A lot of false-positives and false-negative related with wrong classpath

[BraisGabin]

It seems that the Kotlin compiler between 1.5.21 and 1.5.31 changed a lot. I'm updating the project where I work from 1.18.1 to 1.19.1-RC1 and I'm getting a lot of false-positives and false-negative in different rules. Some examples:

• DoubleMutabilityForCollection
• ImplicitUnitReturnType
• HasPlatformType
• MissingWhenCase
• RedundantSuspendModifier
• ReplaceSafeCallChainWithRun
• UnnecessaryLet
• UnreachableCode
• UnsafeCast
• UnusedPrivateMember

I think that all of them are related with the type-solving and problems in the BindingContext that end up creating false positive and negative issues. Until now, in general, this type of problems generated false-negatives. Those are bad, but at least they don't generate noise. But with this release I'm seeing a lot of false-positives too.

[BraisGabin]

🤔 maybe this is not related with the Kotlin compiler at all but something that we did. Checking the logs I see messages like this one:

error: supertypes of the following classes cannot be resolved. Please make sure you have the required dependencies in the classpath:
    class foo.bar.DataClassName, unresolved supertypes: android.os.Parcelable
    class androidx.core.app.ComponentActivity, unresolved supertypes: android.app.Activity
    class androidx.drawerlayout.widget.DrawerLayout, unresolved supertypes: android.view.ViewGroup
    class androidx.fragment.app.Fragment, unresolved supertypes: android.content.ComponentCallbacks, android.view.View.OnCreateContextMenuListener
    class androidx.recyclerview.widget.RecyclerView, unresolved supertypes: android.view.ViewGroup
    class androidx.appcompat.app.AlertDialog, unresolved supertypes: android.content.DialogInterface
    class androidx.appcompat.app.AppCompatDialog, unresolved supertypes: android.app.Dialog
    class com.chauthai.swipereveallayout.SwipeRevealLayout, unresolved supertypes: android.view.ViewGroup
Adding -Xextended-compiler-checks argument might provide additional information.

Those errors doesn't appears on 1.18.1. I think that in 1.18.1 we were able to resolve types like android.os.Parcelable. That should be in android.jar but for some reason this is broken in 1.19.0-RC1

[cortinico]

Are you able to bisect in any form?

[BraisGabin]

I think that it should doable using composite build. But I never used them. Probably we should add to our documentation a guide about how to do this. It would help a lot in this cases. Or for a new rule that you write and you want to test it in your project directly.

[BraisGabin]

Using composite builds is way easier than I expected. One point for gradle this time!

It seems that this regression was introduced at 44b7660. @3flex any idea why can this be happening? Maybe the afterEvaluate was needed.

[3flex]

Thanks for investigating!

I suggest reverting that commit then pushing RC2 to see if this and #4250 are resolved.

Not sure when I'll be able to properly investigate and attempt that change again, but it's clear we need a functional test to ensure correct behaviour.

[eygraber]

Edit: I saw RC2 but missed the date on this issue. I'm assuming it's not related

I'm getting a lot of false positives for:

UnusedImports // https://github.com/detekt/detekt/issues/5502
RedundantSuspendModifier
UnreachableCode

It seems like all of the false positives are related to either an androidx.core.* import, or something in the function signature coming from an androidx or com.google package.

This only started happening in 1.22.0-RC2 and does not happen in 1.22.0-RC1

[BraisGabin]

Yes, this is a known issue of RC2. We plan to release a RC3 once this issue is fixed.