rspec/rules/S1871/kotlin/rule.adoc

Having two clauses in a ``when`` statement or two branches in an ``if`` chain with the same implementation is at best duplicate code, and at worst a coding error. If the same logic is truly needed for both instances, then in an ``if`` chain they should be combined, or for a ``when``, duplicates should be refactored. 

== Noncompliant Code Example

----
fun s1871(x: Int) {
    when (x) {
        1 -> {
            val y = x / 2
            print(y)
        }
        2 -> {
            val y = x / 2
            print(y)
        }
    }
}
----

== Exceptions

Blocks in an ``if`` chain that contain a single line of code are ignored, as are blocks in a ``when`` statement that contain a single line of code with or without a following ``break``.

----
if (a == 1) {
    doSomething()  //no issue, usually this is done on purpose to increase the readability
} else if (a == 2) {
    doSomethingElse()
} else {
    doSomething()
}
----

But this exception does not apply to ``if`` chains without ``else``-s, or to ``when``-es without ``else`` clauses when all branches have the same single line of code. In case of ``if`` chains with ``else``-s, or of ``when``-es with default clauses, rule S3923 raises a bug. 

----
if (a == 1) {
  doSomething()  //Noncompliant, this might have been done on purpose but probably not
} else if (a == 2) {
  doSomething()
}
----