[pigeon] Support lists-and-maps of lists-and-maps

packages/pigeon/CHANGELOG.md

@@ -1,3 +1,8 @@
+## 26.3.4
+
+* [dart] Supports serializing Lists of Lists and Maps, and serializing Maps of
+  Lists and Maps.
+
 ## 26.3.3
 
 * Updates `analyzer` dependency to support versions 10 through 12.

packages/pigeon/lib/src/dart/dart_generator.dart

@@ -1597,9 +1597,43 @@ String _castValue(String value, TypeDeclaration type) {
   }
 
   final nullAwareOperator = type.isNullable ? '?' : '';
-  final castCall =
-      '$nullAwareOperator.cast<${_flattenTypeArguments(typeArguments)}>()';
-  return '($valueWithTypeCast)$castCall';
+  return '($valueWithTypeCast)$nullAwareOperator.${_castCall(type)}';
+}
+
+/// Returns the code that casts a `List<Object?>` or a `Map<Object?, Object?>`
+/// to a specific List or Map [type], considering nested List or Map type
+/// arguments.
+///
+/// Given a simple [type], like `List<int>`, the returned code is a simple call
+/// to [List.cast]: `cast<int>()`.
+///
+/// Given a deep List type, like `List<List<int>>`, the returned code uses
+/// [List.map] and [List.cast]:
+/// `map((e) => (e! as List<Object?>).cast<int>()).toList()`.
+///
+/// Given a deep Map type, like `Map<int, List<int>>`, the returned code uses
+/// [Map.map] and [Map.cast]:
+/// `map((k, v) => MapEntry(k! as int, (v! as List<Object?>).cast<int>()))`.
+String _castCall(TypeDeclaration type) {
+  if (type.baseName == 'List') {
+    final TypeDeclaration typeArgument = type.typeArguments.first;
+    if (typeArgument.baseName == 'List' || typeArgument.baseName == 'Map') {
+      // We must cast each element in `valueWithTypeCast`.
+      return 'map((e) => ${_castValue('e', typeArgument)}).toList()';
+    }
+  } else if (type.baseName == 'Map') {
+    if (type.typeArguments.any(
+      (e) => e.baseName == 'List' || e.baseName == 'Map',
+    )) {
+      final TypeDeclaration keyTypeArgument = type.typeArguments[0];
+      final TypeDeclaration valueTypeArgument = type.typeArguments[1];
+      return 'map((k, v) => MapEntry('
+          '${_castValue('k', keyTypeArgument)}, '
+          '${_castValue('v', valueTypeArgument)}))';
+    }
+  }
+
+  return 'cast<${_flattenTypeArguments(type.typeArguments)}>()';
 }
 
 /// Returns an argument name that can be used in a context where it is possible to collide.

packages/pigeon/lib/src/generator_tools.dart

@@ -15,7 +15,7 @@ import 'generator.dart';
 /// The current version of pigeon.
 ///
 /// This must match the version in pubspec.yaml.
-const String pigeonVersion = '26.3.3';
+const String pigeonVersion = '26.3.4';
 
 /// Default plugin package name.
 const String defaultPluginPackageName = 'dev.flutter.pigeon';

packages/pigeon/pigeons/core_tests.dart

@@ -44,7 +44,9 @@ class AllTypes {
     required this.enumList,
     required this.objectList,
     required this.listList,
+    required this.boolListList,
     required this.mapList,
+    required this.boolMapList,
 
     // Maps
     required this.map,
@@ -53,6 +55,7 @@ class AllTypes {
     required this.enumMap,
     required this.objectMap,
     required this.listMap,
+    required this.boolListMap,
     required this.mapMap,
   });
 
@@ -79,7 +82,9 @@ class AllTypes {
   List<AnEnum> enumList;
   List<Object> objectList;
   List<List<Object?>> listList;
+  List<List<bool>> boolListList;
   List<Map<Object?, Object?>> mapList;
+  List<Map<int, bool>> boolMapList;
 
   // Maps
   // ignore: strict_raw_type, always_specify_types
@@ -89,6 +94,7 @@ class AllTypes {
   Map<AnEnum, AnEnum> enumMap;
   Map<Object, Object> objectMap;
   Map<int, List<Object?>> listMap;
+  Map<int, List<bool>> boolListMap;
   Map<int, Map<Object?, Object?>> mapMap;
 }
 
@@ -121,6 +127,7 @@ class AllNullableTypes {
     this.enumList,
     this.objectList,
     this.listList,
+    this.boolListList,
     this.mapList,
     this.recursiveClassList,
 
@@ -131,6 +138,7 @@ class AllNullableTypes {
     this.enumMap,
     this.objectMap,
     this.listMap,
+    this.boolListMap,
     this.mapMap,
     this.recursiveClassMap,
   );
@@ -159,6 +167,7 @@ class AllNullableTypes {
   List<AnEnum?>? enumList;
   List<Object?>? objectList;
   List<List<Object?>?>? listList;
+  List<List<bool?>?>? boolListList;
   List<Map<Object?, Object?>?>? mapList;
   List<AllNullableTypes?>? recursiveClassList;
 
@@ -170,6 +179,7 @@ class AllNullableTypes {
   Map<AnEnum?, AnEnum?>? enumMap;
   Map<Object?, Object?>? objectMap;
   Map<int?, List<Object?>?>? listMap;
+  Map<int?, List<bool?>?>? boolListMap;
   Map<int?, Map<Object?, Object?>?>? mapMap;
   Map<int?, AllNullableTypes?>? recursiveClassMap;
 }
@@ -354,6 +364,11 @@ abstract class HostIntegrationCoreApi {
   @SwiftFunction('echoNonNull(classList:)')
   List<AllNullableTypes> echoNonNullClassList(List<AllNullableTypes> classList);
 
+  /// Returns the passed list, to test serialization and deserialization.
+  @ObjCSelector('echoNonNullBoolListList:')
+  @SwiftFunction('echoNonNull(boolListList:)')
+  List<List<bool>> echoNonNullBoolListList(List<List<bool>> list);
+
   /// Returns the passed map, to test serialization and deserialization.
   @ObjCSelector('echoMap:')
   @SwiftFunction('echo(_:)')