IssueTracker

The putStringArray function in Data.Builder is declared as

fun putStringArray(key: String, value: Array<String?>): Builder

and therefore you can construct a Data instance containing an array with nulls via e.g.

Data.Builder()
    .putStringArray("array", arrayOf("foo", null, "bar"))
    .build()

this works and throws no exceptions. However, you can never retrieve the array because getStringArray in Data is defined as

fun getStringArray(key: String): Array<String>? = getTypedArray(key, ::Array)

You can cast the result to Array<String?>? to supress the type error, but then a NullPointerException is thrown because getTypedArray tries to cast every element to a (non-null) String.

Here is a basic JUnit Test for the issue:

@Test
fun `string array round trip`() {
    val array = arrayOf("foo", null, "bar")
    val data = Data.Builder().putStringArray("array", array).build()
    assertContentEquals(array, data.getStringArray("array") as Array<String?>?)
}