Exceptions do not properly pickle and unpickle

[amachanic]

Describe the bug

If an exception generated by mssql-python is pickled, the following error will occur on unpickle:
[error].__init__() missing 1 required positional argument: 'ddbc_error'

This causes issues when using e.g. multiprocessing and attempting to marshal errors back to a central process.

To reproduce

import mssql_python, pickle

conn = mssql_python.connect("conn_string_here")
cur = conn.cursor()
try:
    cur.execute('insert into fake_tbl values (123)')
except Exception as e:
    d = pickle.dumps(e)

ex = pickle.loads(d)

Expected behavior

The pickled exception should cleanly unpickle, and then I should be able to treat it just like any other exception object.

Further technical details

Python version: 3.12.3
SQL Server version: N/A
Operating system: N/A

[github-actions]

Hi @amachanic, thank you for opening this issue!

Our team will review it shortly. We aim to triage all new issues within 24-48 hours and get back to you.

If you have additional information to share, please feel free to update the issue.

Thank you for your patience!

[bewithgaurav]

Thanks for the report, @amachanic, confirmed the repro. The exception classes aren't round-tripping through pickle cleanly, which is why multiprocessing (and similar) chokes on them. We'll get a fix up shortly and link this PR.
Thanks again, will keep this posted.