Fix R8 JNI seed configuration inputs

Build the seed R8 configuration from user and library consumer rules instead of final generated configuration, whose baseline native-method rule pins ACW names.

Co-authored-by: Copilot App <223556219+Copilot@users.noreply.github.com>

Author: simonrozsival

src/Xamarin.Android.Build.Tasks/MSBuild/Xamarin/Android/Xamarin.Android.Aapt2.targets

@@ -245,7 +245,9 @@ Copyright (C) 2011-2012 Xamarin. All rights reserved.
       ProguardRuleOutput="$(_Aapt2ProguardRules)"
   />
   <ItemGroup Condition=" '$(_Aapt2ProguardRules)' != '' And Exists('$(_Aapt2ProguardRules)') ">
-    <ProguardConfiguration Include="$(_Aapt2ProguardRules)" />
+    <ProguardConfiguration Include="$(_Aapt2ProguardRules)">
+      <AndroidGeneratedProguardConfiguration>true</AndroidGeneratedProguardConfiguration>
+    </ProguardConfiguration>
     <FileWrites Include="$(_Aapt2ProguardRules)" />
     <FileWrites Include="$(IntermediateOutputPath)android\*\aapt_rules.txt" />
   </ItemGroup>

src/Xamarin.Android.Build.Tasks/Microsoft.Android.Sdk/targets/Microsoft.Android.Sdk.TypeMap.Trimmable.targets

@@ -122,11 +122,16 @@
 
   <Target Name="_AndroidGenerateR8JniSeedMappingInputs"
       Condition=" '$(_AndroidEnableR8JniNameRewriting)' == 'true' "
-      DependsOnTargets="_AndroidCompileR8JniSeedJava;_CalculateProguardConfigurationFiles">
+      DependsOnTargets="_AndroidCompileR8JniSeedJava">
     <ItemGroup>
       <_AndroidR8JniSeedClassFile Include="$(_AndroidR8JniSeedJavaClassDirectory)**\*.class" />
-      <_AndroidR8JniSeedProguardConfiguration Include="@(_ProguardConfiguration)" />
-      <_AndroidR8JniSeedProguardConfiguration Remove="$(IntermediateOutputPath)proguard\proguard_xamarin.cfg;$(_ProguardProjectConfiguration);$(IntermediateOutputPath)proguard\proguard_project_primary.cfg;$(IntermediateOutputPath)aapt_rules.txt" />
+      <!-- Seed R8 already disables tree shaking and optimization. Do not use proguard-android.txt:
+           its native-method rule preserves ACW names. Start from source items so generated ACW,
+           reachability, primary, Xamarin, and aapt configurations cannot leak into this pass. -->
+      <_AndroidR8JniSeedProguardConfiguration Include="$(ProguardConfigFiles)" Condition=" '$(ProguardConfigFiles)' != '' " />
+      <_AndroidR8JniSeedProguardConfiguration
+          Include="@(ProguardConfiguration)"
+          Condition=" '$(ProguardConfigFiles)' == '' and '%(ProguardConfiguration.AndroidGeneratedProguardConfiguration)' != 'true' " />
       <_AndroidR8JniSeedMapDiagnostics Condition=" '$(AndroidR8IgnoreWarnings)' == 'true' " Include="warning" To="info" />
     </ItemGroup>
   </Target>

src/Xamarin.Android.Build.Tasks/Tests/Xamarin.Android.Build.Tests/Tasks/R8Tests.cs

@@ -65,8 +65,12 @@ public void GenerateSeedMappingAllowsAcwObfuscation ()
 				string applicationConfiguration = Path.Combine (path, "acw-keep.cfg");
 				string commonConfiguration = Path.Combine (path, "xamarin.cfg");
 				string customConfiguration = Path.Combine (path, "custom.cfg");
+				string aarConfiguration = Path.Combine (path, "aar-proguard.txt");
 				File.WriteAllText (acwMap, "Managed.Peer;com.example.Peer");
 				File.WriteAllText (customConfiguration, "-dontwarn com.example.**");
+				File.WriteAllText (aarConfiguration, "-dontwarn com.example.library.**");
+				var aarConfigurationItem = new TaskItem (aarConfiguration);
+				aarConfigurationItem.SetMetadata ("OriginalFile", Path.Combine (path, "library.aar"));
 
 				var task = new R8TestTask {
 					BuildEngine = new MockBuildEngine (TestContext.Out),
@@ -77,7 +81,7 @@ public void GenerateSeedMappingAllowsAcwObfuscation ()
 					ProguardGeneratedApplicationConfiguration = applicationConfiguration,
 					ProguardCommonXamarinConfiguration = commonConfiguration,
 					ProguardMappingFileOutput = Path.Combine (path, "mapping.txt"),
-					ProguardConfigurationFiles = new ITaskItem [] { new TaskItem (customConfiguration) },
+					ProguardConfigurationFiles = new ITaskItem [] { new TaskItem (customConfiguration), aarConfigurationItem },
 					GenerateSeedMapping = true,
 					EnableObfuscation = true,
 					IgnoreWarnings = true,
@@ -94,6 +98,7 @@ public void GenerateSeedMappingAllowsAcwObfuscation ()
 				string configuration = string.Join (Environment.NewLine, configurationFiles.Select (File.ReadAllText));
 
 				Assert.That (configurationFiles, Does.Contain (customConfiguration), "Seed R8 should honor user ProGuard rules.");
+				Assert.That (configurationFiles, Does.Contain (aarConfiguration), "Seed R8 should honor AAR consumer rules.");
 				Assert.That (configurationFiles, Does.Contain (commonConfiguration), "Seed R8 should honor runtime keep rules.");
 				Assert.That (configurationFiles, Does.Not.Contain (applicationConfiguration), "Seed R8 must not pass the ACW keep configuration.");
 				FileAssert.DoesNotExist (applicationConfiguration, "Seed R8 must not generate obfuscation-blocking ACW keep rules.");

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

@@ -333,6 +333,9 @@ public R8JniLibraryPeer () { }
 				},
 			};
 			library.SetRuntime (runtime);
+			library.OtherBuildItems.Add (new AndroidItem.ProguardConfiguration ("proguard.txt") {
+				TextContent = () => "-dontwarn com.example.library.**",
+			});
 
 			var app = new XamarinAndroidApplicationProject {
 				IsRelease = true,
@@ -347,6 +350,28 @@ public R8JniLibraryPeer () { }
 			app.OtherBuildItems.Add (new AndroidItem.ProguardConfiguration ("r8-jni-rules.pro") {
 				TextContent = () => proguardRule,
 			});
+			app.OtherBuildItems.Add (new AndroidItem.ProguardConfiguration ("generated-acw-keep.cfg") {
+				TextContent = () => $"-keep class {libraryJavaName.Replace ('/', '.')} {{ *; }}",
+				Metadata = {
+					{ "AndroidGeneratedProguardConfiguration", "true" },
+				},
+			});
+			app.Imports.Add (new Import ("CaptureR8JniSeedConfiguration.targets") {
+				TextContent = () => """
+					<Project>
+					  <Target Name="_CaptureR8JniSeedConfiguration"
+					      AfterTargets="_AndroidGenerateR8JniSeedMappingInputs"
+					      BeforeTargets="_AndroidGenerateR8JniSeedMapping">
+					    <MakeDir Directories="$(_AndroidR8JniSeedDirectory)" />
+					    <WriteLinesToFile
+					        File="$(_AndroidR8JniSeedDirectory)configuration-items.txt"
+					        Lines="@(_AndroidR8JniSeedProguardConfiguration)"
+					        Overwrite="true"
+					        WriteOnlyWhenDifferent="true" />
+					  </Target>
+					</Project>
+					""",
+			});
 
 			string testDirectory = Path.Combine ("temp", $"R8JniNameRewritingReferences_{runtime}_{Guid.NewGuid ():N}");
 			using var libraryBuilder = CreateDllBuilder (Path.Combine (testDirectory, library.ProjectName));
@@ -357,8 +382,14 @@ public R8JniLibraryPeer () { }
 			var projectDirectory = Path.Combine (Root, appBuilder.ProjectDirectory);
 			var seedMapping = FindSingleFile (projectDirectory, "mapping.txt", path => path.Contains ("r8-jni-seed", StringComparison.Ordinal));
 			var rewriteManifest = FindSingleFile (projectDirectory, "r8-jni-rewrite-manifest.txt");
-			StringAssert.Contains ($"{libraryJavaName.Replace ('/', '.')} ->", File.ReadAllText (seedMapping));
+			var seedConfigurationItems = File.ReadAllLines (FindSingleFile (projectDirectory, "configuration-items.txt"));
+			AssertR8MappingRenamesClass (seedMapping, libraryJavaName);
 			StringAssert.Contains ($"C\t{libraryJavaName}", File.ReadAllText (rewriteManifest));
+			Assert.That (seedConfigurationItems, Has.Some.EndsWith ("r8-jni-rules.pro"), "Seed R8 should receive user-authored rules.");
+			Assert.That (seedConfigurationItems, Has.Some.EndsWith ("proguard.txt"), "Seed R8 should receive AAR consumer rules.");
+			Assert.IsFalse (seedConfigurationItems.Any (path =>
+				new [] { "proguard-android.txt", "proguard_xamarin.cfg", "proguard_project_references.cfg", "proguard_project_primary.cfg", "aapt_rules.txt", "generated-acw-keep.cfg" }.Contains (Path.GetFileName (path), StringComparer.Ordinal)),
+				"Seed R8 should not receive generated or baseline configurations that pin managed peers.");
 
 			proguardRule = "-dontwarn com.example.UnusedTwo";
 			app.Touch ("r8-jni-rules.pro");