flutter build runner not working - The getter 'uri' was called on null

Question

I was using flutter with build runner perfectly , but today it just getting this null error . Even thought I reverted my code changes but still the same error .

the error :

>[SEVERE] json_serializable:json_serializable on test/widget_test.dart:

>NoSuchMethodError: The getter 'uri' was called on null.
>Receiver: null
>Tried calling: uri
>[INFO] 3.3s elapsed, 1/17 actions completed.
>[INFO] 4.4s elapsed, 1/17 actions completed.
>[INFO] 5.4s elapsed, 1/17 actions completed.
>[INFO] 6.4s elapsed, 1/17 actions completed.
>[INFO] 7.5s elapsed, 1/17 actions completed.
>[INFO] 8.5s elapsed, 1/17 actions completed.
>[INFO] 9.6s elapsed, 1/17 actions completed.
>[INFO] 10.7s elapsed, 1/17 actions completed.
>[INFO] 11.8s elapsed, 1/17 actions completed.
>[INFO] 12.9s elapsed, 1/17 actions completed.
>[INFO] 14.0s elapsed, 1/17 actions completed.
>[INFO] 15.0s elapsed, 1/17 actions completed.
>[INFO] 16.1s elapsed, 1/17 actions completed.
>[INFO] 17.1s elapsed, 1/17 actions completed.
>[WARNING] No actions completed for 15.1s, waiting on:
>  json_serializable:json_serializable on lib/common_widgets/alert_screens.dart
>  json_serializable:json_serializable on lib/common_widgets/app_logo.dart
>  json_serializable:json_serializable on lib/common_widgets/app_tab_bar.dart
>  json_serializable:json_serializable on lib/common_widgets/buttons_widgets.dart
>  json_serializable:json_serializable on lib/common_widgets/cards.dart
>  .. and 11 more
>  [INFO] 18.2s elapsed, 1/17 actions completed.
>  [INFO] 19.3s elapsed, 1/17 actions completed.

and it keeps going on like that .

I am using :

    sdk: ">=2.7.0 <3.0.0"
    flutter: ^1.22.0
    build_runner: ^1.10.0
    json_serializable: ^3.5.0
    analyzer: ^0.41.1

the model I am trying to generate :

    import 'package:flutter/foundation.dart';
    import 'package:json_annotation/json_annotation.dart';
    
    part 'clinic.g.dart';
    
    @JsonSerializable()
    class Clinic {
      final int establishmentYear;
      final String workingHours;
      final String phoneNumber;
      final String location;
    
      Clinic({
        @required this.establishmentYear,
        @required this.workingHours,
        @required this.phoneNumber,
        @required this.location,
      });
    
      factory Clinic.fromJson(Map<String, dynamic> json) => _$ClinicFromJson(json);
      Map<String, dynamic> toJson() => _$ClinicToJson(this);
    }

Solution

Updating to latest flutter version solved the issue