[Sqlalchemy-tickets] Issue #2965: foreign_keys logic with overlapping composite foreign keys (zzzeek/sqlalchemy)

[Mike B. <iss...@bi...>]

New issue 2965: foreign_keys logic with overlapping composite foreign keys
https://bitbucket.org/zzzeek/sqlalchemy/issue/2965/foreign_keys-logic-with-overlapping

Mike Bayer:


```
#!python

from sqlalchemy import *

from sqlalchemy.ext.declarative import declarative_base

from sqlalchemy.orm import *


Base = declarative_base()

class User(Base):
    __tablename__ = "user"
    uid = Column(String(600), primary_key=True)
    oid = Column(String(100), primary_key=True)
    name = Column(String(600), nullable=False)
    lastname = Column(String(600), nullable=False)

class Bet(Base):
    __tablename__ = "bet"
    __table_args__ = (
       ForeignKeyConstraint(("uid", "oid"), ("user.uid", "user.oid")),
       ForeignKeyConstraint(("loader_uid", "oid"), ("user.uid", "user.oid")),
    )
    id = Column(Integer, autoincrement=True, primary_key=True)
    uid = Column(String(600), nullable=False)
    oid = Column(String(100), nullable=False)

    runner = relationship("User",
                     # passes
                     #primaryjoin="and_(foreign(Bet.uid)==User.uid, foreign(Bet.oid)==User.oid)",

                     # fails
                     foreign_keys=[loader_uid, oid]
                     )
    loader = relationship("User",
                     # passes
                     #primaryjoin="and_(foreign(Bet.loader_uid)==User.uid, foreign(Bet.oid)==User.oid)",

                      # fails
                     foreign_keys=[loader_uid, oid]
                        )


```