Why method annotation are immutable?

[KeidsID]

I mean Dio didn't force const for the request headers.

Dio(BaseOptions(
  baseUrl: 'https://api.themoviedb.org/$kTmdbApiVersion',
  headers: {"Authorization": "Bearer ${Env.tmdbAccToken}"},
));

Steps to Reproduce

1. SDKs & packages Versions

   environment:
    sdk: ^3.0.0 # v3.0.2
    flutter: ^3.10.0 # v3.10.2
   
   dependencies:
    flutter:
      sdk: flutter
   
    chopper: ^7.0.9
    envied: ^0.5.2
   
   dev_dependencies:
    flutter_test:
      sdk: flutter
   
    flutter_lints: ^3.0.1
   
    build_runner: ^2.4.6
    chopper_generator: ^7.0.6
    envied_generator: ^0.5.2

2. create dummy .env file on project root.

   API_KEY=dummy4p1K3y

3. create an obfuscate Env class.

   @Envied(obfuscate: true)
   abstract final class Env {
    @EnviedField(varName: 'API_KEY')
    static final String apiKey = _Env.apiKey; //it's final because there's a step to decrypt it.
   }

4. fetch dependencies then generate env.

   flutter pub get
   dart run build_runner build -d

5. try using the chopper API.

   mixin ClientHeaders on ChopperService {
    Map<String, String> get headers => {'x-api-key': Env.apiKey};
   }
   
   @ChopperApi(baseUrl: '/users')
   abstract class UsersService extends ChopperService with ClientHeaders {
    @Get(headers: headers) // WHY IMMUTABLE?
    Future<Response<String>> getUserByEmail() {}
   }

Expected results: No Error At All

Actual results: immutable for the [GET] annotation

Code sample

```dart import 'package:chopper/chopper.dart'; import 'package:envied/envied.dart'; import 'package:flutter/material.dart'; part 'main.chopper.dart'; part 'main.g.dart'; void main() { runApp(const MainApp()); } class MainApp extends StatelessWidget { const MainApp({super.key}); @override Widget build(BuildContext context) { return const MaterialApp( home: Scaffold( body: Center( child: Text('Hello World!'), ), ), ); } } @Envied(obfuscate: true) abstract final class Env { @EnviedField(varName: 'API_KEY') static final String apiKey = _Env.apiKey; // it's final because there's a step to decrypt it. } mixin ClientHeaders on ChopperService { Map get headers => {'x-api-key': Env.apiKey}; } @ChopperApi(baseUrl: '/users') abstract class UsersService extends ChopperService with ClientHeaders { @Get(headers: headers) // WHY IMMUTABLE? Future> getUserByEmail() {} } ```

Logs

``` ``` ``` Analyzing chopper_headers_issue... error • lib\chopper_example.dart:13:17 • Arguments of a constant creation must be constant expressions. Try making the argument a valid constant, or use 'new' to call the constructor. • const_with_non_constant_argument error • lib\chopper_example.dart:14:28 • The body might complete normally, causing 'null' to be returned, but the return type, 'Future>', is a potentially non-nullable type. Try adding either a return or a throw statement at the end. • body_might_complete_normally error • lib\main.dart:39:17 • Arguments of a constant creation must be constant expressions. Try making the argument a valid constant, or use 'new' to call the constructor. • const_with_non_constant_argument error • lib\main.dart:40:28 • The body might complete normally, causing 'null' to be returned, but the return type, 'Future>', is a potentially non-nullable type. Try adding either a return or a throw statement at the end. • body_might_complete_normally info • lib\chopper_example.chopper.dart:10:13 • The declaration '_$UsersService' isn't referenced. Try removing the declaration of '_$UsersService'. • unused_element info • lib\main.chopper.dart:10:13 • The declaration '_$UsersService' isn't referenced. Try removing the declaration of '_$UsersService'. • unused_element 6 issues found. ``` ``` Flutter 3.10.2 • channel stable • https://github.com/flutter/flutter.git Framework • revision 9cd3d0d9ff (6 months ago) • 2023-05-23 20:57:28 -0700 Engine • revision 90fa3ae28f Tools • Dart 3.0.2 • DevTools 2.23.1 ```

[KeidsID]

I really like the chopper API after read the docs, but can't use it because of this.

[techouse]

If you want it dynamic simply use it like this

Future<Response<String>> getUserByEmail(
  @Header() String? name, // <-- like this
) {}

And please, don't use this approach to handle auth. Use the dedicated authenticator interceptor for that.