field is not compared at all because the value in both the objects is different. Is my understanding correct?

CodePudding user response：

From the documentation:

data class User(val name: String, val age: Int)
The compiler automatically derives the following members from all properties declared in the primary constructor:

equals()/hashCode() pair

toString() of the form "User(name=John, age=42)"

componentN() functions corresponding to the properties in their order of declaration.

copy() function.

To exclude a property from the generated implementations, declare it inside the class body:
data class Person(val name: String) {
    var age: Int = 0
}

CodePudding user response：

You're comparing two instances of a class, which are not identical. You can compare the name variable within X for equality.