I just updated my app from kotlin-gradle-plugin:1....

# android

[David Alford]

I just updated my app from kotlin-gradle-plugin:1.4.32 to 1.5.10. When I compiled, the following extension method no longer compiles. If I roll back to 1.4.32, it compiles again. (I've inlined some stuff to make it clearer so no need to point out the redundant lambdas. I just want to understand why it worked before, but doesn't now.) If I convert the property to a function, it also works (but i'd prefer to keep it a property).

Code:

val UByteArray.utf8:String
	get() {
		val index = this.indexOf(0u)
		val cleaned = if (index == -1) {
			{ this }()
		}
		else {
			{ this.sliceArray(0 until index) }()
		}
		return cleaned.toByteArray().toString(Charsets.UTF_8)
	}

Error Message:

com.android.tools.r8.errors.b: Field name '$this_<get-utf8>' cannot be represented in dex format.

[ephemient]

similar issue has come up before, https://kotlinlang.slack.com/archives/C0B8M7BUY/p1620924941178700?thread_ts=1620918650.173000&cid=C0B8M7BUY

[ephemient]

seems Kotlin changed how it mangles names for inline classes. Android doesn't follow JVM spec, and it breaks

[David Alford]

I'll take a look. Thanks.

[ephemient]

if it were just the getter name, then probably @JvmName("getUtf8") would work around it

[ephemient]

not sure if it helps with the inner class outer reference name, which is what looks like you're running into, but worth a shot

[David Alford]

I tried changing the utf8 name, but that didn't appear to affect it.

[ephemient]

change the getter name

[ephemient]

e.g. @get:JvmName("getUtf8") val UByteArray.utf8: String get() = ... or val UByteArray.utf8: String @JvmName("getUtf8") get() = ...

[David Alford]

I see. Let me give that a whirl.

[David Alford]

Neither of those fix it.

[ephemient]

yeah, it seems the JvmName doesn't have any impact on the outer reference field name. your only workaround is probably to make the lambdas not close over this (or extract them to a non-extension function, same thing)

[ephemient]

should probably file a YouTrack with mcve, I don't see any existing

[ephemient]

workaround:

val self = this
{ self }()

etc.

[David Alford]

Maybe a dumb question, but why does closing lambdas over "this" fall afoul of a field name filter?

[David Alford]

Anyway, thanks for your help.

[ephemient]

the class synthesized for the lambda needs to store a reference to the outer this in a field. apparently that field is getting a name mangled in a way that isn't compatible with Android.