[Sqlalchemy-tickets] Issue #3367: sqlalchemy 1.0.0 does not allow specifying a join more than once (zzzeek/sqlalchemy)

[Charles-Axel D. <iss...@bi...>]

New issue 3367: sqlalchemy 1.0.0 does not allow specifying a join more than once
https://bitbucket.org/zzzeek/sqlalchemy/issue/3367/sqlalchemy-100-does-not-allow-specifying-a

Charles-Axel Dein:

I'm upgrading a codebase to sqlalchemy 1.0.0beta5  from 0.9.9.

It seems that version 1 removed the ability to be forgiving about mentioning a join twice:

```
session.query(Toaster).join(Toast).join(Toast).all()
```

This will raise with postgres: `ProgrammingError: (psycopg2.ProgrammingError) table name "financing_statuses" specified more than once`

The same query run with sqla 0.9.9 runs fine, because I guess it removes the duplicate join.

I'm not sure that can be considered a regression given that joins should not be mentioned more than once, but it's definitely a different behavior from 0.9.9