Unable to serialize UUIDField when running dumpdata with JSON format

[James Beith]

A model using a UUIDField as its primary key. Running dumpdata management command with JSON output format (the default option) resulted in the following error

CommandError: Unable to serialize database: UUID('435697b4-954a-4b9a-a83a-2b53016b0d43') is not JSON serializable

However running again with --format=xml did not result in an error and dumpdata was successful.

[Tim Graham]

I created a custom user with UUID pk:

import uuid

from django.contrib.auth.models import AbstractUser
from django.db import models


class UUIDUser(AbstractUser):
    id = models.UUIDField(primary_key=True, default=uuid.uuid4)

And then tried:

python manage.py dumpdata uuiduser.UUIDUser
[{"fields": {"username": "tim", "first_name": "", "last_name": "", "is_active": true,
"is_superuser": true, "is_staff": true, "last_login": "2015-02-11T19:01:02.747Z",
"groups": [], "user_permissions": [], "password": "...", "email": "a@g.com",
"date_joined": "2015-02-11T18:55:33.572Z"}, "model": "uuiduser.uuiduser",
"pk": "dd100fcd-a894-4435-ad30-bdcd4671ac44"}]

Tested on SQLite and PostgreSQL. Could you provide more details? I'm also attached a test for Django's test suite that I tried writing to reproduce the issue.

[Tim Graham <timograham@…>]

In d7509c52466aeffb13ccd8a86475e74fdb0e6292:

Added a test for UUIDField serialization; refs #24320.

[Tim Graham <timograham@…>]

In 8d1816db87e9e700d9bd5336ac25686fdf30c789:

[1.8.x] Added a test for UUIDField serialization; refs #24320.

Backport of d7509c52466aeffb13ccd8a86475e74fdb0e6292 from master

[Tim Graham]

Please reopen with more details if this is still an issue.

[James Beith]

I have created an example project which reproduces the issue.

[James Beith]

Example project

[Tim Graham]

Thanks. Problem seems to be having a FK to an object with a UUID pk. Attaching a failing test for Django's test suite.

[Andriy Sokolovskiy]

I will try to fix this

[Andriy Sokolovskiy]

​https://github.com/django/django/pull/4123

[Tim Graham]

There are at least two open tickets related to this that may be duplicates or warrant concurrent investigation: #9422 and #17587. By the way, it's easier if you open your PR against master and let the committer backport from there.

[Andriy Sokolovskiy]

Opened new PR to master:
​https://github.com/django/django/pull/4125

[Tim Graham <timograham@…>]

In 5c995dcfc251b55284e1ef16545acd2acad6be04:

Fixed #24320 - Used field.value_to_string() in serialization of foreign key.

This fixes serialization of a ForeignKey to a UUIDField as the
test indicates.

[Tim Graham <timograham@…>]

In 136edac8974ff0b570ce0a3e66e7aadf542225f0:

[1.8.x] Fixed #24320 - Used field.value_to_string() in serialization of foreign key.

This fixes serialization of a ForeignKey to a UUIDField as the
test indicates.

Backport of 5c995dcfc251b55284e1ef16545acd2acad6be04 from master