Xamarin.Firebase.Firestore 126.0.2.3 fails to build on .NET 9 Android due to ServerListenerImplementor missing transportCreated(ServerTransport)

[Djondo000]

Android framework version

net9.0-android

Affected platform version

Visual Studio 2022 17.14.x .NET SDK 9.0.307 Microsoft.Android.Sdk 35.0.78

Description

Summary

A brand new .NET 9 Android project fails to build after installing only Xamarin.Firebase.Firestore version 126.0.2.3.

No application code is added. The project builds successfully before installing the package.

The build fails during Java compilation with:

ServerListenerImplementor is not abstract and does not override abstract method transportCreated(ServerTransport) in ServerListener

The generated file is:

obj\Debug\net9.0-android\android\src\mono\io\grpc\internal\ServerListenerImplementor.java

The generated implementor contains only:

public void serverShutdown()

while the Java interface io.grpc.internal.ServerListener requires an additional method:

transportCreated(ServerTransport)

This appears to indicate a mismatch between the generated Xamarin.Grpc.Core binding and the bundled gRPC Java library.

The project contains only one NuGet package:

Xamarin.Firebase.Firestore 126.0.2.3

The issue is reproducible with a completely empty project.

Steps to Reproduce

1. Create a new .NET 9 Android App.

2. Set the project minimum SDK to 23.

<SupportedOSPlatformVersion>23.0</SupportedOSPlatformVersion>

3. Install:

Xamarin.Firebase.Firestore 126.0.2.3

4. Build the project.

Expected result

The project builds successfully.

Actual result

Compilation fails with:

ServerListenerImplementor is not abstract and does not override abstract method transportCreated(ServerTransport) in ServerListener

The generated file:

obj\Debug\net9.0-android\android\src\mono\io\grpc\internal\ServerListenerImplementor.java

contains only:

public void serverShutdown()

although the interface requires transportCreated(ServerTransport).

Additional information

dotnet --version
9.0.307

The project contains no application code and no other NuGet packages besides Xamarin.Firebase.Firestore.

Did you find any workaround?

No response

Relevant log output