[pigeon] adds support for collections of enums and classes (#7476)

adds support for collections of enums and classes
fixes flutter/flutter#133728

Author: tarrinneal

packages/pigeon/CHANGELOG.md

@@ -1,3 +1,7 @@
+## 22.3.0
+
+* Adds support for enums and classes in collections.
+
 ## 22.2.0
 
 * [kotlin] Adds implementation for `@ProxyApi`.

packages/pigeon/example/app/ios/Runner/Messages.g.swift

@@ -113,7 +113,7 @@ private class MessagesPigeonCodecReader: FlutterStandardReader {
   override func readValue(ofType type: UInt8) -> Any? {
     switch type {
     case 129:
-      let enumResultAsInt: Int? = nilOrValue(self.readValue() as? Int)
+      let enumResultAsInt: Int? = nilOrValue(self.readValue() as! Int?)
       if let enumResultAsInt = enumResultAsInt {
         return Code(rawValue: enumResultAsInt)
       }
@@ -191,8 +191,8 @@ class ExampleHostApiSetup {
     if let api = api {
       addChannel.setMessageHandler { message, reply in
         let args = message as! [Any?]
-        let aArg = args[0] is Int64 ? args[0] as! Int64 : Int64(args[0] as! Int32)
-        let bArg = args[1] is Int64 ? args[1] as! Int64 : Int64(args[1] as! Int32)
+        let aArg = args[0] as! Int64
+        let bArg = args[1] as! Int64
         do {
           let result = try api.add(aArg, to: bArg)
           reply(wrapResult(result))

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 = '22.2.0';
+const String pigeonVersion = '22.3.0';
 
 /// Read all the content from [stdin] to a String.
 String readStdin() {

packages/pigeon/lib/pigeon_lib.dart

@@ -979,13 +979,6 @@ List<Error> _validateAst(Root root, String source) {
             lineNumber: _calculateLineNumberNullable(source, field.offset),
           ));
         }
-        if (customEnums.contains(typeArgument.baseName)) {
-          result.add(Error(
-            message:
-                'Enum types aren\'t supported in type arguments in "${field.name}" in class "${classDefinition.name}".',
-            lineNumber: _calculateLineNumberNullable(source, field.offset),
-          ));
-        }
       }
       if (!(validTypes.contains(field.type.baseName) ||
           customClasses.contains(field.type.baseName) ||

packages/pigeon/lib/swift_generator.dart

@@ -145,7 +145,7 @@ class SwiftGenerator extends StructuredGenerator<SwiftOptions> {
       indent.nest(1, () {
         if (customType.type == CustomTypes.customEnum) {
           indent.writeln(
-              'let enumResultAsInt: Int? = nilOrValue(self.readValue() as? Int)');
+              'let enumResultAsInt: Int? = nilOrValue(self.readValue() as! Int?)');
           indent.writeScoped('if let enumResultAsInt = enumResultAsInt {', '}',
               () {
             indent.writeln(
@@ -419,7 +419,7 @@ if (wrapped == nil) {
   }
 
   void _writeClassField(Indent indent, NamedType field, {bool addNil = true}) {
-    indent.add('${field.name}: ${_nullsafeSwiftTypeForDartType(field.type)}');
+    indent.add('${field.name}: ${_nullSafeSwiftTypeForDartType(field.type)}');
     final String defaultNil = field.type.isNullable && addNil ? ' = nil' : '';
     indent.add(defaultNil);
   }
@@ -487,7 +487,17 @@ if (wrapped == nil) {
               getFieldsInSerializationOrder(classDefinition).last == field
                   ? ''
                   : ',';
-          indent.writeln('${field.name}: ${field.name}$comma');
+          // Force-casting nullable enums in maps doesn't work the same as other types.
+          // It needs soft-casting followed by force unwrapping.
+          final String forceUnwrapMapWithNullableEnums =
+              (field.type.baseName == 'Map' &&
+                      !field.type.isNullable &&
+                      field.type.typeArguments
+                          .any((TypeDeclaration type) => type.isEnum))
+                  ? '!'
+                  : '';
+          indent.writeln(
+              '${field.name}: ${field.name}$forceUnwrapMapWithNullableEnums$comma');
         }
       });
     });
@@ -650,14 +660,11 @@ if (wrapped == nil) {
     assert(!type.isVoid);
     if (type.baseName == 'Object') {
       return value + (type.isNullable ? '' : '!');
-    } else if (type.baseName == 'int') {
-      if (type.isNullable) {
-        // Nullable ints need to check for NSNull, and Int32 before casting can be done safely.
-        // This nested ternary is a necessary evil to avoid less efficient conversions.
-        return 'isNullish($value) ? nil : ($value is Int64? ? $value as! Int64? : Int64($value as! Int32))';
-      } else {
-        return '$value is Int64 ? $value as! Int64 : Int64($value as! Int32)';
-      }
+      // Force-casting nullable enums in maps doesn't work the same as other types.
+      // It needs soft-casting followed by force unwrapping.
+    } else if (type.baseName == 'Map' &&
+        type.typeArguments.any((TypeDeclaration type) => type.isEnum)) {
+      return '$value as? ${_swiftTypeForDartType(type)}';
     } else if (type.isNullable) {
       return 'nilOrValue($value)';
     } else {
@@ -846,7 +853,13 @@ private func nilOrValue<T>(_ value: Any?) -> T? {
               fieldType: fieldType,
               type: returnType,
             );
-            indent.writeln('completion(.success(result))');
+            // There is a swift bug with unwrapping maps of nullable Enums;
+            final String enumMapForceUnwrap = returnType.baseName == 'Map' &&
+                    returnType.typeArguments
+                        .any((TypeDeclaration type) => type.isEnum)
+                ? '!'
+                : '';
+            indent.writeln('completion(.success(result$enumMapForceUnwrap))');
           }
         });
       });
@@ -887,6 +900,12 @@ private func nilOrValue<T>(_ value: Any?) -> T? {
             final String argName = _getSafeArgumentName(index, arg.namedType);
             final String argIndex = 'args[$index]';
             final String fieldType = _swiftTypeForDartType(arg.type);
+            // There is a swift bug with unwrapping maps of nullable Enums;
+            final String enumMapForceUnwrap = arg.type.baseName == 'Map' &&
+                    arg.type.typeArguments
+                        .any((TypeDeclaration type) => type.isEnum)
+                ? '!'
+                : '';
 
             _writeGenericCasting(
                 indent: indent,
@@ -896,9 +915,10 @@ private func nilOrValue<T>(_ value: Any?) -> T? {
                 type: arg.type);
 
             if (arg.label == '_') {
-              methodArgument.add(argName);
+              methodArgument.add('$argName$enumMapForceUnwrap');
             } else {
-              methodArgument.add('${arg.label ?? arg.name}: $argName');
+              methodArgument
+                  .add('${arg.label ?? arg.name}: $argName$enumMapForceUnwrap');
             }
           });
         }
@@ -1022,9 +1042,9 @@ String _swiftTypeForBuiltinGenericDartType(TypeDeclaration type) {
     }
   } else {
     if (type.baseName == 'List') {
-      return '[${_nullsafeSwiftTypeForDartType(type.typeArguments.first)}]';
+      return '[${_nullSafeSwiftTypeForDartType(type.typeArguments.first)}]';
     } else if (type.baseName == 'Map') {
-      return '[${_nullsafeSwiftTypeForDartType(type.typeArguments.first)}: ${_nullsafeSwiftTypeForDartType(type.typeArguments.last)}]';
+      return '[${_nullSafeSwiftTypeForDartType(type.typeArguments.first)}: ${_nullSafeSwiftTypeForDartType(type.typeArguments.last)}]';
     } else {
       return '${type.baseName}<${_flattenTypeArguments(type.typeArguments)}>';
     }
@@ -1058,7 +1078,7 @@ String _swiftTypeForDartType(TypeDeclaration type) {
   return _swiftTypeForBuiltinDartType(type) ?? type.baseName;
 }
 
-String _nullsafeSwiftTypeForDartType(TypeDeclaration type) {
+String _nullSafeSwiftTypeForDartType(TypeDeclaration type) {
   final String nullSafe = type.isNullable ? '?' : '';
   return '${_swiftTypeForDartType(type)}$nullSafe';
 }
@@ -1080,10 +1100,10 @@ String _getMethodSignature({
     swiftFunction: swiftFunction,
   );
   final String returnTypeString =
-      returnType.isVoid ? 'Void' : _nullsafeSwiftTypeForDartType(returnType);
+      returnType.isVoid ? 'Void' : _nullSafeSwiftTypeForDartType(returnType);
 
   final Iterable<String> types =
-      parameters.map((NamedType e) => _nullsafeSwiftTypeForDartType(e.type));
+      parameters.map((NamedType e) => _nullSafeSwiftTypeForDartType(e.type));
   final Iterable<String> labels = indexMap(components.arguments,
       (int index, _SwiftFunctionArgument argument) {
     return argument.label ?? _getArgumentName(index, argument.namedType);