From 953ff597cf5989f4b0485907ccf8799e82b6c00a Mon Sep 17 00:00:00 2001
From: Matous Kozak <matouskozak@seznam.cz>
Date: Tue, 19 Nov 2024 15:46:24 +0100
Subject: [PATCH 1/4] enable DefaultValueAttributeSupport

---
 .../targets/Microsoft.Android.Sdk.DefaultProperties.targets     | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/src/Xamarin.Android.Build.Tasks/Microsoft.Android.Sdk/targets/Microsoft.Android.Sdk.DefaultProperties.targets b/src/Xamarin.Android.Build.Tasks/Microsoft.Android.Sdk/targets/Microsoft.Android.Sdk.DefaultProperties.targets
index 7e95621a2d2..f4b2c338709 100644
--- a/src/Xamarin.Android.Build.Tasks/Microsoft.Android.Sdk/targets/Microsoft.Android.Sdk.DefaultProperties.targets
+++ b/src/Xamarin.Android.Build.Tasks/Microsoft.Android.Sdk/targets/Microsoft.Android.Sdk.DefaultProperties.targets
@@ -114,6 +114,8 @@
     <UseNativeHttpHandler Condition="'$(UseNativeHttpHandler)' == ''">true</UseNativeHttpHandler>
     <BuiltInComInteropSupport Condition="'$(BuiltInComInteropSupport)' == ''">false</BuiltInComInteropSupport>
     <JsonSerializerIsReflectionEnabledByDefault Condition="'$(JsonSerializerIsReflectionEnabledByDefault)' == '' and '$(TrimMode)' == 'partial'">true</JsonSerializerIsReflectionEnabledByDefault>
+    <!-- Set to disable throwing behavior, see: https://github.com/dotnet/runtime/issues/109724 -->
+    <_DefaultValueAttributeSupport Condition="'$(_DefaultValueAttributeSupport)' == '' and '$(TrimMode)' == 'partial'">true</_DefaultValueAttributeSupport>
     <MetricsSupport Condition="'$(MetricsSupport)' == ''">false</MetricsSupport>
     <AndroidAvoidEmitForPerformance Condition="'$(AndroidAvoidEmitForPerformance)' == ''">$(AvoidEmitForPerformance)</AndroidAvoidEmitForPerformance>
     <AndroidAvoidEmitForPerformance Condition="'$(AndroidAvoidEmitForPerformance)' == ''">true</AndroidAvoidEmitForPerformance>

From 14cfd74a6f924109abf13894e5106db44ada51a5 Mon Sep 17 00:00:00 2001
From: Matous Kozak <matouskozak@seznam.cz>
Date: Tue, 19 Nov 2024 17:54:57 +0100
Subject: [PATCH 2/4] XmlSerializer test for DefaultValueAttributes

---
 .../System.Xml/XmlSerializer.cs               | 23 +++++++++++++++++++
 1 file changed, 23 insertions(+)
 create mode 100644 tests/Mono.Android-Tests/System.Xml/XmlSerializer.cs

diff --git a/tests/Mono.Android-Tests/System.Xml/XmlSerializer.cs b/tests/Mono.Android-Tests/System.Xml/XmlSerializer.cs
new file mode 100644
index 00000000000..61cb3ce56a9
--- /dev/null
+++ b/tests/Mono.Android-Tests/System.Xml/XmlSerializer.cs
@@ -0,0 +1,23 @@
+using System.Xml.Serialization;
+using System.ComponentModel;
+
+using NUnit.Framework;
+
+namespace System.XmlTests {
+    public class C {
+        [DefaultValue(typeof(C), "c")]
+        public Type? T { get; }
+    }
+    
+    [TestFixture]
+    public class XmlSerializerTest {
+
+        [Test]
+        public void TrimmingDefaultValueAttribute ()
+        {
+            // Context: https://github.com/dotnet/runtime/issues/109724
+            var s = new XmlSerializer(typeof(C));
+            _ = new C().T; // Prevent C.T from being removed by trimming
+        }
+    }
+}

From 4c97e0266bc1d08ec90a4225abba38c1062e862d Mon Sep 17 00:00:00 2001
From: Jonathan Peppers <jonathan.peppers@microsoft.com>
Date: Tue, 19 Nov 2024 11:24:02 -0600
Subject: [PATCH 3/4] Update Mono.Android-Test.Shared.projitems

---
 tests/Mono.Android-Tests/Mono.Android-Test.Shared.projitems | 1 +
 1 file changed, 1 insertion(+)

diff --git a/tests/Mono.Android-Tests/Mono.Android-Test.Shared.projitems b/tests/Mono.Android-Tests/Mono.Android-Test.Shared.projitems
index 0b1ccf1d595..a13accab96d 100644
--- a/tests/Mono.Android-Tests/Mono.Android-Test.Shared.projitems
+++ b/tests/Mono.Android-Tests/Mono.Android-Test.Shared.projitems
@@ -48,6 +48,7 @@
     <Compile Include="$(MSBuildThisFileDirectory)System.Text\EncodingTests.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)System.Text.Json\JsonSerializerTest.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)System.Threading\InterlockedTest.cs" />
+    <Compile Include="$(MSBuildThisFileDirectory)System.Xml\XmlSerializer.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)Java.Interop\JavaObjectExtensionsTests.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)Xamarin.Android.Net\AndroidClientHandlerTests.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)Xamarin.Android.Net\AndroidMessageHandlerTests.cs" />

From a50c10c62e9f055307dd85dd059ded6525001679 Mon Sep 17 00:00:00 2001
From: Jonathan Peppers <jonathan.peppers@microsoft.com>
Date: Tue, 19 Nov 2024 14:11:03 -0600
Subject: [PATCH 4/4] Add `-p:TestsFlavor=TrimModePartial`

---
 build-tools/automation/azure-pipelines.yaml            | 10 ++++++++++
 .../Mono.Android.NET-Tests.csproj                      |  3 ++-
 2 files changed, 12 insertions(+), 1 deletion(-)

diff --git a/build-tools/automation/azure-pipelines.yaml b/build-tools/automation/azure-pipelines.yaml
index ed8514e4c9c..0796a5fb81e 100644
--- a/build-tools/automation/azure-pipelines.yaml
+++ b/build-tools/automation/azure-pipelines.yaml
@@ -203,6 +203,16 @@ extends:
             artifactSource: bin/Test$(XA.Build.Configuration)/$(DotNetTargetFramework)-android/Mono.Android.NET_Tests-Signed.aab
             artifactFolder: $(DotNetTargetFramework)-NoAot
 
+        - template: /build-tools/automation/yaml-templates/apk-instrumentation.yaml@self
+          parameters:
+            configuration: $(XA.Build.Configuration)
+            testName: Mono.Android.NET_Tests-TrimModePartial
+            project: tests/Mono.Android-Tests/Runtime-Microsoft.Android.Sdk/Mono.Android.NET-Tests.csproj
+            testResultsFiles: TestResult-Mono.Android.NET_Tests-$(XA.Build.Configuration)TrimModePartial.xml
+            extraBuildArgs: -p:TestsFlavor=TrimModePartial -p:TrimMode=partial
+            artifactSource: bin/Test$(XA.Build.Configuration)/$(DotNetTargetFramework)-android/Mono.Android.NET_Tests-Signed.aab
+            artifactFolder: $(DotNetTargetFramework)-TrimModePartial
+
         - template: /build-tools/automation/yaml-templates/apk-instrumentation.yaml@self
           parameters:
             configuration: $(XA.Build.Configuration)
diff --git a/tests/Mono.Android-Tests/Runtime-Microsoft.Android.Sdk/Mono.Android.NET-Tests.csproj b/tests/Mono.Android-Tests/Runtime-Microsoft.Android.Sdk/Mono.Android.NET-Tests.csproj
index d8affbe62dd..ad1e6e8e7fa 100644
--- a/tests/Mono.Android-Tests/Runtime-Microsoft.Android.Sdk/Mono.Android.NET-Tests.csproj
+++ b/tests/Mono.Android-Tests/Runtime-Microsoft.Android.Sdk/Mono.Android.NET-Tests.csproj
@@ -38,7 +38,8 @@
     <AndroidLinkTool Condition=" '$(AndroidLinkTool)' == '' ">r8</AndroidLinkTool>
     <TrimMode Condition=" '$(TrimMode)' == '' ">full</TrimMode>
     <!-- Trimmer switches required for tests -->
-    <JsonSerializerIsReflectionEnabledByDefault>true</JsonSerializerIsReflectionEnabledByDefault>
+    <JsonSerializerIsReflectionEnabledByDefault Condition="'$(TrimMode)' == 'full'">true</JsonSerializerIsReflectionEnabledByDefault>
+    <_DefaultValueAttributeSupport Condition="'$(TrimMode)' == 'full'">true</_DefaultValueAttributeSupport>
   </PropertyGroup>
 
   <ItemGroup>