flutter pub run build_runner 构建失败

Question

flutter version:

flutter_macos_v1.9.1+hotfix.2-stable

create new project in terminal:

flutter create myapp

open vscode, edit pubspec.yaml :

dependencies:
  json_annotation: ^3.0.0

dev_dependencies:
  build_runner: ^1.7.0
  json_serializable: ^3.2.2

get packages in terminal:

flutter pub get

new /lib/user.dart and filling below:

import 'package:json_annotation/json_annotation.dart';

part 'user.g.dart';

@JsonSerializable()
class User extends Object {
  @JsonKey(name: 'seed')
  String seed;

  @JsonKey(name: 'results')
  int results;

  @JsonKey(name: 'page')
  int page;

  @JsonKey(name: 'version')
  String version;

  User(
    this.seed,
    this.results,
    this.page,
    this.version,
  );

  factory User.fromJson(Map<String, dynamic> srcJson) =>
      _$UserFromJson(srcJson);

  Map<String, dynamic> toJson() => _$UserToJson(this);
}

run flutter pub run build_runner build in terminal:

[INFO] Generating build script...
[INFO] Generating build script completed, took 321ms

[INFO] Creating build script snapshot......
[INFO] Creating build script snapshot... completed, took 10.4s

[INFO] Initializing inputs
[INFO] Building new asset graph...
[INFO] Building new asset graph completed, took 698ms

[INFO] Checking for unexpected pre-existing outputs....
[INFO] Checking for unexpected pre-existing outputs. completed, took 2ms

[INFO] Running build...
[SEVERE] json_serializable:json_serializable on lib/user.dart:

Invalid argument(s): Path must be absolute : dart:core
[SEVERE] json_serializable:json_serializable on lib/main.dart:

Invalid argument(s): Path must be absolute : dart:core
[SEVERE] json_serializable:json_serializable on test/widget_test.dart:

Invalid argument(s): Path must be absolute : dart:core
[INFO] Running build completed, took 1.5s

[INFO] Caching finalized dependency graph...
[INFO] Caching finalized dependency graph completed, took 36ms

[SEVERE] Failed after 1.6s

why never succeeded?!

Answer 1

Try this.

flutter pub get && flutter pub run build_runner build --delete-conflicting-outputs

Answer 2

add dependency in pubsec.yaml, analyzer: '0.39.14'

flutter clean
flutter pub cache repair
flutter pub run build_runner clean

Then run,

flutter pub run build_runner build

Answer 3

I tried with many solutions, But error not gone. flutter packages pub run build_runner watch command ran with endless log.

I deleted pubspec.lock and ran flutter pub get and installed dependency again and ran above command. After this error gone.

Answer 4

I had the same issue, so I just saved the changes first in the class (in your case User class).
And then I just retried using:

flutter pub run build_runner build

Answer 5

Please create default empty constructor for models class before flutter packages pub run build_runner build command

Answer 6

I got this to work with the latest build_runner and json_serializable versions after a long process of trying all of the above suggestions: build_runner: ^1.10.2 json_serializable: ^3.4.0 Not sure what ultimately worked, but looks like one of the issues in my case was a slightly outdated dart SDK, so that's one more thing to keep an eye on

Answer 7

Looks like Analyzer is breaking it, downgrading to analyzer: 0.38.2 solved it for me.

Source: https://github.com/dart-lang/sdk/issues/38499#issuecomment-533812652

Answer 8

I had the same issue.

Successfully generating all *.g.dart files with:

build_runner 0.9.2

json_serializable 0.5.8+1

json_annotation 0.2.9+1

Answer 9

It might not be the case in this situation, but I had a similar problem caused by my auto formatter removing this line:

part 'my_class.g.dart';

Once I added that line and ran the command again it worked fine.

Answer 10

I had the same error. I simply installed the build runner package in pubspec.yaml file like -

dev_dependencies:

build_runner: ^1.3.1

mobx_codegen: ^0.3.9

Answer 11

you may need hive_generator in your dependencies

Answer 12

Update 2020/8/24: seems to break build_runner or json_serializable in version:

Analyzer: 0.39.16 

Going back to dart analyzer version:

Analyzer: 0.39.14 

fixed it for me. So, something is broken in 0.39.16.

Answer 13

My class name was:

class Game

but my filename was game_model.dart So you'll need to use:

part 'game_model.g.dart';

You may also need to add hive_generator dependency.

Answer 14

Looks like flutter clean is resolving the issue. Try running it before ie openApi Generator.

Answer 15

make sure the class name is same with the generated file name. For ex:

part ' User .g.dart';

class User {

}