pydantic 2.0 dependency

[jneo8]

Bug Description

The pydantic just released 2.0.
So the charm build and and the PY_DEPS in library is broken.
Also maybe some fixs are requried for pydantic related code.

To Reproduce

tox -e render-machine
charmcraft pack

Environment

ubuntu 20.04

Relevant log output

...

Temporary workaround

Pin pydantic version < 2.0 in PY_DEPS

# PYDEPS = ["cosl", "pydantic"]
PYDEPS = ["cosl", "pydantic < 2.0"]

Additional context

No response

[PietroPasotti]

just had the same issue in tempo, had to pin it to "<2.0" and it worked for now

[dragomirp]

Hi, at the moment clean builds of charms using lib/charms/grafana_agent/v0/cos_agent.py would try to pull pydantic 2.0 and fail to pack at least on focal. This happens because charmcraft is updating dependencies based on what is specified in the PYDEPS of charm libs. There's a bug canonical/charmcraft#1135 open for it, but short term charm libs should most probably pin the major version in PYDEPS.