Hi guys :slightly_smiling_face: We wrote something like that today during a pair programing session ...

# getting-started

[Jérémy CROS]

Hi guys 🙂
We wrote something like that today during a pair programing session and it occurred to us that we had no idea what the lifecycle of the variable was.

private var aVariableToKeepTrackOfSomeData : SomeClass? = null

fun AnotherClass.myExtentionFunction() {
    // do stuff here with the variable
}

Is it scoped to the application?
Does that look like a bad idea? 😅

[Sam]

The lifecycle is the same as the application, yes. The scope is the file in which it’s declared, since it’s marked private.

[Sam]

Whether it’s a bad idea really depends on how you’re using it 😄

[Sam]

But it’s quite likely to be a bad idea if you’re mutating it as a side effect of an extension function. It could make testing very difficult, it could introduce problems when multithreading, and it could confuse people who are calling the function.

[Jérémy CROS]

Ok, that’s what we figured, thanks for confirmation and explanations 🙏

[Robert Williams]

If you really care about implementation details the lifecycle is controlled by the ClassLoader that loads the Class generated from the file (normally something like FooKt.class)

[Robert Williams]

It's possible in Java to have multiple ClassLoaders with different lifecycles but it normally causes more problems than it solves