[pigeon] Fixes error from constructor parameter sharing name with attached field for a ProxyApi (#10541)

Attached parameters aren't passed in constructor message call so they can share name with constructor parameter. 

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Author: bparrishMines

packages/pigeon/CHANGELOG.md

@@ -1,5 +1,6 @@
-## NEXT
+## 26.1.3
 
+* [dart] Fixes error from constructor parameter sharing name with attached field for a ProxyApi.
 * Updates minimum supported SDK version to Flutter 3.35/Dart 3.9.
 
 ## 26.1.2

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 = '26.1.2';
+const String pigeonVersion = '26.1.3';
 
 /// Read all the content from [stdin] to a String.
 String readStdin() {

packages/pigeon/lib/src/pigeon_lib_internal.dart

@@ -1079,7 +1079,10 @@ List<Error> _validateProxyApi(
         result.add(unsupportedDataClassError(parameter));
       }
 
-      if (api.fields.any((ApiField field) => field.name == parameter.name) ||
+      if (api.fields.any(
+            (ApiField field) =>
+                field.name == parameter.name && !field.isAttached,
+          ) ||
           api.flutterMethods.any(
             (Method method) => method.name == parameter.name,
           )) {

packages/pigeon/pubspec.yaml

@@ -2,7 +2,7 @@ name: pigeon
 description: Code generator tool to make communication between Flutter and the host platform type-safe and easier.
 repository: https://github.com/flutter/packages/tree/main/packages/pigeon
 issue_tracker: https://github.com/flutter/flutter/issues?q=is%3Aissue+is%3Aopen+label%3A%22p%3A+pigeon%22
-version: 26.1.2 # This must match the version in lib/src/generator_tools.dart
+version: 26.1.3 # This must match the version in lib/src/generator_tools.dart
 
 environment:
   sdk: ^3.9.0

packages/pigeon/test/pigeon_lib_test.dart

@@ -1757,6 +1757,39 @@ abstract class MyClass {
         ),
       );
     });
+
+    test('constructor parameters can share name of attached fields', () {
+      const code = '''
+@ProxyApi()
+abstract class MyClass {
+  MyClass(int aField);
+
+  @attached
+  late MyClass aField;
+}
+''';
+      final ParseResults parseResult = parseSource(code);
+      expect(parseResult.errors, isEmpty);
+    });
+
+    test('constructor parameters can not share name of unattached fields', () {
+      const code = '''
+@ProxyApi()
+abstract class MyClass {
+  MyClass(int aField);
+
+  late MyClass? aField;
+}
+''';
+      final ParseResults parseResult = parseSource(code);
+      expect(parseResult.errors, isNotEmpty);
+      expect(
+        parseResult.errors[0].message,
+        contains(
+          'Parameter names must not share a name with a field or callback method in constructor "" in API: "MyClass"',
+        ),
+      );
+    });
   });
 
   group('event channel validation', () {