[local_auth] Fix enum return on Android (flutter#3780)

The Pigeon conversion in flutter#3748 used a `List<enum>` return value, which Pigeon doesn't support correctly (see flutter/flutter#125230 for catching this earlier next time). Because the method doesn't return any values in integration test environments it wasn't caught (since the issue is in Pigeon message handling, and thus doesn't show up in unit tests of the plugin).

This adds a wrapper class, since enum fields do work.

Fixes flutter/flutter#125214

packages/local_auth/local_auth_android/CHANGELOG.md

@@ -1,3 +1,7 @@
+## 1.0.24
+
+* Fixes `getEnrolledBiometrics` return value handling.
+
 ## 1.0.23
 
 * Switches internals to Pigeon and fixes Java warnings.

packages/local_auth/local_auth_android/android/src/main/java/io/flutter/plugins/localauth/LocalAuthPlugin.java

@@ -24,6 +24,7 @@
 import io.flutter.plugin.common.PluginRegistry;
 import io.flutter.plugins.localauth.AuthenticationHelper.AuthCompletionHandler;
 import io.flutter.plugins.localauth.Messages.AuthClassification;
+import io.flutter.plugins.localauth.Messages.AuthClassificationWrapper;
 import io.flutter.plugins.localauth.Messages.AuthOptions;
 import io.flutter.plugins.localauth.Messages.AuthResult;
 import io.flutter.plugins.localauth.Messages.AuthResultWrapper;
@@ -98,19 +99,23 @@ public LocalAuthPlugin() {}
     return hasBiometricHardware();
   }
 
-  public @NonNull List<AuthClassification> getEnrolledBiometrics() {
-    ArrayList<AuthClassification> biometrics = new ArrayList<>();
+  public @NonNull List<AuthClassificationWrapper> getEnrolledBiometrics() {
+    ArrayList<AuthClassificationWrapper> biometrics = new ArrayList<>();
     if (biometricManager.canAuthenticate(BiometricManager.Authenticators.BIOMETRIC_WEAK)
         == BiometricManager.BIOMETRIC_SUCCESS) {
-      biometrics.add(AuthClassification.WEAK);
+      biometrics.add(wrappedBiometric(AuthClassification.WEAK));
     }
     if (biometricManager.canAuthenticate(BiometricManager.Authenticators.BIOMETRIC_STRONG)
         == BiometricManager.BIOMETRIC_SUCCESS) {
-      biometrics.add(AuthClassification.STRONG);
+      biometrics.add(wrappedBiometric(AuthClassification.STRONG));
     }
     return biometrics;
   }
 
+  private @NonNull AuthClassificationWrapper wrappedBiometric(AuthClassification value) {
+    return new AuthClassificationWrapper.Builder().setValue(value).build();
+  }
+
   public @NonNull Boolean stopAuthentication() {
     try {
       if (authHelper != null && authInProgress.get()) {

packages/local_auth/local_auth_android/android/src/main/java/io/flutter/plugins/localauth/Messages.java

@@ -538,6 +538,55 @@ ArrayList<Object> toList() {
     }
   }
 
+  /** Generated class from Pigeon that represents data sent in messages. */
+  public static final class AuthClassificationWrapper {
+    private @NonNull AuthClassification value;
+
+    public @NonNull AuthClassification getValue() {
+      return value;
+    }
+
+    public void setValue(@NonNull AuthClassification setterArg) {
+      if (setterArg == null) {
+        throw new IllegalStateException("Nonnull field \"value\" is null.");
+      }
+      this.value = setterArg;
+    }
+
+    /** Constructor is non-public to enforce null safety; use Builder. */
+    AuthClassificationWrapper() {}
+
+    public static final class Builder {
+
+      private @Nullable AuthClassification value;
+
+      public @NonNull Builder setValue(@NonNull AuthClassification setterArg) {
+        this.value = setterArg;
+        return this;
+      }
+
+      public @NonNull AuthClassificationWrapper build() {
+        AuthClassificationWrapper pigeonReturn = new AuthClassificationWrapper();
+        pigeonReturn.setValue(value);
+        return pigeonReturn;
+      }
+    }
+
+    @NonNull
+    ArrayList<Object> toList() {
+      ArrayList<Object> toListResult = new ArrayList<Object>(1);
+      toListResult.add(value == null ? null : value.index);
+      return toListResult;
+    }
+
+    static @NonNull AuthClassificationWrapper fromList(@NonNull ArrayList<Object> list) {
+      AuthClassificationWrapper pigeonResult = new AuthClassificationWrapper();
+      Object value = list.get(0);
+      pigeonResult.setValue(value == null ? null : AuthClassification.values()[(int) value]);
+      return pigeonResult;
+    }
+  }
+
   public interface Result<T> {
     @SuppressWarnings("UnknownNullness")
     void success(T result);
@@ -554,10 +603,12 @@ private LocalAuthApiCodec() {}
     protected Object readValueOfType(byte type, @NonNull ByteBuffer buffer) {
       switch (type) {
         case (byte) 128:
-          return AuthOptions.fromList((ArrayList<Object>) readValue(buffer));
+          return AuthClassificationWrapper.fromList((ArrayList<Object>) readValue(buffer));
         case (byte) 129:
-          return AuthResultWrapper.fromList((ArrayList<Object>) readValue(buffer));
+          return AuthOptions.fromList((ArrayList<Object>) readValue(buffer));
         case (byte) 130:
+          return AuthResultWrapper.fromList((ArrayList<Object>) readValue(buffer));
+        case (byte) 131:
           return AuthStrings.fromList((ArrayList<Object>) readValue(buffer));
         default:
           return super.readValueOfType(type, buffer);
@@ -566,14 +617,17 @@ protected Object readValueOfType(byte type, @NonNull ByteBuffer buffer) {
 
     @Override
     protected void writeValue(@NonNull ByteArrayOutputStream stream, Object value) {
-      if (value instanceof AuthOptions) {
+      if (value instanceof AuthClassificationWrapper) {
         stream.write(128);
+        writeValue(stream, ((AuthClassificationWrapper) value).toList());
+      } else if (value instanceof AuthOptions) {
+        stream.write(129);
         writeValue(stream, ((AuthOptions) value).toList());
       } else if (value instanceof AuthResultWrapper) {
-        stream.write(129);
+        stream.write(130);
         writeValue(stream, ((AuthResultWrapper) value).toList());
       } else if (value instanceof AuthStrings) {
-        stream.write(130);
+        stream.write(131);
         writeValue(stream, ((AuthStrings) value).toList());
       } else {
         super.writeValue(stream, value);
@@ -603,7 +657,7 @@ public interface LocalAuthApi {
      * Returns the biometric types that are enrolled, and can thus be used without additional setup.
      */
     @NonNull
-    List<AuthClassification> getEnrolledBiometrics();
+    List<AuthClassificationWrapper> getEnrolledBiometrics();
     /**
      * Attempts to authenticate the user with the provided [options], and using [strings] for any
      * UI.
@@ -695,7 +749,7 @@ static void setup(@NonNull BinaryMessenger binaryMessenger, @Nullable LocalAuthA
               (message, reply) -> {
                 ArrayList<Object> wrapped = new ArrayList<Object>();
                 try {
-                  List<AuthClassification> output = api.getEnrolledBiometrics();
+                  List<AuthClassificationWrapper> output = api.getEnrolledBiometrics();
                   wrapped.add(0, output);
                 } catch (Throwable exception) {
                   ArrayList<Object> wrappedError = wrapError(exception);

packages/local_auth/local_auth_android/android/src/test/java/io/flutter/plugins/localauth/LocalAuthTest.java

@@ -30,6 +30,7 @@
 import io.flutter.plugin.common.BinaryMessenger;
 import io.flutter.plugins.localauth.AuthenticationHelper.AuthCompletionHandler;
 import io.flutter.plugins.localauth.Messages.AuthClassification;
+import io.flutter.plugins.localauth.Messages.AuthClassificationWrapper;
 import io.flutter.plugins.localauth.Messages.AuthOptions;
 import io.flutter.plugins.localauth.Messages.AuthResult;
 import io.flutter.plugins.localauth.Messages.AuthResultWrapper;
@@ -291,7 +292,7 @@ public void getEnrolledBiometrics_shouldReturnEmptyList_withoutHardwarePresent()
         .thenReturn(BiometricManager.BIOMETRIC_ERROR_NO_HARDWARE);
     plugin.setBiometricManager(mockBiometricManager);
 
-    final List<AuthClassification> enrolled = plugin.getEnrolledBiometrics();
+    final List<AuthClassificationWrapper> enrolled = plugin.getEnrolledBiometrics();
     assertTrue(enrolled.isEmpty());
   }
 
@@ -304,7 +305,7 @@ public void getEnrolledBiometrics_shouldReturnEmptyList_withNoMethodsEnrolled()
         .thenReturn(BiometricManager.BIOMETRIC_ERROR_NONE_ENROLLED);
     plugin.setBiometricManager(mockBiometricManager);
 
-    final List<AuthClassification> enrolled = plugin.getEnrolledBiometrics();
+    final List<AuthClassificationWrapper> enrolled = plugin.getEnrolledBiometrics();
     assertTrue(enrolled.isEmpty());
   }
 
@@ -319,9 +320,9 @@ public void getEnrolledBiometrics_shouldOnlyAddEnrolledBiometrics() {
         .thenReturn(BiometricManager.BIOMETRIC_ERROR_NONE_ENROLLED);
     plugin.setBiometricManager(mockBiometricManager);
 
-    final List<AuthClassification> enrolled = plugin.getEnrolledBiometrics();
+    final List<AuthClassificationWrapper> enrolled = plugin.getEnrolledBiometrics();
     assertEquals(1, enrolled.size());
-    assertEquals(AuthClassification.WEAK, enrolled.get(0));
+    assertEquals(AuthClassification.WEAK, enrolled.get(0).getValue());
   }
 
   @Test
@@ -335,10 +336,10 @@ public void getEnrolledBiometrics_shouldAddStrongBiometrics() {
         .thenReturn(BiometricManager.BIOMETRIC_SUCCESS);
     plugin.setBiometricManager(mockBiometricManager);
 
-    final List<AuthClassification> enrolled = plugin.getEnrolledBiometrics();
+    final List<AuthClassificationWrapper> enrolled = plugin.getEnrolledBiometrics();
     assertEquals(2, enrolled.size());
-    assertEquals(AuthClassification.WEAK, enrolled.get(0));
-    assertEquals(AuthClassification.STRONG, enrolled.get(1));
+    assertEquals(AuthClassification.WEAK, enrolled.get(0).getValue());
+    assertEquals(AuthClassification.STRONG, enrolled.get(1).getValue());
   }
 
   @Test

packages/local_auth/local_auth_android/lib/local_auth_android.dart

@@ -96,9 +96,12 @@ class LocalAuthAndroid extends LocalAuthPlatform {
 
   @override
   Future<List<BiometricType>> getEnrolledBiometrics() async {
-    final List<AuthClassification?> result = await _api.getEnrolledBiometrics();
-    return result.cast<AuthClassification>().map((AuthClassification entry) {
-      switch (entry) {
+    final List<AuthClassificationWrapper?> result =
+        await _api.getEnrolledBiometrics();
+    return result
+        .cast<AuthClassificationWrapper>()
+        .map((AuthClassificationWrapper entry) {
+      switch (entry.value) {
         case AuthClassification.weak:
           return BiometricType.weak;
         case AuthClassification.strong:

packages/local_auth/local_auth_android/lib/src/messages.g.dart

@@ -174,19 +174,43 @@ class AuthResultWrapper {
   }
 }
 
+class AuthClassificationWrapper {
+  AuthClassificationWrapper({
+    required this.value,
+  });
+
+  AuthClassification value;
+
+  Object encode() {
+    return <Object?>[
+      value.index,
+    ];
+  }
+
+  static AuthClassificationWrapper decode(Object result) {
+    result as List<Object?>;
+    return AuthClassificationWrapper(
+      value: AuthClassification.values[result[0]! as int],
+    );
+  }
+}
+
 class _LocalAuthApiCodec extends StandardMessageCodec {
   const _LocalAuthApiCodec();
   @override
   void writeValue(WriteBuffer buffer, Object? value) {
-    if (value is AuthOptions) {
+    if (value is AuthClassificationWrapper) {
       buffer.putUint8(128);
       writeValue(buffer, value.encode());
-    } else if (value is AuthResultWrapper) {
+    } else if (value is AuthOptions) {
       buffer.putUint8(129);
       writeValue(buffer, value.encode());
-    } else if (value is AuthStrings) {
+    } else if (value is AuthResultWrapper) {
       buffer.putUint8(130);
       writeValue(buffer, value.encode());
+    } else if (value is AuthStrings) {
+      buffer.putUint8(131);
+      writeValue(buffer, value.encode());
     } else {
       super.writeValue(buffer, value);
     }
@@ -196,10 +220,12 @@ class _LocalAuthApiCodec extends StandardMessageCodec {
   Object? readValueOfType(int type, ReadBuffer buffer) {
     switch (type) {
       case 128:
-        return AuthOptions.decode(readValue(buffer)!);
+        return AuthClassificationWrapper.decode(readValue(buffer)!);
       case 129:
-        return AuthResultWrapper.decode(readValue(buffer)!);
+        return AuthOptions.decode(readValue(buffer)!);
       case 130:
+        return AuthResultWrapper.decode(readValue(buffer)!);
+      case 131:
         return AuthStrings.decode(readValue(buffer)!);
       default:
         return super.readValueOfType(type, buffer);
@@ -304,7 +330,7 @@ class LocalAuthApi {
 
   /// Returns the biometric types that are enrolled, and can thus be used
   /// without additional setup.
-  Future<List<AuthClassification?>> getEnrolledBiometrics() async {
+  Future<List<AuthClassificationWrapper?>> getEnrolledBiometrics() async {
     final BasicMessageChannel<Object?> channel = BasicMessageChannel<Object?>(
         'dev.flutter.pigeon.LocalAuthApi.getEnrolledBiometrics', codec,
         binaryMessenger: _binaryMessenger);
@@ -326,7 +352,8 @@ class LocalAuthApi {
         message: 'Host platform returned null value for non-null return value.',
       );
     } else {
-      return (replyList[0] as List<Object?>?)!.cast<AuthClassification?>();
+      return (replyList[0] as List<Object?>?)!
+          .cast<AuthClassificationWrapper?>();
     }
   }
 

packages/local_auth/local_auth_android/pigeons/messages.dart

@@ -94,6 +94,13 @@ class AuthResultWrapper {
 /// Pigeon equivalent of the subset of BiometricType used by Android.
 enum AuthClassification { weak, strong }
 
+// TODO(stuartmorgan): Remove this when
+// https://github.com/flutter/flutter/issues/87307 is implemented.
+class AuthClassificationWrapper {
+  AuthClassificationWrapper({required this.value});
+  final AuthClassification value;
+}
+
 @HostApi()
 abstract class LocalAuthApi {
   /// Returns true if this device supports authentication.
@@ -111,7 +118,7 @@ abstract class LocalAuthApi {
 
   /// Returns the biometric types that are enrolled, and can thus be used
   /// without additional setup.
-  List<AuthClassification> getEnrolledBiometrics();
+  List<AuthClassificationWrapper> getEnrolledBiometrics();
 
   /// Attempts to authenticate the user with the provided [options], and using
   /// [strings] for any UI.

packages/local_auth/local_auth_android/pubspec.yaml

@@ -2,7 +2,7 @@ name: local_auth_android
 description: Android implementation of the local_auth plugin.
 repository: https://github.com/flutter/packages/tree/main/packages/local_auth/local_auth_android
 issue_tracker: https://github.com/flutter/flutter/issues?q=is%3Aissue+is%3Aopen+label%3A%22p%3A+local_auth%22
-version: 1.0.23
+version: 1.0.24
 
 environment:
   sdk: ">=2.17.0 <4.0.0"

packages/local_auth/local_auth_android/test/local_auth_test.dart

@@ -65,11 +65,11 @@ void main() {
 
   group('getEnrolledBiometrics', () {
     test('translates values', () async {
-      when(api.getEnrolledBiometrics()).thenAnswer((_) async =>
-          <AuthClassification>[
-            AuthClassification.weak,
-            AuthClassification.strong
-          ]);
+      when(api.getEnrolledBiometrics())
+          .thenAnswer((_) async => <AuthClassificationWrapper>[
+                AuthClassificationWrapper(value: AuthClassification.weak),
+                AuthClassificationWrapper(value: AuthClassification.strong),
+              ]);
 
       final List<BiometricType> result = await plugin.getEnrolledBiometrics();
 
@@ -81,7 +81,7 @@ void main() {
 
     test('handles emtpy', () async {
       when(api.getEnrolledBiometrics())
-          .thenAnswer((_) async => <AuthClassification>[]);
+          .thenAnswer((_) async => <AuthClassificationWrapper>[]);
 
       final List<BiometricType> result = await plugin.getEnrolledBiometrics();
 

packages/local_auth/local_auth_android/test/local_auth_test.mocks.dart

@@ -63,15 +63,15 @@ class MockLocalAuthApi extends _i1.Mock implements _i2.LocalAuthApi {
         returnValue: _i3.Future<bool>.value(false),
       ) as _i3.Future<bool>);
   @override
-  _i3.Future<List<_i2.AuthClassification?>> getEnrolledBiometrics() =>
+  _i3.Future<List<_i2.AuthClassificationWrapper?>> getEnrolledBiometrics() =>
       (super.noSuchMethod(
         Invocation.method(
           #getEnrolledBiometrics,
           [],
         ),
-        returnValue: _i3.Future<List<_i2.AuthClassification?>>.value(
-            <_i2.AuthClassification?>[]),
-      ) as _i3.Future<List<_i2.AuthClassification?>>);
+        returnValue: _i3.Future<List<_i2.AuthClassificationWrapper?>>.value(
+            <_i2.AuthClassificationWrapper?>[]),
+      ) as _i3.Future<List<_i2.AuthClassificationWrapper?>>);
   @override
   _i3.Future<_i2.AuthResultWrapper> authenticate(
     _i2.AuthOptions? arg_options,