fix(android): preload NDK integration for CoreCLR

Enable the io.sentry.ndk.preload metadata so that
SentryNdkPreloadProvider installs sentry-native's signal handlers
before .NET/CoreCLR. This ensures the correct handler chain order
(.NET -> sentry-native -> debuggerd) where .NET handles managed
exceptions first, and native crashes chain to sentry-native.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: jpnurmi

integration-test/Directory.Build.targets

@@ -1,3 +1,7 @@
 <Project>
   <!-- Don't include parent Directory.Build.targets -->
+
+  <!-- Needed for SetAndroidNdkPreload (buildTransitive doesn't apply via ProjectReference) -->
+  <Import Project="../src/Sentry/buildTransitive/Sentry.props" Condition="Exists('../src/Sentry/buildTransitive/Sentry.props')" />
+  <Import Project="../src/Sentry/buildTransitive/Sentry.targets" Condition="Exists('../src/Sentry/buildTransitive/Sentry.targets')" />
 </Project>

integration-test/android.Tests.ps1

@@ -18,10 +18,12 @@ BeforeDiscovery {
 }
 
 $cases = @(
-    @{ configuration = 'Release' }
-    @{ configuration = 'Debug'   }
+    @{ configuration = 'Release'; runtime = 'mono'    }
+    @{ configuration = 'Release'; runtime = 'coreclr' }
+    @{ configuration = 'Debug';   runtime = 'mono'    }
+    @{ configuration = 'Debug';   runtime = 'coreclr' }
 )
-Describe 'MAUI app (<dotnet_version>, <configuration>)' -ForEach $cases -Skip:(-not $script:emulator) {
+Describe 'MAUI app (<dotnet_version>, <configuration>, <runtime>)' -ForEach $cases -Skip:(-not $script:emulator) {
     BeforeAll {
         $tfm = "$dotnet_version-android$(GetAndroidTpv $dotnet_version)"
 
@@ -38,10 +40,12 @@ Describe 'MAUI app (<dotnet_version>, <configuration>)' -ForEach $cases -Skip:(-
         $rid = "android-$arch"
 
         Write-Host "::group::Build Sentry.Maui.Device.IntegrationTestApp.csproj"
+        $useMonoRuntime = if ($runtime -eq 'mono') { 'true' } else { 'false' }
         dotnet build Sentry.Maui.Device.IntegrationTestApp.csproj `
             --configuration $configuration `
             --framework $tfm `
-            --runtime $rid
+            --runtime $rid `
+            -p:UseMonoRuntime=$useMonoRuntime
         | ForEach-Object { Write-Host $_ }
         Write-Host '::endgroup::'
         $LASTEXITCODE | Should -Be 0

src/Sentry/Platforms/Android/SentrySdk.cs

@@ -65,6 +65,14 @@ private static void InitSentryAndroidSdk(SentryOptions options)
             o.SessionTrackingIntervalMillis = (long)options.AutoSessionTrackingInterval.TotalMilliseconds;
             o.ShutdownTimeoutMillis = (long)options.ShutdownTimeout.TotalMilliseconds;
             var signalHandlerStrategy = options.Native.ExperimentalOptions.SignalHandlerStrategy;
+            if (signalHandlerStrategy == SignalHandlerStrategy.ChainAtStart
+                && Type.GetType("Mono.RuntimeStructs") == null)
+            {
+                options.LogDebug(
+                    "SignalHandlerStrategy.ChainAtStart is not compatible with .NET CoreCLR runtime. " +
+                    "Falling back to SignalHandlerStrategy.Default.");
+                signalHandlerStrategy = SignalHandlerStrategy.Default;
+            }
             if (signalHandlerStrategy == SignalHandlerStrategy.ChainAtStart
                 && System.Environment.Version is { Major: 10, Minor: 0, Build: < 4 })
             {

src/Sentry/buildTransitive/Sentry.props

@@ -5,5 +5,6 @@
     <_SentryTargetFrameworkVersion>$([MSBuild]::GetTargetFrameworkVersion($(TargetFramework)))</_SentryTargetFrameworkVersion>
     <_SentryIsNet8OrGreater>$([MSBuild]::VersionGreaterThanOrEquals($(_SentryTargetFrameworkVersion), 8.0))</_SentryIsNet8OrGreater>
     <_SentryIsNet9OrGreater>$([MSBuild]::VersionGreaterThanOrEquals($(_SentryTargetFrameworkVersion), 9.0))</_SentryIsNet9OrGreater>
+    <_SentryIsNet10OrGreater>$([MSBuild]::VersionGreaterThanOrEquals($(_SentryTargetFrameworkVersion), 10.0))</_SentryIsNet10OrGreater>
   </PropertyGroup>
 </Project>

src/Sentry/buildTransitive/Sentry.targets

@@ -281,6 +281,22 @@
     </ItemGroup>
   </Target>
 
+  <!-- Preload NDK to ensure sentry-native's signal handlers are installed before .NET runtime's.
+       Disabled on Mono until: https://github.com/dotnet/runtime/pull/125835 -->
+  <Target Name="SetAndroidNdkPreload"
+          BeforeTargets="GetAssemblyAttributes"
+          Condition="'$(AndroidApplication)' == 'True'
+            and $([MSBuild]::GetTargetPlatformIdentifier('$(TargetFramework)')) == 'android'
+            and '$(_SentryIsNet10OrGreater)' == 'true'
+            and '$(UseMonoRuntime)' != 'true'">
+    <ItemGroup>
+      <AssemblyAttribute Include="Android.App.MetaData">
+        <_Parameter1>io.sentry.ndk.preload</_Parameter1>
+        <Value>true</Value>
+      </AssemblyAttribute>
+    </ItemGroup>
+  </Target>
+
   <!-- Upload Android ProGuard mapping file to Sentry after the build. -->
   <Target Name="UploadAndroidProGuardMappingFileToSentry" AfterTargets="Build" DependsOnTargets="PrepareSentryCLI"
           Condition="'$(SentryCLI)' != '' and '$(SentryUploadAndroidProGuardMapping)' == 'true' And '$(AndroidProguardMappingFile)' != ''">