flutter pub run build_runner build generates missing files and files that contain errors

[talbiislam96]

Hello @graphicbeacon , I followed your Graphql / flutter tutorial using my own GraphQL API , the pub run build_runner build command takes forever and it won't stop running until I hit ctr+c , also it generates files that contain errors due to some missing files ,
What seems to be the problem? I would appreciate some help thank you in advance.

// GENERATED CODE - DO NOT MODIFY BY HAND

import 'package:built_collection/built_collection.dart';
import 'package:built_value/built_value.dart';
import 'package:built_value/serializer.dart';
import 'package:gql_code_builder/src/serializers/default_scalar_serializer.dart'
    as _i1;

part 'schema.schema.gql.g.dart';

abstract class GDate implements Built<GDate, GDateBuilder> {
  GDate._();

  factory GDate([String value]) =>
      _$GDate((b) => value != null ? (b..value = value) : b);

  String get value;
  @BuiltValueSerializer(custom: true)
  static Serializer<GDate> get serializer => _i1.DefaultScalarSerializer<GDate>(
      (Object serialized) => GDate(serialized));
}

class GEntriesTimeSheet extends EnumClass {
  const GEntriesTimeSheet._(String name) : super(name);

  static const GEntriesTimeSheet FULLDAY = _$gEntriesTimeSheetFULLDAY;

  static const GEntriesTimeSheet HALFDAY = _$gEntriesTimeSheetHALFDAY;

  static const GEntriesTimeSheet HALFDAYHALFHOLIDAY =
      _$gEntriesTimeSheetHALFDAYHALFHOLIDAY;

  static const GEntriesTimeSheet NOWORK = _$gEntriesTimeSheetNOWORK;

  static const GEntriesTimeSheet OFF = _$gEntriesTimeSheetOFF;

  static Serializer<GEntriesTimeSheet> get serializer =>
      _$gEntriesTimeSheetSerializer;
  static BuiltSet<GEntriesTimeSheet> get values => _$gEntriesTimeSheetValues;
  static GEntriesTimeSheet valueOf(String name) =>
      _$gEntriesTimeSheetValueOf(name);
}

when I first run it it only generates this file which contain tons of errors, this the stack that I get in the terminal when I run the command:

[WARNING] Deleted previous snapshot due to missing asset graph.
[INFO] Creating build script snapshot......
[INFO] Creating build script snapshot... completed, took 10.9s

[INFO] Initializing inputs
[INFO] Building new asset graph...
[INFO] Building new asset graph completed, took 999ms

[INFO] Checking for unexpected pre-existing outputs....
[INFO] Checking for unexpected pre-existing outputs. completed, took 1ms

[INFO] Running build...
[WARNING] gql_build:serializer_builder on lib/$lib$:
Your current `analyzer` version may not fully support your current SDK version.

Please try upgrading to the latest `analyzer` by running `flutter packages upgrade`.

Analyzer language version: 2.10.0
SDK language version: 2.13.0

If you are getting this message and have the latest analyzer please file
an issue at https://github.com/dart-lang/sdk/issues/new with the title
"No published analyzer available for language version 2.13.0".
Please search the issue tracker first and thumbs up and/or subscribe to
existing issues if present to avoid duplicates.