Generator output conflicts with retrofit builder

🚨 First, please check:

• existing issues,
• FAQs https://github.com/objectbox/objectbox-dart#faq

1. create a model current_user.dart inside lib folder:

import 'package:objectbox/objectbox.dart';

@Entity()
class CurrentUser {
  @Id(assignable: true)
  int? localId;
  @Unique()
  String? id;
  @Property(type: PropertyType.date)
  DateTime createdAt;
  @Property(type: PropertyType.date)
  DateTime? updatedAt;

  CurrentUser({
    this.localId,
    this.id,
    required this.createdAt,
    this.updatedAt,
  });
}

2. run flutter pub run build_runner build --delete-conflicting-outputs
3. get error:

[INFO] Initializing inputs
[INFO] Building new asset graph...
[SEVERE] Conflicting outputs
Both objectbox_generator:generator and source_gen:combining_builder may output lib/objectbox.g.dart. Potential outputs must be unique across all builders. See https://github.com/dart-lang/build/blob/master/docs/faq.md#why-do-builders-need-unique-outputs
[INFO] Terminating. No further builds will be scheduled

Basic info (please complete the following information):

• ObjectBox version: [1.3.0]
• Flutter/Dart SDK: [2.5.3 / 2.14.4]
• Null-safety enabled: [yes]
• Reproducibility: [always]
• OS: [ macOs BigSur]
• Device/Emulator: [iPhone 13]

Additionally, you can choose to provide more details, e.g. the output of:

• pub deps --no-dev

Dart SDK 2.14.4
Flutter SDK 2.5.3
admin 1.0.0+1
|-- animations 2.0.2
|   '-- flutter...
|-- auto_route 3.1.3
|   |-- collection 1.15.0
|   |-- flutter...
|   |-- path...
|   '-- universal_html 2.0.8
|       |-- async 2.8.1
|       |   |-- collection...
|       |   '-- meta...
|       |-- charcode 1.3.1
|       |-- collection...
|       |-- csslib 0.17.1
|       |   '-- source_span...
|       |-- html 0.15.0
|       |   |-- csslib...
|       |   '-- source_span...
|       |-- meta...
|       |-- source_span 1.8.1
|       |   |-- collection...
|       |   |-- path...
|       |   '-- term_glyph 1.2.0
|       |-- typed_data...
|       '-- universal_io 2.0.4
|           |-- collection...
|           |-- crypto...
|           |-- meta...
|           '-- typed_data...
|-- cupertino_icons 1.0.4
|-- dartz 0.10.0
|-- dio 4.0.3
|   |-- http_parser 4.0.0
|   |   |-- charcode...
|   |   |-- collection...
|   |   |-- source_span...
|   |   |-- string_scanner 1.1.0
|   |   |   |-- charcode...
|   |   |   '-- source_span...
|   |   '-- typed_data...
|   '-- path...
|-- enum_to_string 2.0.1
|-- flare_flutter 3.0.2
|   |-- collection...
|   |-- flutter...
|   '-- meta 1.7.0
|-- flex_color_scheme 4.0.0
|   '-- flutter...
|-- flutter 0.0.0
|   |-- characters 1.1.0
|   |-- collection...
|   |-- meta...
|   |-- sky_engine 0.0.99
|   |-- typed_data 1.3.0
|   |   '-- collection...
|   '-- vector_math 2.1.0
|-- flutter_breadcrumb 1.0.1
|   |-- flutter...
|   '-- pedantic 1.11.1
|-- flutter_hooks 0.18.1
|   '-- flutter...
|-- flutter_secure_storage 5.0.2
|   |-- flutter...
|   |-- flutter_secure_storage_linux 1.1.0
|   |   |-- flutter...
|   |   '-- flutter_secure_storage_platform_interface...
|   |-- flutter_secure_storage_macos 1.1.0
|   |   |-- flutter...
|   |   '-- flutter_secure_storage_platform_interface...
|   |-- flutter_secure_storage_platform_interface 1.0.0
|   |   |-- flutter...
|   |   '-- plugin_platform_interface 2.0.2
|   |       '-- meta...
|   |-- flutter_secure_storage_web 1.0.2
|   |   |-- flutter...
|   |   |-- flutter_secure_storage_platform_interface...
|   |   |-- flutter_web_plugins 0.0.0
|   |   |   |-- characters...
|   |   |   |-- collection...
|   |   |   |-- flutter...
|   |   |   |-- js...
|   |   |   |-- meta...
|   |   |   |-- typed_data...
|   |   |   '-- vector_math...
|   |   '-- js 0.6.3
|   |-- flutter_secure_storage_windows 1.1.2
|   |   |-- flutter...
|   |   '-- flutter_secure_storage_platform_interface...
|   '-- meta...
|-- freezed_annotation 1.0.0
|   |-- collection...
|   |-- json_annotation...
|   '-- meta...
|-- graphql 5.0.0
|   |-- collection...
|   |-- gql 0.13.1-alpha+1635885531641
|   |   |-- collection...
|   |   |-- meta...
|   |   '-- source_span...
|   |-- gql_dedupe_link 2.0.0
|   |   |-- async...
|   |   |-- gql_exec...
|   |   |-- gql_link...
|   |   '-- meta...
|   |-- gql_error_link 0.2.0
|   |   |-- async...
|   |   |-- gql_exec...
|   |   |-- gql_link...
|   |   '-- meta...
|   |-- gql_exec 0.3.0
|   |   |-- collection...
|   |   |-- gql...
|   |   '-- meta...
|   |-- gql_http_link 0.4.0
|   |   |-- gql...
|   |   |-- gql_exec...
|   |   |-- gql_link...
|   |   |-- http...
|   |   |-- http_parser...
|   |   '-- meta...
|   |-- gql_link 0.4.0
|   |   |-- gql...
|   |   |-- gql_exec...
|   |   '-- meta...
|   |-- gql_transform_link 0.2.0
|   |   |-- gql_exec...
|   |   '-- gql_link...
|   |-- hive 2.0.4
|   |   |-- crypto 3.0.1
|   |   |   |-- collection...
|   |   |   '-- typed_data...
|   |   '-- meta...
|   |-- http 0.13.4
|   |   |-- async...
|   |   |-- http_parser...
|   |   |-- meta...
|   |   '-- path...
|   |-- meta...
|   |-- normalize 0.5.5
|   |   |-- collection...
|   |   '-- gql...
|   |-- path...
|   |-- rxdart 0.26.0
|   |-- stream_channel 2.1.0
|   |   '-- async...
|   |-- uuid 3.0.5
|   |   '-- crypto...
|   '-- web_socket_channel 2.1.0
|       |-- async...
|       |-- crypto...
|       '-- stream_channel...
|-- hooks_riverpod 1.0.0
|   |-- collection...
|   |-- flutter...
|   |-- flutter_hooks...
|   |-- flutter_riverpod 1.0.0
|   |   |-- collection...
|   |   |-- flutter...
|   |   |-- meta...
|   |   |-- riverpod...
|   |   '-- state_notifier...
|   |-- riverpod 1.0.0
|   |   |-- collection...
|   |   |-- meta...
|   |   '-- state_notifier...
|   '-- state_notifier 0.7.1
|       '-- meta...
|-- json_annotation 4.3.0
|   '-- meta...
|-- logger 1.1.0
|-- objectbox 1.3.0
|   |-- collection...
|   |-- ffi 1.1.2
|   |-- meta...
|   '-- path...
|-- objectbox_flutter_libs 1.3.0
|   |-- objectbox...
|   '-- path_provider...
|-- path 1.8.0
|-- path_provider 2.0.7
|   |-- flutter...
|   |-- path_provider_android 2.0.7
|   |   |-- flutter...
|   |   '-- path_provider_platform_interface...
|   |-- path_provider_ios 2.0.7
|   |   |-- flutter...
|   |   '-- path_provider_platform_interface...
|   |-- path_provider_linux 2.1.2
|   |   |-- flutter...
|   |   |-- path...
|   |   |-- path_provider_platform_interface...
|   |   '-- xdg_directories 0.2.0
|   |       |-- meta...
|   |       |-- path...
|   |       '-- process 4.2.4
|   |           |-- file 6.1.2
|   |           |   |-- meta...
|   |           |   '-- path...
|   |           |-- path...
|   |           '-- platform...
|   |-- path_provider_macos 2.0.3
|   |   '-- flutter...
|   |-- path_provider_platform_interface 2.0.1
|   |   |-- flutter...
|   |   |-- meta...
|   |   |-- platform 3.0.2
|   |   '-- plugin_platform_interface...
|   '-- path_provider_windows 2.0.4
|       |-- ffi...
|       |-- flutter...
|       |-- meta...
|       |-- path...
|       |-- path_provider_platform_interface...
|       '-- win32 2.3.0
|           '-- ffi...
|-- retrofit 3.0.0
|   |-- dio...
|   '-- meta...
|-- snapping_sheet 3.1.0
|   '-- flutter...
|-- sqlite3_flutter_libs 0.5.1
|   '-- flutter...
'-- ua_client_hints 1.1.0
    '-- flutter...

• flutter doctor -v

Flutter (Channel stable, 2.5.3, on macOS 12.0.1 21A559 darwin-x64, locale en-DE)
    • Flutter version 2.5.3 at /usr/local/Caskroom/flutter/2.2.2/flutter
    • Upstream repository https://github.com/flutter/flutter.git
    • Framework revision 18116933e7 (7 weeks ago), 2021-10-15 10:46:35 -0700
    • Engine revision d3ea636dc5
    • Dart version 2.14.4

[✓] Android toolchain - develop for Android devices (Android SDK version 31.0.0)
    • Android SDK at /Users/jiewang/Library/Android/sdk
    • Platform android-30, build-tools 31.0.0
    • Java binary at: /Applications/Android Studio.app/Contents/jre/Contents/Home/bin/java
    • Java version OpenJDK Runtime Environment (build 11.0.10+0-b96-7281165)
    • All Android licenses accepted.

[✓] Xcode - develop for iOS and macOS
    • Xcode at /Applications/Xcode.app/Contents/Developer
    • Xcode 13.1, Build version 13A1030d
    • CocoaPods version 1.11.2

[✓] Chrome - develop for the web
    • Chrome at /Applications/Google Chrome.app/Contents/MacOS/Google Chrome

[✓] Android Studio (version 2020.3)
    • Android Studio at /Applications/Android Studio.app/Contents
    • Flutter plugin can be installed from:
      🔨 https://plugins.jetbrains.com/plugin/9212-flutter
    • Dart plugin can be installed from:
      🔨 https://plugins.jetbrains.com/plugin/6351-dart
    • Java version OpenJDK Runtime Environment (build 11.0.10+0-b96-7281165)

[✓] VS Code (version 1.62.3)
    • VS Code at /Applications/Visual Studio Code.app/Contents
    • Flutter extension version 3.29.0

[✓] Connected device (1 available)
    • Chrome (web) • chrome • web-javascript • Google Chrome 96.0.4664.55

• No issues found!

Steps to reproduce

1. create a model model.dart;
2. run flutter pub run build_runner build --delete-conflicting-outputs
3. See error

Expected behavior

Should have no errors and generate objectbox.g.dart and objectbox-model.json files.

Code

See above

• Include your pubspec.yaml.

name: admin
description: Admin

publish_to: 'none'

version: 1.0.0+1

environment:
    sdk: '>=2.12.0 <3.0.0'

dependencies:
    animations: ^2.0.2
    auto_route: ^3.1.3
    cupertino_icons: ^1.0.2
    dartz: ^0.10.0
    dio: ^4.0.3
    enum_to_string: ^2.0.1
    flare_flutter: ^3.0.2
    flex_color_scheme: ^4.0.0
    flutter:
        sdk: flutter
    flutter_breadcrumb: ^1.0.1
    flutter_hooks: ^0.18.1
    flutter_secure_storage: ^5.0.2
    freezed_annotation: ^1.0.0
    graphql: ^5.0.0
    hooks_riverpod: ^1.0.0
    json_annotation: ^4.3.0
    logger: ^1.1.0
    objectbox: ^1.3.0
    objectbox_flutter_libs: ^1.3.0
    path: ^1.8.0
    path_provider: ^2.0.7
    retrofit: ^3.0.0
    snapping_sheet: ^3.1.0
    sqlite3_flutter_libs: ^0.5.1
    ua_client_hints: ^1.1.0

dev_dependencies:
    auto_route_generator: ^3.1.0
    build_runner: ^2.1.5
    flutter_lints: ^1.0.0
    flutter_test:
        sdk: flutter
    freezed: ^1.0.0
    json_serializable: ^6.0.1
    objectbox_generator: ^1.3.0
    retrofit_generator: ^3.0.0+1

flutter:
    # The following line ensures that the Material Icons font is
    # included with your application, so that you can use the icons in
    # the material Icons class.
    uses-material-design: true
    # To add assets to your application, add an assets section, like this:
    assets:
        - assets/Teddy.flr
        #- assets/fonts
        #- assets/images
    #   - images/a_dot_ham.jpeg
    # An image asset can refer to one or more resolution-specific "variants", see
    # https://flutter.dev/assets-and-images/#resolution-aware.
    # For details regarding adding assets from package dependencies, see
    # https://flutter.dev/assets-and-images/#from-packages
    # To add custom fonts to your application, add a fonts section here,
    # in this "flutter" section. Each entry in this list should have a
    # "family" key with the font family name, and a "fonts" key with a
    # list giving the asset and other descriptors for the font. For
    # example:
    # fonts:
    #   - family: Schyler
    #     fonts:
    #       - asset: fonts/Schyler-Regular.ttf
    #       - asset: fonts/Schyler-Italic.ttf
    #         style: italic
    #   - family: Trajan Pro
    #     fonts:
    #       - asset: fonts/TrajanPro.ttf
    #       - asset: fonts/TrajanPro_Bold.ttf
    #         weight: 700
    #
    # For details regarding fonts from package dependencies,
    # see https://flutter.dev/custom-fonts/#from-packages

• Include affected entity classes.

current_user.dart:

import 'package:objectbox/objectbox.dart';

@Entity()
class CurrentUser {
  @Id(assignable: true)
  int? localId;
  @Unique()
  String? id;
  @Property(type: PropertyType.date)
  DateTime createdAt;
  @Property(type: PropertyType.date)
  DateTime? updatedAt;

  CurrentUser({
    this.localId,
    this.id,
    required this.createdAt,
    this.updatedAt,
  });
}

login_remote_data_source.dart, generated by retrofit, all other classes are generated by freezed without @Entity() annotation.

part 'login_remote_data_source.g.dart';

final loginRemoteDataSourceProvider = Provider<LoginRemoteDataSource>((ref) {
  return LoginRemoteDataSource(ref.read);
});

@RestApi()
abstract class LoginRemoteDataSource {
  factory LoginRemoteDataSource(Reader reader) =>
      _LoginRemoteDataSource(reader(dioProvider));

  @POST('auth/login')
  Future<CurrentUser> login(@Body() LoginInputData loginInputData);
}

• Please remove any unnecessary or confidential parts.
• At best, link to or attach a project with a failing test.

Logs, stack traces

[WARNING] Bootstrap:
Invalidated precompiled build script due to missing asset graph.
[INFO] Bootstrap:Precompiling build script......
[INFO] Bootstrap:Precompiling build script... completed, took 1.1s

[INFO] BuildDefinition:Initializing inputs
[INFO] BuildDefinition:Building new asset graph...
[SEVERE] BuildDefinition:
Conflicting outputs
Both objectbox_generator:generator and source_gen:combining_builder may output lib/objectbox.g.dart. Potential outputs must be unique across all builders. See https://github.com/dart-lang/build/blob/master/docs/faq.md#why-do-builders-need-unique-outputs
package:build_runner_core/src/asset_graph/graph.dart 507:11          AssetGraph._addGeneratedOutputs
package:build_runner_core/src/asset_graph/graph.dart 452:21          AssetGraph._addInBuildPhaseOutputs
package:build_runner_core/src/asset_graph/graph.dart 411:26          AssetGraph._addOutputsForSources
package:build_runner_core/src/asset_graph/graph.dart 71:9            AssetGraph.build
package:build_runner_core/src/generate/build_definition.dart 253:41  _Loader.prepareWorkspace.<fn>
package:build_runner_core/src/generate/build_definition.dart 251:64  _Loader.prepareWorkspace.<fn>
package:build_runner_core/src/logging/logging.dart 25:30             logTimedAsync
package:build_runner_core/src/generate/build_definition.dart 251:13  _Loader.prepareWorkspace
package:build_runner_core/src/generate/build_impl.dart 114:27        BuildImpl.create
package:build_runner_core/src/generate/build_runner.dart 34:26       BuildRunner.create
package:build_runner/src/generate/build.dart 109:17                  build
package:build_runner/src/entrypoint/build.dart 35:18                 BuildCommand._run
package:args/command_runner.dart 209:13                              CommandRunner.runCommand
package:build_runner/src/entrypoint/run.dart 26:18                   run
.dart_tool/build/entrypoint/build.dart 39:16                         main

[+6787 ms] "flutter run" took 6,969ms.
[   +7 ms] pub finished with exit code 78
[   +1 ms]
           #0      throwToolExit (package:flutter_tools/src/base/common.dart:10:3)
           #1      _DefaultPub.interactively (package:flutter_tools/src/dart/pub.dart:391:7)
           <asynchronous suspension>
           #2      PackagesForwardCommand.runCommand (package:flutter_tools/src/commands/packages.dart:247:5)
           <asynchronous suspension>
           #3      FlutterCommand.run.<anonymous closure> (package:flutter_tools/src/runner/flutter_command.dart:1125:27)
           <asynchronous suspension>
           #4      AppContext.run.<anonymous closure> (package:flutter_tools/src/base/context.dart:150:19)
           <asynchronous suspension>
           #5      CommandRunner.runCommand (package:args/command_runner.dart:209:13)
           <asynchronous suspension>
           #6      FlutterCommandRunner.runCommand.<anonymous closure> (package:flutter_tools/src/runner/flutter_command_runner.dart:288:9)
           <asynchronous suspension>
           #7      AppContext.run.<anonymous closure> (package:flutter_tools/src/base/context.dart:150:19)
           <asynchronous suspension>
           #8      FlutterCommandRunner.runCommand (package:flutter_tools/src/runner/flutter_command_runner.dart:236:5)
           <asynchronous suspension>
           #9      run.<anonymous closure>.<anonymous closure> (package:flutter_tools/runner.dart:62:9)
           <asynchronous suspension>
           #10     AppContext.run.<anonymous closure> (package:flutter_tools/src/base/context.dart:150:19)
           <asynchronous suspension>
           #11     main (package:flutter_tools/executable.dart:92:3)
           <asynchronous suspension>


[  +95 ms] ensureAnalyticsSent: 93ms
[   +1 ms] Running shutdown hooks
[        ] Shutdown hooks complete
[        ] exiting with code 78

Additional context

Add any other context about the problem here.

• Is there anything special about your app?
• May transactions or multi-threading play a role?
• Did you find any workarounds to prevent the issue?

Start with the pubspec.yaml dependencies and the model.dart or current_user.dart reproduction, then run flutter pub run build_runner build --delete-conflicting-outputs. Investigate the builders producing lib/objectbox.g.dart, and consider the expected result: a successful build producing objectbox.g.dart and objectbox-model.json without conflicting-output errors.