Bring back Pydantic 1 compatibility

[potiuk]

The #33956 and #33998 updated limits for Pydantic to Pydantic 2 only and removed Pydantic 1 compatibility. However it turns out that some of important 3rd-party libraries have not yet upgraded and it will make it impossible to install them on Airflow 2.7.1+ if we keep the limit.

For now we bring back Pydantic 1 compatibility, we remove the limit and filter the warnings that made us remove the compatibility code.

---

^ Add meaningful description above
Read the Pull Request Guidelines for more information.
In case of fundamental code changes, an Airflow Improvement Proposal (AIP) is needed.
In case of a new dependency, check compliance with the ASF 3rd Party License Policy.
In case of backwards incompatible changes please leave a note in a newsfragment file, named {pr_number}.significant.rst or {issue_number}.significant.rst, in newsfragments.

[ephraimbuddy]

Should we update here too:

airflow/airflow/serialization/serde.py

Line 322 in 47f79b9

return hasattr(cls, "model_config") and hasattr(cls, "model_fields") and hasattr(cls, "model_fields_set")

?
Like reverting the change in 33956?

[potiuk]

Should we update here too:

airflow/airflow/serialization/serde.py

Line 322 in 47f79b9

return hasattr(cls, "model_config") and hasattr(cls, "model_fields") and hasattr(cls, "model_fields_set")

?
Like reverting the change in 33956?

Good point. We do not reallly use it (yet) - it's been added for AIP-44 but it'sa good point to add check that is v1 and v2 compatible for now

[potiuk]

Updated.

[eladkal]

The cost of trying be ahead :)

[potiuk]

The cost of trying be ahead :)

Living on the edge

[potiuk]

Just a flaky XCom map test that could be likely avoided if we merge #33309

[potiuk]

Merged @ephraimbuddy

[JeroenWilkens]

Hi @potiuk,
Thank you for bringing back support for pydantic v1. This helps us with running Great Expectations on Airflow v2.7.1.

I just noticed however when upgrading, in the constraints file (python 3.8), pydantic is still pinned to version 2.3.0.

[potiuk]

I just noticed however when upgrading, in the constraints file (python 3.8), pydantic is still pinned to version 2.3.0.

Of course. This is the version that is tested and runs with 2.7.1. If you want to downgrade or upgrade any dependency that is different from constraints you should not use constraints. See the docs https://airflow.apache.org/docs/apache-airflow/stable/installation/installing-from-pypi.html#upgrading-and-installing-dependencies-including-providers