How to check if a “lateinit” variable has been initialized?

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I wonder if there is a way to check if a lateinit variable has been initialized. For example:

class Foo() {

    private lateinit var myFile: File

    fun bar(path: String?) {
        path?.let { myFile = File(it) }
    }

    fun bar2() {
        myFile.whateverMethod()
        // May crash since I don't know whether myFile has been initialized
    }
}

10 s
10

There is a lateinit improvement in Kotlin 1.2 that allows to check the initialization state of lateinit variable directly:

lateinit var file: File    

if (this::file.isInitialized) { ... }

See the annoucement on JetBrains blog or the KEEP proposal.

UPDATE: Kotlin 1.2 has been released. You can find lateinit enhancements here:

  • Checking whether a lateinit var is initialized
  • Lateinit top-level properties and local variables

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