dotnet · dellis1972 · Nov 11, 2019 · Oct 29, 2019
diff --git a/Documentation/guides/messages/xa0121.md b/Documentation/guides/messages/xa0121.md
@@ -1,21 +1,21 @@
 ---
-title: Xamarin.Android warning XA0121
-description: XA0121 warning code
-ms.date: 09/19/2019
+title: Xamarin.Android error XA0121
+description: XA0121 error code
+ms.date: 10/30/2019
 ---
-# Xamarin.Android warning XA0121
+# Xamarin.Android error XA0121
 
 ## Issue
 
 The behavior implemented in the
-`<GetAdditionalResourcesFromAssemblies/>` MSBuild task is now
-deprecated.
+`<GetAdditionalResourcesFromAssemblies/>` MSBuild task is no longer
+supported.
 
 This MSBuild task is a precursor to [Xamarin.Build.Download][xbd] that
 enables downloading of Android packages from the internet.
 
 Libraries using any of the following custom assembly-level attributes
-will encounter this warning:
+will encounter this error:
 
 * `IncludeAndroidResourcesFromAttribute`
 * `NativeLibraryReferenceAttribute`
@@ -26,9 +26,8 @@ will encounter this warning:
 The [Xamarin Support Libraries][supportlibs], can be simply updated to
 a newer version on NuGet.
 
-Library authors will need to remove usage of these deprecated
-attributes. Their functionality will be removed in a future version of
-Xamarin.Android.
+Library authors will need to remove usage of these attributes. Their
+functionality was removed in Xamarin.Android 10.2.
 
 [xbd]: https://www.nuget.org/packages/Xamarin.Build.Download
 [supportlibs]: https://github.com/xamarin/AndroidSupportComponents
diff --git a/src/Mono.Android/Android/IncludeAndroidResourcesFromAttribute.cs b/src/Mono.Android/Android/IncludeAndroidResourcesFromAttribute.cs
@@ -3,7 +3,7 @@
 namespace Android {
 
 	[AttributeUsage (AttributeTargets.Assembly, AllowMultiple = true)]
-	[Obsolete ("This attribute is deprecated and will be removed in a future release.")]
+	[Obsolete ("This attribute is not longer supported.", error: true)]
 	public class IncludeAndroidResourcesFromAttribute : ReferenceFilesAttribute
 	{
 		public IncludeAndroidResourcesFromAttribute (string path)

diff --git a/src/Mono.Android/Android/NativeLibraryReferenceAttribute.cs b/src/Mono.Android/Android/NativeLibraryReferenceAttribute.cs
@@ -3,7 +3,7 @@
 namespace Android {
 
 	[AttributeUsage (AttributeTargets.Assembly, AllowMultiple = true)]
-	[Obsolete ("This attribute is deprecated and will be removed in a future release.")]
+	[Obsolete ("This attribute is not longer supported.", error: true)]
 	sealed public class NativeLibraryReferenceAttribute : ReferenceFilesAttribute
 	{
 		public NativeLibraryReferenceAttribute (string filename)

diff --git a/src/Mono.Android/Android/ReferenceFilesAttribute.cs b/src/Mono.Android/Android/ReferenceFilesAttribute.cs
@@ -1,7 +1,7 @@
 using System;
 
 namespace Android {
-	[Obsolete ("This attribute is deprecated and will be removed in a future release.")]
+	[Obsolete ("This attribute is not longer supported.", error: true)]
 	public abstract class ReferenceFilesAttribute : Attribute
 	{
 		internal ReferenceFilesAttribute () {}

diff --git a/src/Mono.Android/Java.Interop/JavaLibraryReferenceAttribute.cs b/src/Mono.Android/Java.Interop/JavaLibraryReferenceAttribute.cs
@@ -3,7 +3,7 @@
 namespace Java.Interop {
 
 	[AttributeUsage (AttributeTargets.Assembly, AllowMultiple = true)]
-	[Obsolete ("This attribute is deprecated and will be removed in a future release.")]
+	[Obsolete ("This attribute is not longer supported.", error: true)]
 	public class JavaLibraryReferenceAttribute : Android.ReferenceFilesAttribute
 	{
 		public JavaLibraryReferenceAttribute (string filename)

diff --git a/src/Xamarin.Android.Build.Tasks/MSBuild/Xamarin/Android/Xamarin.Android.Aapt.targets b/src/Xamarin.Android.Build.Tasks/MSBuild/Xamarin/Android/Xamarin.Android.Aapt.targets
@@ -48,7 +48,6 @@ Copyright (C) 2019  Microsoft Corporation. All rights reserved.
       ExtraArgs="$(AndroidResgenExtraArgs)"
       ToolPath="$(AaptToolPath)"
       ToolExe="$(AaptToolExe)"
-      AdditionalAndroidResourcePaths="@(_AdditonalAndroidResourceCachePaths)"
       ApiLevel="$(_AndroidTargetSdkVersion)"
       AndroidUseLatestPlatformSdk="$(AndroidUseLatestPlatformSdk)"
       ResourceNameCaseMap="$(_AndroidResourceNameCaseMap)"
@@ -81,7 +80,6 @@ Copyright (C) 2019  Microsoft Corporation. All rights reserved.
      AssetDirectory="$(MonoAndroidAssetsDirIntermediate)"
      ToolPath="$(AaptToolPath)"
      ToolExe="$(AaptToolExe)"
-     AdditionalAndroidResourcePaths="@(_AdditonalAndroidResourceCachePaths)"
      ApiLevel="$(_AndroidTargetSdkVersion)"
      AndroidUseLatestPlatformSdk="$(AndroidUseLatestPlatformSdk)"
      ResourceNameCaseMap="$(_AndroidResourceNameCaseMap)"

diff --git a/src/Xamarin.Android.Build.Tasks/MSBuild/Xamarin/Android/Xamarin.Android.Aapt2.targets b/src/Xamarin.Android.Build.Tasks/MSBuild/Xamarin/Android/Xamarin.Android.Aapt2.targets
@@ -50,7 +50,7 @@ Copyright (C) 2011-2012 Xamarin. All rights reserved.
     Condition=" '$(_AndroidUseAapt2)' == 'True' "
   >
   <CollectNonEmptyDirectories
-      Directories="@(LibraryResourceDirectories);@(_AdditonalAndroidResourceCachePaths->'%(Identity)\res')"
+      Directories="@(LibraryResourceDirectories)"
       LibraryProjectIntermediatePath="$(_AndroidLibrayProjectIntermediatePath)"
       StampDirectory="$(_AndroidStampDirectory)">
     <Output TaskParameter="Output" ItemName="_LibraryResourceDirectories" />

diff --git a/src/Xamarin.Android.Build.Tasks/MSBuild/Xamarin/Android/Xamarin.Android.Designer.targets b/src/Xamarin.Android.Build.Tasks/MSBuild/Xamarin/Android/Xamarin.Android.Designer.targets
@@ -19,12 +19,6 @@ Copyright (C) 2016 Xamarin. All rights reserved.
 <Target Name="GetExtraLibraryLocationsForDesigner"
     DependsOnTargets="_SetupDesignTimeBuildForCompile"
     Returns="ExtraJarLocation;ExtraResourceLocation">
-  <ReadAdditionalResourcesFromAssemblyCache
-      Condition="Exists('$(_AndroidResourcePathsCache)')"
-      CacheFile="$(_AndroidResourcePathsCache)">
-    <Output TaskParameter="AdditionalAndroidResourcePaths"  ItemName="_AdditionalAndroidResourcePaths" />
-    <Output TaskParameter="AdditionalJavaLibraryReferences" ItemName="_AdditionalJavaLibraryReferences" />
-  </ReadAdditionalResourcesFromAssemblyCache>
   <ReadLibraryProjectImportsCache
       Condition="Exists('$(_AndroidLibraryProjectImportsCache)')"
       CacheFile="$(_AndroidLibraryProjectImportsCache)">
@@ -41,9 +35,6 @@ Copyright (C) 2016 Xamarin. All rights reserved.
     <ExtraJarLocation Include="@(AndroidJavaLibrary->'%(FullPath)')">
       <Source>AndroidJavaLibrary</Source>
     </ExtraJarLocation>
-    <ExtraResourceLocation Include="@(_AdditionalAndroidResourcePaths->'%(Identity)\res')">
-      <Source>AssemblyCache</Source>
-    </ExtraResourceLocation>
     <ExtraResourceLocation Include="@(_LibraryResourceDirectories)">
       <Source>LibraryImport</Source>
     </ExtraResourceLocation>

diff --git a/src/Xamarin.Android.Build.Tasks/Tasks/FilterAssemblies.cs b/src/Xamarin.Android.Build.Tasks/Tasks/FilterAssemblies.cs
@@ -43,7 +43,7 @@ public override bool RunTask ()
 				using (var pe = new PEReader (File.OpenRead (assemblyItem.ItemSpec))) {
 					var reader = pe.GetMetadataReader ();
 					var assemblyDefinition = reader.GetAssemblyDefinition ();
-					var targetFrameworkIdentifier = assemblyDefinition.GetTargetFrameworkIdentifier (reader);
+					var targetFrameworkIdentifier = GetTargetFrameworkIdentifier (assemblyDefinition, reader);
 					if (string.Compare (targetFrameworkIdentifier, TargetFrameworkIdentifier, StringComparison.OrdinalIgnoreCase) == 0) {
 						output.Add (assemblyItem);
 						continue;
@@ -71,6 +71,40 @@ public override bool RunTask ()
 			return !Log.HasLoggedErrors;
 		}
 
+		string GetTargetFrameworkIdentifier (AssemblyDefinition assembly, MetadataReader reader)
+		{
+			string targetFrameworkIdentifier = null;
+			foreach (var handle in assembly.GetCustomAttributes ()) {
+				var attribute = reader.GetCustomAttribute (handle);
+				var name = reader.GetCustomAttributeFullName (attribute);
+				switch (name) {
+					case "System.Runtime.Versioning.TargetFrameworkAttribute":
+						var arguments = attribute.GetCustomAttributeArguments ();
+						foreach (var p in arguments.FixedArguments) {
+							// Of the form "MonoAndroid,Version=v8.1"
+							var value = p.Value?.ToString ();
+							if (!string.IsNullOrEmpty (value)) {
+								int commaIndex = value.IndexOf (",", StringComparison.Ordinal);
+								if (commaIndex != -1) {
+									targetFrameworkIdentifier = value.Substring (0, commaIndex);
+									break;
+								}
+							}
+						}
+						break;
+					case "Android.IncludeAndroidResourcesFromAttribute":
+					case "Android.NativeLibraryReferenceAttribute":
+					case "Java.Interop.JavaLibraryReferenceAttribute":
+						Log.LogCodedError ("XA0121",
+							$"Assembly '{reader.GetString (assembly.Name)}' is using '[assembly: {name}]', which is no longer supported. Use a newer version of this NuGet package or notify the library author.");
+						break;
+					default:
+						break;
+				}
+			}
+			return targetFrameworkIdentifier;
+		}
+
 		bool HasReference (MetadataReader reader)
 		{
 			foreach (var handle in reader.AssemblyReferences) {