✨ call .toString() on non-String headers

chopper/test/base_test.dart

@@ -9,6 +9,7 @@ import 'package:http/testing.dart';
 import 'package:test/test.dart';
 import 'package:transparent_image/transparent_image.dart';
 
+import 'fixtures/example_enum.dart';
 import 'test_service.dart';
 import 'test_service_base_url.dart';
 import 'test_service_variable.dart';
@@ -1616,4 +1617,36 @@ void main() {
 
     httpClient.close();
   });
+
+  test('headers are always stringified', () async {
+    final httpClient = MockClient((request) async {
+      expect(
+        request.url.toString(),
+        equals('$baseUrl/test/headers'),
+      );
+      expect(request.method, equals('GET'));
+      expect(request.headers['x-string'], equals('lorem'));
+      expect(request.headers['x-boolean'], equals('true'));
+      expect(request.headers['x-int'], equals('42'));
+      expect(request.headers['x-double'], equals('42.42'));
+      expect(request.headers['x-enum'], equals('baz'));
+
+      return http.Response('get response', 200);
+    });
+
+    final chopper = buildClient(httpClient, JsonConverter());
+    final service = chopper.getService<HttpTestService>();
+
+    final response = await service.getHeaders(
+      stringHeader: 'lorem',
+      boolHeader: true,
+      intHeader: 42,
+      doubleHeader: 42.42,
+      enumHeader: ExampleEnum.baz,
+    );
+
+    expect(response.statusCode, equals(200));
+
+    httpClient.close();
+  });
 }

chopper/test/fixtures/example_enum.dart

@@ -0,0 +1,8 @@
+enum ExampleEnum {
+  foo,
+  bar,
+  baz;
+
+  @override
+  String toString() => name;
+}

chopper/test/test_service.dart

@@ -4,6 +4,8 @@ import 'dart:convert';
 import 'package:chopper/chopper.dart';
 import 'package:http/http.dart' show MultipartFile;
 
+import 'fixtures/example_enum.dart';
+
 part 'test_service.chopper.dart';
 
 @ChopperApi(baseUrl: '/test')
@@ -193,6 +195,15 @@ abstract class HttpTestService extends ChopperService {
   Future<Response<String>> getDateTime(
     @Query('value') DateTime value,
   );
+
+  @Get(path: 'headers')
+  Future<Response<String>> getHeaders({
+    @Header('x-string') required String stringHeader,
+    @Header('x-boolean') bool? boolHeader,
+    @Header('x-int') int? intHeader,
+    @Header('x-double') double? doubleHeader,
+    @Header('x-enum') ExampleEnum? enumHeader,
+  });
 }
 
 Request customConvertRequest(Request req) {

chopper_generator/lib/src/generator.dart

@@ -676,18 +676,24 @@ final class ChopperGenerator
   ) {
     final StringBuffer codeBuffer = StringBuffer('')..writeln('{');
 
-    /// Search for @Header anotation in method parameters
+    /// Search for @Header annotation in method parameters
     final Map<ParameterElement, ConstantReader> annotations =
         _getAnnotations(methodElement, chopper.Header);
 
-    annotations.forEach((parameter, ConstantReader annotation) {
+    annotations.forEach((
+      ParameterElement parameter,
+      ConstantReader annotation,
+    ) {
       final String paramName = parameter.displayName;
       final String name = annotation.peek('name')?.stringValue ?? paramName;
-
+      final String headerValue = switch (parameter.type.isDartCoreString) {
+        true => "'$name': $paramName,",
+        false => "'$name': $paramName.toString(),",
+      };
       if (parameter.type.isNullable) {
-        codeBuffer.writeln('if ($paramName != null) \'$name\': $paramName,');
+        codeBuffer.writeln('if ($paramName != null) $headerValue');
       } else {
-        codeBuffer.writeln('\'$name\': $paramName,');
+        codeBuffer.writeln(headerValue);
       }
     });
 
@@ -700,7 +706,7 @@ final class ChopperGenerator
     methodAnnotations.forEach((headerName, headerValue) {
       if (headerName != null && headerValue != null) {
         codeBuffer.writeln(
-          '\'${headerName.toStringValue()}\': ${literal(headerValue.toStringValue())},',
+          "'${headerName.toStringValue()}': ${literal(headerValue.toStringValue())},",
         );
       }
     });

chopper_generator/test/test_service.dart

@@ -188,6 +188,15 @@ abstract class HttpTestService extends ChopperService {
   Future<Response<String>> getUsingMapQueryParamWithBrackets(
     @Query('value') Map<String, dynamic> value,
   );
+
+  @Get(path: 'headers')
+  Future<Response<String>> getHeaders({
+    @Header('x-string') required String stringHeader,
+    @Header('x-boolean') bool? boolHeader,
+    @Header('x-int') int? intHeader,
+    @Header('x-double') double? doubleHeader,
+    @Header('x-enum') ExampleEnum? enumHeader,
+  });
 }
 
 Request customConvertRequest(Request req) {
@@ -216,3 +225,12 @@ Request convertForm(Request req) {
 
   return req;
 }
+
+enum ExampleEnum {
+  foo,
+  bar,
+  baz;
+
+  @override
+  String toString() => name;
+}