[dart][dart-dio] Add built_value date support w/o timemachine

[kuhnroyal]

Fixes #9095

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[kuhnroyal]

CC @swipesight (2018/09) @jaumard (2018/09) @josh-burton (2019/12) @amondnet (2019/12) @sbu-WBT (2020/12) @kuhnroyal (2020/12) @agilob (2020/12)

[jannikrh]

While testing the generator and thereby this PR, I noticed two problems. The first one is directly related to the extension. The second one might be a separate issue for which I can open a new issue.

1. In the file serializers.dart the import for the new Date class is missing.

import 'package:trainer_api/src/model/date.dart';

Which leads to the following errors.

error - Undefined name 'Date' - lib\src\serializers.g.dart:34:59 - undefined_identifier
error - The name 'Date' isn't a type so it can't be used as a type argument - lib\src\serializers.g.dart:35:33 - non_type_as_type_argument

2. When using a pure type: object the import package:built_value/json_object.dart; for the JsonObject is missing.

[kuhnroyal]

Do you have an example spec or repro?
The date import should not be needed since the date serializer is added, not sure.

Please create a new issue for 2. and CC me.

[jannikrh]

The problem occurs in this basic example. With flutter analyze, the missing import is noticeable. In this case, import 'model/date.dart'; needs to added to serializers.dart.

error - Undefined name 'Date' - lib\src\serializers.g.dart:12:59 - undefined_identifier
error - The name 'Date' isn't a type so it can't be used as a type argument - lib\src\serializers.g.dart:13:33 - non_type_as_type_argument

openapi: 3.0.1
info:
  version: 1.0.0
  title: Trainer
paths:
  /test:
    get:
      responses:
        '200':
          description: Groups
          content:
            application/json:
                schema:
                  type: array
                  items:
                    type: object
                    required:
                      - uuid
                      - name
                      - dates
                    properties:
                      uuid:
                        type: string
                        format: uuid
                      name:
                        type: string
                        example: Group A
                      trainingDates:
                        type: array
                        description: Training dates
                        items:
                          type: string
                          format: date
                          

[kuhnroyal]

I see, an array of dates.

[kuhnroyal]

1. should be fixed

[kuhnroyal]

Shippable failure is unrelated.

[jannikrh]

1. should be fixed

Now works as intended.

[kuhnroyal]

Looking for reviews

[wing328]

All tests passed after restart.