Marshmallow hooks on schema inheritance

[codectl]

How can we chain Marshmallow hooks when you use schema inheritance?

Suppose the following "dumb" example:

from marshmallow import Schema, fields, post_load


class PersonSchema(Schema):
    name = fields.Str()

    @post_load
    def post_load(self, data, **_):
        data["name"] = data["name"].capitalize()
        return data


class EmployeeSchema(PersonSchema):
    title = fields.Str()

    @post_load
    def post_load(self, data, **_):
        data["title"] = data["title"].upper()
        return data

EmployeeSchema().load({"name": "john", "title": "ceo"})
# {"name": "john", "title": "CEO"}

In this example, only the subclassed hook was triggered. How do you make the parent hook trigger as well on deserialization, in this case?

[lafrech]

This is not specific to marshmallow, but a Python issue. The child class overrides post_load method. Give it another name.

class PersonSchema(Schema):
    name = fields.Str()

    @post_load
    def capitalize(self, data, **_):
        data["name"] = data["name"].capitalize()
        return data


class EmployeeSchema(PersonSchema):
    title = fields.Str()

    @post_load
    def upper(self, data, **_):
        data["title"] = data["title"].upper()
        return data

Note the order is not guaranteed (#600).