[Xamarin.Android.Build.Tasks] warn XA0149 on legacy __AndroidEnvironment__ resources

Documentation/docs-mobile/messages/index.md

@@ -111,6 +111,7 @@ or 'Help->Report a Problem' in Visual Studio for Mac.
 + [XA0146](xa0146.md): Attempt to check whether '{0}' is a correctly aligned ELF file failed with exception, ignoring alignment check for the file.
 + [XA0147](xa0147.md): Attempt to check whether '{0}' is a valid ELF file failed with exception, ignoring AOT check for the file.
 + [XA0148](xa0148.md): Attempt to check whether '{0}' is a valid ELF file failed with exception, ignoring symbol '{1}@{2}' check for the file.
++ [XA0149](xa0149.md): Ignoring legacy Xamarin.Android environment file '{0}' from NuGet package '{1}' version '{2}' in assembly '{3}'. Environment files from Xamarin.Android class libraries are not supported in .NET for Android.
 
 ## XA1xxx: Project related
 

Documentation/docs-mobile/messages/xa0149.md

@@ -0,0 +1,45 @@
+---
+title: .NET for Android warning XA0149
+description: XA0149 warning code
+ms.date: 06/18/2026
+f1_keywords:
+ - "XA0149"
+---
+
+# .NET for Android warning XA0149
+
+## Example messages
+
+> warning XA0149: Ignoring legacy Xamarin.Android environment file '__AndroidEnvironment__abc123' from NuGet package 'Some.Old.Package' version '1.2.3' in assembly '/path/to/Some.Old.Package.dll'. Environment files from Xamarin.Android class libraries are not supported in .NET for Android. Use a newer version of this NuGet package or notify the library author.
+
+> warning XA0149: Ignoring legacy Xamarin.Android environment file '__AndroidEnvironment__abc123' in assembly '/path/to/SomeLibrary.dll'. Environment files from Xamarin.Android class libraries are not supported in .NET for Android. Use a newer version of this assembly or notify the library author.
+
+## Issue
+
+A referenced assembly (typically from an older Xamarin.Android class
+library or a NuGet package targeting `MonoAndroid`) contains an embedded
+`__AndroidEnvironment__*` resource. .NET for Android does not consume
+environment files contributed by class libraries via this legacy
+mechanism, so the file is being ignored.
+
+This is closely related to the
+[NU1703](https://learn.microsoft.com/nuget/reference/errors-and-warnings/nu1703)
+warning that NuGet emits for packages still targeting the deprecated
+`MonoAndroid` framework.
+
+## Solution
+
+Update to a version of the NuGet package or library that targets
+`net-android` (.NET for Android). If you maintain the library, rebuild
+it as a .NET for Android class library so that any environment variables
+are produced in the supported `.net/env/` AAR layout.
+
+If the environment variables are required by your application, declare
+them directly in your app project using an `@(AndroidEnvironment)`
+item:
+
+```xml
+<ItemGroup>
+ <AndroidEnvironment Include="env.txt" />
+</ItemGroup>
+```

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

@@ -1193,6 +1193,20 @@ To use a custom JDK path for a command line build, set the 'JavaSdkDirectory' MS
  <comment>{0} - The file path.
 {1} - The symbol name.
 {2} - The section name.</comment>
+ </data>
+ <data name="XA0149" xml:space="preserve">
+ <value>Ignoring legacy Xamarin.Android environment file '{0}' from NuGet package '{1}' version '{2}' in assembly '{3}'. Environment files from Xamarin.Android class libraries are not supported in .NET for Android. Use a newer version of this NuGet package or notify the library author.</value>
+ <comment>The following are literal names and should not be translated: Xamarin.Android, .NET for Android, NuGet.
+{0} - The name of the embedded environment resource (such as __AndroidEnvironment__abc123).
+{1} - The NuGet package id.
+{2} - The NuGet package version.
+{3} - The full path to the assembly that contains the environment resource.</comment>
+ </data>
+ <data name="XA0149_Assembly" xml:space="preserve">
+ <value>Ignoring legacy Xamarin.Android environment file '{0}' in assembly '{1}'. Environment files from Xamarin.Android class libraries are not supported in .NET for Android. Use a newer version of this assembly or notify the library author.</value>
+ <comment>The following are literal names and should not be translated: Xamarin.Android, .NET for Android.
+{0} - The name of the embedded environment resource (such as __AndroidEnvironment__abc123).
+{1} - The full path to the assembly that contains the environment resource.</comment>
  </data>
  <data name="XAGRDL1000" xml:space="preserve">
  <value>Executable 'gradlew' not found in project directory '{0}'. Please ensure the path to your Gradle project folder is correct, and that it contains Gradle Wrapper scripts.</value>

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

@@ -243,13 +243,6 @@ void Extract (
  [NuGetPackageId] = nuGetPackageId,
  [NuGetPackageVersion] = nuGetPackageVersion,
  }));
- foreach (var env in Directory.EnumerateFiles (outDirForDll, "__AndroidEnvironment__*", SearchOption.TopDirectoryOnly)) {
- resolvedEnvironments.Add (new TaskItem (env, new Dictionary<string, string> {
- [OriginalFile] = assemblyPath,
- [NuGetPackageId] = nuGetPackageId,
- [NuGetPackageVersion] = nuGetPackageVersion,
- }));
- }
  continue;
  }
 
@@ -267,15 +260,11 @@ void Extract (
 
  // android environment files
  if (name.StartsWith ("__AndroidEnvironment__", StringComparison.OrdinalIgnoreCase)) {
- var outFile = Path.Combine (outDirForDll, name);
- using (var stream = pe.GetEmbeddedResourceStream (resource)) {
- updated |= Files.CopyIfStreamChanged (stream, outFile);
+ if (nuGetPackageId.IsNullOrEmpty ()) {
+ Log.LogCodedWarning ("XA0149", Properties.Resources.XA0149_Assembly, name, assemblyPath);
+ } else {
+ Log.LogCodedWarning ("XA0149", Properties.Resources.XA0149, name, nuGetPackageId, nuGetPackageVersion, assemblyPath);
  }
- resolvedEnvironments.Add (new TaskItem (Path.GetFullPath (outFile), new Dictionary<string, string> {
- [OriginalFile] = assemblyPath,
- [NuGetPackageId] = nuGetPackageId,
- [NuGetPackageVersion] = nuGetPackageVersion,
- }));
  }
  // embedded jars (EmbeddedJar, EmbeddedReferenceJar)
  else if (name.EndsWith (".jar", StringComparison.InvariantCultureIgnoreCase)) {