[Xamarin.Android.Build.Tasks] Feature for excluding Kotlin-related files from apps

Documentation/guides/building-apps/build-items.md

@@ -204,6 +204,26 @@ used to specify the ABI that the library targets. Thus, if you add
 </ItemGroup>
 ```
 
+## AndroidPackagingOptionsExclude
+
+A set if RegEx compatible items which will allow for items to be
+excluded from the final package. The default values are as follows
+
+```
+<ItemGroup>
+	<AndroidPackagingOptionsExclude Include="DebugProbesKt.bin" />
+	<AndroidPackagingOptionsExclude Include="%2A.kotlin_%2A" />
+</ItemGroup>
+```
+
+NOTE: The Items MUST use URL encoding for characters like `*`. This
+is so MSBuild does not try to interpret them as file wildcards.
+
+NOTE: `*` will be replaced in the `BuildApk` task with the RegEx
+`(.)` to match all characters.
+
+Added in Xamarin.Android XX.X.
+
 ## AndroidResource
 
 All files with an *AndroidResource* build action are compiled into

src/Xamarin.Android.Build.Tasks/Tasks/BuildApk.cs

@@ -74,6 +74,8 @@ public class BuildApk : AndroidTask
 
 		public string[] DoNotPackageJavaLibraries { get; set; }
 
+		public string [] ExcludeFiles { get; set; }
+
 		public string Debug { get; set; }
 
 		public string AndroidSequencePointsMode { get; set; }
@@ -122,6 +124,8 @@ protected virtual void FixupArchive (ZipArchiveEx zip) { }
 
 		List<string> existingEntries = new List<string> ();
 
+		List<Regex> excludePatterns = new List<Regex> ();
+
 		void ExecuteWithAbi (string [] supportedAbis, string apkInputPath, string apkOutputPath, bool debug, bool compress, IDictionary<string, CompressedAssemblyInfo> compressedAssembliesInfo, string assemblyStoreApkName)
 		{
 			ArchiveFileList files = new ArchiveFileList ();
@@ -248,6 +252,13 @@ void ExecuteWithAbi (string [] supportedAbis, string apkInputPath, string apkOut
 								Log.LogDebugMessage ($"Skipping {path} as the archive file is up to date.");
 								continue;
 							}
+							// check for ignored items
+							foreach (var pattern in excludePatterns) {
+								if(pattern.IsMatch (path)) {
+									Log.LogDebugMessage ($"Ignoring jar entry '{name}' from '{Path.GetFileName (jarFile)}'. Filename matched the exclude pattern '{pattern}'.");
+									continue;
+								}
+							}
 							if (string.Compare (Path.GetFileName (name), "AndroidManifest.xml", StringComparison.OrdinalIgnoreCase) == 0) {
 								Log.LogDebugMessage ("Ignoring jar entry {0} from {1}: the same file already exists in the apk", name, Path.GetFileName (jarFile));
 								continue;
@@ -293,6 +304,10 @@ public override bool RunTask ()
 
 			existingEntries.Clear ();
 
+			foreach (var pattern in ExcludeFiles) {
+				excludePatterns.Add (new Regex (pattern.Replace ("*", "(.)"), RegexOptions.IgnoreCase | RegexOptions.Compiled));
+			}
+
 			bool debug = _Debug;
 			bool compress = !debug && EnableCompression;
 			IDictionary<string, CompressedAssemblyInfo> compressedAssembliesInfo = null;

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

@@ -915,6 +915,26 @@ public class Test
 			}
 		}
 
+		[Test]
+		public void CheckExcludedFilesAreMissing ()
+		{
+
+			var proj = new XamarinAndroidApplicationProject () {
+				IsRelease = true,
+			};
+			proj.PackageReferences.Add (KnownPackages.Xamarin_Kotlin_StdLib_Common);
+			using (var b = CreateApkBuilder ()) {
+				Assert.IsTrue (b.Build (proj), "Build should have succeeded.");
+				var apk = Path.Combine (Root, b.ProjectDirectory,
+					proj.OutputPath, $"{proj.PackageName}-Signed.apk");
+				string expected = $"Ignoring jar entry 'kotlin/Error.kotlin_metadata'";
+				Assert.IsTrue (b.LastBuildOutput.ContainsText (expected), $"Error.kotlin_metadata should have been ignored.");
+				using (var zip = ZipHelper.OpenZip (apk)) {
+					Assert.IsFalse (zip.ContainsEntry ("Error.kotlin_metadata"), "Error.kotlin_metadata should have been ignored.");
+				}
+			}
+		}
+
 		[Test]
 		public void ExtractNativeLibsTrue ()
 		{

src/Xamarin.Android.Build.Tasks/Tests/Xamarin.ProjectTools/Android/KnownPackages.cs

@@ -499,6 +499,10 @@ public static class KnownPackages
 			Id = "Xamarin.GooglePlayServices.Maps",
 			Version = "117.0.1.2",
 		};
+		public static Package Xamarin_Kotlin_StdLib_Common = new Package {
+			Id = "Xamarin.Kotlin.Stdlib.Common",
+			Version = "1.6.20.1"
+		};
 		public static Package Acr_UserDialogs = new Package {
 			Id = "Acr.UserDialogs",
 			Version = "6.5.1",

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

@@ -351,6 +351,11 @@ Copyright (C) 2011-2012 Xamarin. All rights reserved.
 	</AllowedReferenceRelatedFileExtensions>
 </PropertyGroup>
 
+<ItemGroup>
+	<AndroidPackagingOptionsExclude Include="DebugProbesKt.bin" />
+	<AndroidPackagingOptionsExclude Include="%2A.kotlin_%2A" />
+</ItemGroup>
+
 <!--
 *******************************************
           Imports
@@ -2063,6 +2068,7 @@ because xbuild doesn't support framework reference assemblies.
     IncludeWrapSh="$(AndroidIncludeWrapSh)"
     CheckedBuild="$(_AndroidCheckedBuild)"
     RuntimeConfigBinFilePath="$(_BinaryRuntimeConfigPath)"
+    ExcludeFiles="@(AndroidPackagingOptionsExclude)"
     UseAssemblyStore="$(AndroidUseAssemblyStore)">
     <Output TaskParameter="OutputFiles" ItemName="ApkFiles" />
   </BuildApk>
@@ -2096,6 +2102,7 @@ because xbuild doesn't support framework reference assemblies.
       IncludeWrapSh="$(AndroidIncludeWrapSh)"
       CheckedBuild="$(_AndroidCheckedBuild)"
       RuntimeConfigBinFilePath="$(_BinaryRuntimeConfigPath)"
+      ExcludeFiles="@(AndroidPackagingOptionsExclude)"
       UseAssemblyStore="$(AndroidUseAssemblyStore)">
     <Output TaskParameter="OutputFiles" ItemName="BaseZipFile" />
   </BuildBaseAppBundle>