Xamarin.Firebase.Crashlytics.NDK packages firebase-crashlytics-ndk twice (embedded AAR + XamarinBuildDownload), causing duplicate XA4301 warnings

[tomcurran]

Android framework version

net10.0-android

Affected platform version

.NET SDK 10.0.400, macOS 15 (Apple Silicon)

Description

Xamarin.Firebase.Crashlytics.NDK includes the Google Maven artifact com.google.firebase:firebase-crashlytics-ndk twice, which produces XA4301 duplicate-native-library warnings in every Android build that references the package:

warning XA4301: APK already contains the item lib/arm64-v8a/libcrashlytics-common.so; ignoring.
warning XA4301: APK already contains the item lib/arm64-v8a/libcrashlytics-handler.so; ignoring.
warning XA4301: APK already contains the item lib/arm64-v8a/libcrashlytics-trampoline.so; ignoring.
warning XA4301: APK already contains the item lib/arm64-v8a/libcrashlytics.so; ignoring.

(4 libraries × 4 ABIs = 16 warnings per build.)

The two copies come from the same NuGet package through two different mechanisms:

1. The AAR embedded in the package itself: lib/net10.0-android36.0/firebase-crashlytics-ndk.aar.
2. The same artifact downloaded again at build time by Xamarin.Build.Download: buildTransitive/net10.0-android36.0/Xamarin.Firebase.Crashlytics.NDK.targets declares a XamarinBuildDownload item for https://dl.google.com/dl/android/maven2/com/google/firebase/firebase-crashlytics-ndk/20.0.6/firebase-crashlytics-ndk-20.0.6.aar.

Mapping evidence from obj/Debug/net10.0-android/libraryprojectimports.cache (observed with 120.0.6):

lp/239 <- ~/.nuget/packages/xamarin.firebase.crashlytics.ndk/120.0.6/lib/net10.0-android36.0/firebase-crashlytics-ndk.aar
lp/310 <- ~/Library/Caches/XamarinBuildDownload/firebasecrashlyticsndk-20.0.6/firebasecrashlyticsndk-20.0.6.aar

The targets file also registers the downloaded AAR twice (identical consecutive lines):

<ItemGroup>
  <XamarinBuildDownloadAndroidAarLibrary Include="$(XamarinBuildDownloadDir)firebasecrashlyticsndk-20.0.6\firebasecrashlyticsndk-20.0.6.aar" />
  <XamarinBuildDownloadAndroidAarLibrary Include="$(XamarinBuildDownloadDir)firebasecrashlyticsndk-20.0.6\firebasecrashlyticsndk-20.0.6.aar" />
</ItemGroup>

I verified the latest release 120.1.0 (published 2026-07-15) still both embeds lib/net10.0-android36.0/firebase-crashlytics-ndk.aar and carries the XamarinBuildDownload targets, so all currently shipping versions are affected. Xamarin.Firebase.Crashlytics has the same double-inclusion of firebase-crashlytics.aar; it just doesn't warn because that AAR carries no jni/ libraries.

This is the same defect that #1519 reported for Xamarin.Google.MLKit.BarcodeScanning, and the template fix merged in #1520 should already cover these packages — both firebase-crashlytics entries in config.json are "type": "xbd". What's missing is a re-release: could the nugetVersion for Xamarin.Firebase.Crashlytics / Xamarin.Firebase.Crashlytics.NDK be bumped so packages regenerated with the fixed templates ship to NuGet?