Why does this compile? `var text: String by mutableStateOf(text)` (At runtime it gets "Attempt to in...

# compose

[Rick Regan]

Why does this compile? var text: String by mutableStateOf(text) (At runtime it gets "Attempt to invoke interface method 'java.lang.Object androidx.compose.runtime.State.getValue()' on a null object reference.)

[Zach Klippenstein (he/him) [MOD]]

it looks like perfectly valid code. The runtime issue seems like something’s wrong, maybe a version mismatch?

[Rick Regan]

What does the line mean? It seems circular. var text: MutableState<String> = mutableStateOf(text) gives "Type mismatch. Required: String Found: MutableState<String>"

[Adam Powell]

yeah I don't think this is compose-specific. It's letting you refer to the property of the class that you're declaring in its own initializer expression

[Adam Powell]

and its delegate is predictably null while it's running that initializer expression to create that delegate

[Adam Powell]

out of context it's not unusual to have that exact line of code...when there's also a primary constructor parameter with the same name

[Rick Regan]

That's how I ran across it -- I deleted the constructor parameter without changing anything else. Thanks.