DatabaseOperations raise ValueError for valid GenericIPAddressField (inet) value with psycopg3

[florianvazelle]

I move recently to psycopg3, and it's seems that the Inet class change to be an alias of ipaddress.ip_address in ​https://github.com/django/django/blob/main/django/db/backends/postgresql/psycopg_any.py#L12.
But some valid inet value raise an ValueError, such as:

>>> import ipaddress
>>> ipaddress.ip_address("192.168.1/24")
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/home/florian/.pyenv/versions/3.11.9/lib/python3.11/ipaddress.py", line 54, in ip_address
    raise ValueError(f'{address!r} does not appear to be an IPv4 or IPv6 address')
ValueError: '192.168.1/24' does not appear to be an IPv4 or IPv6 address

Reference: ​https://www.postgresql.org/docs/current/datatype-net-types.html#DATATYPE-INET

[Simon Charette]

Thank you for your report.

Are you running into this issue by importing the django.db.backends.postgresql.psycopg_any.Inet alias directly or through of of Django's?

​The only internal usage of the Inet alias is through GenericIPAddressField which only supports ​an IPv4 or IPv6 address. In other words, GenericIPAddressField was never meant to support IP ranges such as 192.168.1/24 in the first place from my understanding and it just happened to work by chance on Postgres previously because inet was used as the column type.

[florianvazelle]

I wasn't using Inet directly but through django, so it's missing some prior validations and indications, because the behavior changes between versions of psycopg.

So maybe a InetField would be a good addition?

[Simon Charette]

I wasn't using Inet directly but through django, so it's missing some prior validations and indications, because the behavior changes between versions of psycopg.

I'm not sure what kind of validation its missing

>>> GenericIPAddressField().run_validators('192.168.1/24')
...
ValidationError: ['Enter a valid IPv4 or IPv6 address.']

Obviously if you assign the string value directly to your model instance field and don't trigger ​model validation values won't be validated on save just like assigning a non-email string to an EmailField without calling validation is allowed.

I'm going to close this as invalid and suggest you have a look ​at third-party librairies that provide a field meeting your expectations.