Nested Package-Private types should not be bound

[jonpryor]

Context: dotnet/android-libraries#56
Context: https://github.com/xamarin/xamarin-android/issues/4278�

A version of the Xamarin.Google.Android.Material 1.1.0-rc1 NuGet package was released which bound the com.google.android.material.button.MaterialButton.OnPressedChangeListener, which is a package-private type.

Package-private types must not be bound.

The com.google.android.material.button.MaterialButton.OnPressedChangeListener is declared in api.xml as:

 <package name="com.google.android.material.button" jni-name="com/google/android/material/button">
 <interface abstract="true" deprecated="not deprecated" final="false" name="MaterialButton.OnPressedChangeListener" static="true" visibility="" jni-signature="Lcom/google/android/material/button/MaterialButton$OnPressedChangeListener;">
 <method abstract="true" deprecated="not deprecated" final="false" name="onPressedChanged" jni-signature="(Lcom/google/android/material/button/MaterialButton;Z)V" bridge="false" native="false" return="void" jni-return="V" static="false" synchronized="false" synthetic="false" visibility="public">
 <parameter name="p0" type="com.google.android.material.button.MaterialButton" jni-type="Lcom/google/android/material/button/MaterialButton;">
 </parameter>
 <parameter name="p1" type="boolean" jni-type="Z">
 </parameter>
 </method>
 </interface>
 </package>

Note that //interface/@visibility is empty

[moljac]

@jpobst

api.xml
api.zip

[jpobst]

This is because the interface does not have any access modifiers, so class-parse marks it as visibility="".

generator treats visibility="" as public:

https://github.com/xamarin/java.interop/blob/master/tools/generator/Java.Interop.Tools.Generator.ObjectModel/GenBase.cs#L864

This is a simple change, but it breaks a test that seems to be asserting that we need to bind these classes/interfaces. It looks like the scenario is that the base class is package-private but there is a public class that inherits it. This is not a valid scenario in C# (and would require us to generate the base class even though it's "private").

https://github.com/xamarin/java.interop/blob/master/tests/generator-Tests/expected/AccessModifiers/AccessModifiers.xml#L8-L27

[jpobst]

It looks like we have handled this case for:

• public classes inheriting package-private classes: [generator] better support for "package-private" classes #223
• public interfaces inheriting package-private interfaces: [generator] better support for package-private interfaces #471

This case is not handled because it is a public class inheriting a package-private interface.

Assigning to @gugavaro since he did #471.

[jpobst]

Never mind, the issue is we don't run the package-private type removal code on nested types. I'll fix that.

[jpobst]

/azp run