ordered = True not respected

class BaseSchema(Schema):
     id = fields.Int(dump_only=True)

class LineItemSchema(BaseSchema):
    name = fields.Str(attribute='label')

class CampaignSchema(BaseSchema):
    name = fields.Str(attribute='campaign_name')
    line_items = fields.Nested(LineItemSchema, many=True)

    class Meta:
        fields = ("id", "name", "line_items")
        ordered = True

When I run: result = campaign_schema.dump(campaign) json.dumps(result.data)

I get this output:

{
    "id": 1, 
    "line_items": [
        {
            "id": 1, 
            "name": "mpu"
        }, 
        {
            "id": 3, 
            "name": "banner"
        }
    ], 
    "name": "test"
}

I had a look in my debugger - think it’s something to do with that some of the field names are the same? Perhaps something to do with how ret is constructed here: https://github.com/marshmallow-code/marshmallow/blob/dev/marshmallow/schema.py#L729

Let me know if I’m missing something in my config somewhere!

[azzamsa]

This also happens in flask-smorest 0.22.0. All you need to do is disable JSON_SORT_KEYS in your config, as @halfar-aspire mentioned.

app = Flask(__name__)
app.config['JSON_SORT_KEYS'] = False

[billmccord]

This has something to do with json.dumps. I traced it into that method and it is not respecting the OrderedDict at least in Python 3.5.1. If you are using Flask-Restful, this could be why: http://flask-restful-cn.readthedocs.org/en/latest/extending.html “Note If the application is running in debug mode (app.debug = True) and either sort_keys or indent are not declared in the RESTFUL_JSON configuration setting, Flask-RESTful will provide defaults of True and 4 respectively.”