[Xamarin.Android.Build.Tasks] Add XA1031 error for `AndroidHttpClient…

…HandlerType`

Fixes dotnet#7326

We should check the value of the `AndroidHttpClientHandlerType` property
during the build process. This property can have a number of
different values depending on what version of Xamarin.Android is being
used.

Under Classic a valid value is `Xamarin.Android.Net.AndroidClientHandler`,
however under .NET 6+ the valid values are

- `Xamarin.Android.Net.AndroidMessageHandler`.
- `System.Net.Http.SocketsHttpHandler, System.Net.Http`.

We should raise an error if the user is using an invalid
value.

Documentation/guides/messages/README.md

@@ -130,6 +130,7 @@ or 'Help->Report a Problem' in Visual Studio for Mac.
 + [XA1027](xa1027.md): The 'EnableProguard' MSBuild property is set to 'true' and the 'AndroidLinkTool' MSBuild property is empty, so 'AndroidLinkTool' will default to 'proguard'.
 + [XA1028](xa1028.md): The 'AndroidEnableProguard' MSBuild property is set to 'true' and the 'AndroidLinkTool' MSBuild property is empty, so 'AndroidLinkTool' will default to 'proguard'.
 + [XA1029](xa1029.md): The 'AotAssemblies' MSBuild property is deprecated. Edit the project file in a text editor to remove this property, and use the 'RunAOTCompilation' MSBuild property instead.
++ [XA1031](xa1031.md): The 'AndroidHttpClientHandlerType' has an invalid value.
 
 ## XA2xxx: Linker
 

Documentation/guides/messages/xa1031.md

@@ -0,0 +1,20 @@
+---
+title: Xamarin.Android error XA1031
+description: XA1031 error code
+ms.date: 10/10/2022
+---
+# Xamarin.Android error XA1031
+
+## Example messages
+
+```
+The 'AndroidHttpClientHandlerType' has an invalid value of 'xxx' please check your project settings.
+```
+
+## Solution
+
+Open your project settings in Visual Studio and check that the
+'AndroidHttpClientHandlerType' has a valid value. Alternatively
+you can edit your csproj directly and change the 'AndroidHttpClientHandlerType'.
+
+Valid values can be found at `~/android/deploy-test/building-apps/build-properties.md#AndroidHttpClientHandlerType`.

src/Xamarin.Android.Build.Tasks/Microsoft.Android.Sdk/targets/Microsoft.Android.Sdk.BuildOrder.targets

@@ -14,6 +14,7 @@ projects, these properties are set in Xamarin.Android.Legacy.targets.
   <PropertyGroup Condition=" '$(AndroidApplication)' == 'True' ">
     <BuildDependsOn>
       _ValidateLinkMode;
+      _CheckAndroidHttpClientHandlerType;
       _CheckNonIdealConfigurations;
       _SetupMSBuildAllProjects;
       _SetupDesignTimeBuildForBuild;

src/Xamarin.Android.Build.Tasks/Properties/Resources.resx

@@ -470,6 +470,11 @@ In this message, the term "binding" means a piece of generated code that makes i
     <value>The 'RunAOTCompilation' MSBuild property is only supported when trimming is enabled. Edit the project file in a text editor to set 'PublishTrimmed' to 'true' for this build configuration.</value>
     <comment>The following are literal names and should not be translated: 'RunAOTCompilation', 'PublishTrimmed'</comment>
   </data>
+  <data name="XA1031" xml:space="preserve">
+    <value>The 'AndroidHttpClientHandlerType' has an invalid value of '{0}' please check your project settings.</value>
+    <comment>The following are literal names and should not be translated: 'AndroidHttpClientHandlerType',
+{0} - The value of the property.</comment>
+  </data>
   <data name="XA2000" xml:space="preserve">
     <value>Use of AppDomain.CreateDomain() detected in assembly: {0}. .NET 6 and higher will only support a single AppDomain, so this API will no longer be available in Xamarin.Android once .NET 6 is released.</value>
     <comment>The following are literal names and should not be translated: AppDomain.CreateDomain(), AppDomain

src/Xamarin.Android.Build.Tasks/Tests/Xamarin.Android.Build.Tests/EnvironmentContentTests.cs

@@ -194,6 +194,20 @@ public void CheckBuildIdIsUnique ([Values ("apk", "aab")] string packageFormat)
 			}
 		}
 
+		[Test]
+		public void CheckForInvalidHttpClientHandlerType ()
+		{
+			var proj = new XamarinAndroidApplicationProject () {
+				IsRelease = true,
+			};
+			using (var b = CreateApkBuilder ()) {
+				b.ThrowOnBuildFailure = false;
+				proj.SetProperty ("AndroidHttpClientHandlerType", "invalidvalue");
+				Assert.IsFalse (b.Build (proj), "Build should have succeeded.");
+				Assert.IsTrue (StringAssertEx.ContainsText (b.LastBuildOutput, "XA1031"), "Output should contain XA1031");
+			}
+		}
+
 		[Test]
 		public void CheckHttpClientHandlerType ()
 		{

src/Xamarin.Android.Build.Tasks/Xamarin.Android.Common.targets

@@ -483,6 +483,20 @@ Copyright (C) 2011-2012 Xamarin. All rights reserved.
   </ItemGroup>
 </Target>
 
+<Target Name="_CheckAndroidHttpClientHandlerType"
+    Condition=" '$(AndroidHttpClientHandlerType)' != ''">
+  <PropertyGroup>
+    <ValidAndroidHttpClientHandlerTypes Condition="'$(UsingAndroidNETSdk)' != 'true'">Xamarin.Android.Net.AndroidClientHandler</ValidAndroidHttpClientHandlerTypes>
+    <ValidAndroidHttpClientHandlerTypes Condition="'$(UsingAndroidNETSdk)' == 'true'">Xamarin.Android.Net.AndroidMessageHandler</ValidAndroidHttpClientHandlerTypes>
+    <ValidAndroidHttpClientHandlerTypes Condition="'$(UsingAndroidNETSdk)' == 'true'">$(ValidAndroidHttpClientHandlerTypes);System.Net.Http.SocketsHttpHandler, System.Net.Http</ValidAndroidHttpClientHandlerTypes>
+  </PropertyGroup>
+  <AndroidError Code="XA1031"
+      ResourceName="XA1031"
+      FormatArguments="$(AndroidHttpClientHandlerType)"
+      Condition=" !($(ValidAndroidHttpClientHandlerTypes.Contains ('$(AndroidHttpClientHandlerType)')))"
+  />
+</Target>
+
 <Target Name="_CheckNonIdealConfigurations">
   <AndroidWarning Code="XA0119"
       ResourceName="XA0119_AOT"

src/Xamarin.Android.Build.Tasks/Xamarin.Android.Legacy.targets

@@ -27,6 +27,7 @@ projects. .NET 5 projects will not import this file.
   <PropertyGroup Condition=" '$(AndroidApplication)' == 'True' And '$(_AndroidIsBindingProject)' != 'True' ">
     <BuildDependsOn>
       _ValidateLinkMode;
+      _CheckAndroidHttpClientHandlerType;
       _CheckNonIdealConfigurations;
       _SetupMSBuildAllProjects;
       _SetupDesignTimeBuildForBuild;