Remove custom change detection code from incremental Java compile

[wolfs]

With #8499, the custom alignment code for incremental Java compilation should not be necessary any more and the normal incremental information can be used.

Maybe we should dogfood after we also support better incremental task inputs.

[wolfs]

The Android Gradle Plugin currently extends JavaCompile with quite some logic which means that moving to InputChanges would be a breaking change for them.

[lptr]

FTR, it also has its own way to specify additional sources, so our workarounds for getSource() could be problematic, too.

[lptr]

@wolfs created an issue on the Android issue tracker: https://issuetracker.google.com/issues/133354240

[lptr]

\o/ https://issuetracker.google.com/issues/133354240#comment9:

This should be released in 3.6.0-alpha05.

Fixed with ag/I1a1a636546a07e38d5a220fdcb2b09b0c376bd2d.

[lptr]

I think this means we can break JavaCompile for extension in 6.0.

[wolfs]

I we break JavaCompile in 6.0, then AGP 3.5 will not work anymore with Gradle 6.0. So no stable version of AGP would work with Gradle 6.0 when it comes out, right? I don't think we can do this...

[lptr]

6.0 GA is planned for end of August now. When is AGP 3.6 planned?

[lptr]

Kotlin extends AbstractCompile only:

https://github.com/JetBrains/kotlin/blob/master/libraries/tools/kotlin-gradle-plugin/src/main/kotlin/org/jetbrains/kotlin/gradle/tasks/Tasks.kt#L267-L272

And it doesn't mess with getSource():

https://github.com/JetBrains/kotlin/blob/master/libraries/tools/kotlin-gradle-plugin/src/main/kotlin/org/jetbrains/kotlin/gradle/tasks/Tasks.kt#L83-L85

[wolfs]

Using InputChanges in JavaCompile is now tracked as part of #9817 and is a requirement for removing the custom change detection code.