Outdated cookbook suggestion to use branched connections

[chrisjsewell]

Describe the bug

In https://alembic.sqlalchemy.org/en/latest/cookbook.html#sharing-a-connection-with-a-series-of-migration-commands-and-environments,
it gives a recipe using a branched connection.
However, as per Connection._branch:

deprecated:: 1.4 the "branching" concept will be removed in SQLAlchemy 2.0 as well as the "Connection.connect()" method which is the only consumer for this.

Expected behavior

The section would provide a "v2 compliant" solution

Thanks!

[zzzeek]

agree, the general idea is to just lose the "with connectable.connect()" part, it was trying to guess if the given "connection" were an Engine or Connection. no more guessing, it's a Connection. can accept a PR for this.

[chrisjsewell]

Thanks for the rapid response!
So to clarify, you feel there should be no side effects to just running with no context manager? (i.e. connection = connectable)

(p.s. just spent the last few hours watching your v2 YouTube tutorial; super helpful 🙏)

[zzzeek]

yup something like that, because the recipe has "with connctoin.begin()" on the outside of the alembic command as it is, you're already inside a transactional context