[pigeon] adds support for non nullable types in collections (#7547)

[pigeon] adds support for non nullable types in collections

fixes flutter/flutter#97848

Author: tarrinneal

packages/pigeon/CHANGELOG.md

@@ -1,3 +1,7 @@
+## 22.4.0
+
+* Adds support for non-nullable types in collections.
+
 ## 22.3.0
 
 * Adds support for enums and classes in collections.

packages/pigeon/lib/dart_generator.dart

@@ -2159,8 +2159,8 @@ String _getMethodParameterSignature(Iterable<Parameter> parameters) {
 String _flattenTypeArguments(List<TypeDeclaration> args) {
   return args
       .map<String>((TypeDeclaration arg) => arg.typeArguments.isEmpty
-          ? '${arg.baseName}?'
-          : '${arg.baseName}<${_flattenTypeArguments(arg.typeArguments)}>?')
+          ? '${arg.baseName}${arg.isNullable ? '?' : ''}'
+          : '${arg.baseName}<${_flattenTypeArguments(arg.typeArguments)}>${arg.isNullable ? '?' : ''}')
       .join(', ');
 }
 

packages/pigeon/lib/generator_tools.dart

@@ -14,7 +14,7 @@ import 'ast.dart';
 /// The current version of pigeon.
 ///
 /// This must match the version in pubspec.yaml.
-const String pigeonVersion = '22.3.0';
+const String pigeonVersion = '22.4.0';
 
 /// Read all the content from [stdin] to a String.
 String readStdin() {

packages/pigeon/lib/objc_generator.dart

@@ -297,7 +297,7 @@ class ObjcHeaderGenerator extends StructuredGenerator<ObjcOptions> {
       final _ObjcType returnType = _objcTypeForDartType(
         generatorOptions.prefix, func.returnType,
         // Nullability is required since the return must be nil if NSError is set.
-        forceNullability: true,
+        forceBox: true,
       );
       final String callbackType =
           _callbackForType(func.returnType, returnType, generatorOptions);
@@ -336,7 +336,7 @@ class ObjcHeaderGenerator extends StructuredGenerator<ObjcOptions> {
         func.returnType,
         // Nullability is required since the return must be nil if NSError is
         // set.
-        forceNullability: true,
+        forceBox: true,
       );
 
       String? lastArgName;
@@ -1072,7 +1072,7 @@ static FlutterError *createConnectionError(NSString *channelName) {
       final _ObjcType returnType = _objcTypeForDartType(
         generatorOptions.prefix, func.returnType,
         // Nullability is required since the return must be nil if NSError is set.
-        forceNullability: true,
+        forceBox: true,
       );
       final Iterable<String> selectorComponents =
           _getSelectorComponents(func, lastSelectorComponent);
@@ -1187,7 +1187,7 @@ void _writeMethod(
     languageOptions.prefix,
     func.returnType,
     // Nullability is required since the return must be nil if NSError is set.
-    forceNullability: true,
+    forceBox: true,
   );
   final String callbackType =
       _callbackForType(func.returnType, returnType, languageOptions);
@@ -1444,23 +1444,23 @@ String _flattenTypeArguments(String? classPrefix, List<TypeDeclaration> args) {
       return _enumName(e.baseName,
           prefix: classPrefix, box: true, suffix: ' *');
     }
-    return _objcTypeForDartType(classPrefix, e).toString();
+    return _objcTypeForDartType(classPrefix, e, forceBox: true).toString();
   }).join(', ');
   return result;
 }
 
 _ObjcType? _objcTypeForPrimitiveDartType(TypeDeclaration type,
-    {bool forceNullability = false}) {
-  return forceNullability || type.isNullable
+    {bool forceBox = false}) {
+  return forceBox || type.isNullable
       ? _objcTypeForNullableDartTypeMap[type.baseName]
       : _objcTypeForNonNullableDartTypeMap[type.baseName];
 }
 
 String? _objcTypeStringForPrimitiveDartType(
     String? classPrefix, TypeDeclaration type,
-    {required bool beforeString, bool forceNullability = false}) {
+    {required bool beforeString, bool forceBox = false}) {
   final _ObjcType? objcType;
-  if (forceNullability || type.isNullable) {
+  if (forceBox || type.isNullable) {
     objcType = _objcTypeForNullableDartTypeMap.containsKey(type.baseName)
         ? _objcTypeForDartType(classPrefix, type)
         : null;
@@ -1475,14 +1475,14 @@ String? _objcTypeStringForPrimitiveDartType(
 /// Returns the Objective-C type for a Dart [field], prepending the
 /// [classPrefix] for generated classes.
 _ObjcType _objcTypeForDartType(String? classPrefix, TypeDeclaration field,
-    {bool forceNullability = false}) {
+    {bool forceBox = false}) {
   final _ObjcType? primitiveType =
-      _objcTypeForPrimitiveDartType(field, forceNullability: forceNullability);
+      _objcTypeForPrimitiveDartType(field, forceBox: forceBox);
   return primitiveType == null
       ? _ObjcType(
           baseName: _className(classPrefix, field.baseName),
           // Non-nullable enums are non-pointer types.
-          isPointer: !field.isEnum || (field.isNullable || forceNullability))
+          isPointer: !field.isEnum || (field.isNullable || forceBox))
       : field.typeArguments.isEmpty
           ? primitiveType
           : _ObjcType(

packages/pigeon/lib/pigeon_lib.dart

@@ -971,15 +971,6 @@ List<Error> _validateAst(Root root, String source) {
           lineNumber: _calculateLineNumberNullable(source, field.offset),
         ));
       }
-      for (final TypeDeclaration typeArgument in field.type.typeArguments) {
-        if (!typeArgument.isNullable) {
-          result.add(Error(
-            message:
-                'Generic type parameters must be nullable in field "${field.name}" in class "${classDefinition.name}".',
-            lineNumber: _calculateLineNumberNullable(source, field.offset),
-          ));
-        }
-      }
       if (!(validTypes.contains(field.type.baseName) ||
           customClasses.contains(field.type.baseName) ||
           customEnums.contains(field.type.baseName))) {

packages/pigeon/lib/swift_generator.dart

@@ -1031,8 +1031,7 @@ String _flattenTypeArguments(List<TypeDeclaration> args) {
 }
 
 String _swiftTypeForBuiltinGenericDartType(TypeDeclaration type) {
-  if (type.typeArguments.isEmpty ||
-      (type.typeArguments.first.baseName == 'Object')) {
+  if (type.typeArguments.isEmpty) {
     if (type.baseName == 'List') {
       return '[Any?]';
     } else if (type.baseName == 'Map') {
@@ -1044,14 +1043,17 @@ String _swiftTypeForBuiltinGenericDartType(TypeDeclaration type) {
     if (type.baseName == 'List') {
       return '[${_nullSafeSwiftTypeForDartType(type.typeArguments.first)}]';
     } else if (type.baseName == 'Map') {
-      return '[${_nullSafeSwiftTypeForDartType(type.typeArguments.first)}: ${_nullSafeSwiftTypeForDartType(type.typeArguments.last)}]';
+      return '[${_nullSafeSwiftTypeForDartType(type.typeArguments.first, mapKey: true)}: ${_nullSafeSwiftTypeForDartType(type.typeArguments.last)}]';
     } else {
       return '${type.baseName}<${_flattenTypeArguments(type.typeArguments)}>';
     }
   }
 }
 
-String? _swiftTypeForBuiltinDartType(TypeDeclaration type) {
+String? _swiftTypeForBuiltinDartType(
+  TypeDeclaration type, {
+  bool mapKey = false,
+}) {
   const Map<String, String> swiftTypeForDartTypeMap = <String, String>{
     'void': 'Void',
     'bool': 'Bool',
@@ -1065,7 +1067,9 @@ String? _swiftTypeForBuiltinDartType(TypeDeclaration type) {
     'Float64List': 'FlutterStandardTypedData',
     'Object': 'Any',
   };
-  if (swiftTypeForDartTypeMap.containsKey(type.baseName)) {
+  if (mapKey && type.baseName == 'Object') {
+    return 'AnyHashable';
+  } else if (swiftTypeForDartTypeMap.containsKey(type.baseName)) {
     return swiftTypeForDartTypeMap[type.baseName];
   } else if (type.baseName == 'List' || type.baseName == 'Map') {
     return _swiftTypeForBuiltinGenericDartType(type);
@@ -1074,13 +1078,16 @@ String? _swiftTypeForBuiltinDartType(TypeDeclaration type) {
   }
 }
 
-String _swiftTypeForDartType(TypeDeclaration type) {
-  return _swiftTypeForBuiltinDartType(type) ?? type.baseName;
+String _swiftTypeForDartType(TypeDeclaration type, {bool mapKey = false}) {
+  return _swiftTypeForBuiltinDartType(type, mapKey: mapKey) ?? type.baseName;
 }
 
-String _nullSafeSwiftTypeForDartType(TypeDeclaration type) {
+String _nullSafeSwiftTypeForDartType(
+  TypeDeclaration type, {
+  bool mapKey = false,
+}) {
   final String nullSafe = type.isNullable ? '?' : '';
-  return '${_swiftTypeForDartType(type)}$nullSafe';
+  return '${_swiftTypeForDartType(type, mapKey: mapKey)}$nullSafe';
 }
 
 String _getMethodSignature({