Django 4.2, PyPy and Postgres

[Pete Doherty]

I'm wondering if anyone is using Django 4.2, PyPy 3.10 and Postgres 15?

I tried using psycopg2cffi==2.9.0 and it works up until a point but eventually fails with a series of errors relating to imports.

After adding the compatibility layer to the top of my settings.py script using:

> from psycopg2cffi import compat, errorcodes
> compat.register()


The first error I see is:

> ImportError: cannot import name 'errors' from 'psycopg2cffi' (/home/appuser/.local/lib/pypy3.10/site-packages/psycopg2cffi/__init__.py)

I see the errors module in the psycopg2cffi repo and seem to be able to import it like so:

> import psycopg2cffi
> from psycopg2cffi import compat, errorcodes
psycopg2cffi.errors = errorcodes

I then see an error stating:

> ImportError: cannot import name 'sql' from 'psycopg2cffi' (/home/appuser/.local/lib/pypy3.10/site-packages/psycopg2cffi/__init__.py)

While I see the sql.py module in the repo, it does not seem to be included in the built psycopg2cffi package. Trying to patch it in results in:

> from psycopg2cffi import sql
> psycopg2cffi.sql = sql

> ImportError: cannot import name 'sql' from 'psycopg2cffi' (/home/appuser/.local/lib/pypy3.10/site-packages/psycopg2cffi/__init__.py)

I tried copying sql.py into my locally installed package and that resulted yet another error:

> ImportError: cannot import name 'PY3' from 'psycopg2cffi.compat' (/home/appuser/.local/lib/pypy3.10/site-packages/psycopg2cffi/compat.py)

So, before I go any further down this path, I wanted to see if anyone is using this setup, knows that it will definitely not work or has any suggestions about alternatives.

Thanks!

[Jason]

the last release of psycopg2cffi was January 2021

pypy support for 3.10 came out Dec 2022

Is there a reason you're on psycopg2cffi?  have you tried with regular psycopg2?

[Pete Doherty]

I did try using psycopg2-binary and the app wouldn't start. I'll have to revisit to find what that exact error was. That's a good suggestion, though, as I did not try with the Python (i.e. non-binary) package.

Anyways, the consensus after a quick web search seemed to be to use psycopg2cffi when using PyPy. I'm open to any driver that'll work, though. This is just an experiment.

[Pete Doherty]

Interestingly, I can confirm that using Psycopg 3 does seem to work. I only got it working a few minutes ago, so it has not been thoroughly tested but my test suite passes, which is very encouraging.

Thanks for the nudge, Jason.

[Jason]

sweet, glad this worked out, and hope the initial promise continues to hold true.