[Sqlalchemy-tickets] Issue #3844: passive_deletes='all' is not complete (zzzeek/sqlalchemy)

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

New issue 3844: passive_deletes='all' is not complete
https://bitbucket.org/zzzeek/sqlalchemy/issues/3844/passive_deletes-all-is-not-complete

Michael Bayer:

Probably has to wait until 1.2 because this is a behavior change, but passive_deletes is not skipping setting the FK to NULL in all cases:


```
#!python

from sqlalchemy import Column, Integer, String, ForeignKey, Boolean
from sqlalchemy import create_engine, and_
from sqlalchemy.ext.declarative import declarative_base
from sqlalchemy.orm import relationship
from sqlalchemy.orm import sessionmaker
from sqlalchemy import event
from sqlalchemy import inspect

Base = declarative_base()
engine = create_engine('sqlite:///:memory:', echo=True)
Session = sessionmaker(bind=engine)


class User(Base):
    __tablename__ = 'users'

    id = Column(Integer, primary_key=True)
    address = relationship(
        "Address",
        uselist=False,
        passive_deletes="all")


class Address(Base):
    __tablename__ = 'addresses'
    id = Column(Integer, primary_key=True)
    email = Column(String, nullable=False)
    deleted = Column(Boolean, nullable=False, default=False)

    user_id = Column(Integer, ForeignKey('users.id'))
    user = relationship("User")

Base.metadata.create_all(engine)
sess = Session()

a1 = Address(email='foo')
u = User(id=1, address=a1)
sess.add_all([u, a1])
sess.commit()

u.address = Address(email='bar')
sess.commit()

assert a1.user_id == 1, a1.user_id


```

because we have a sync to None not checking it, needs this:

```
#!diff


diff --git a/lib/sqlalchemy/orm/dependency.py b/lib/sqlalchemy/orm/dependency.py
index a3e5b12..f2193b6 100644
--- a/lib/sqlalchemy/orm/dependency.py
+++ b/lib/sqlalchemy/orm/dependency.py
@@ -553,7 +553,8 @@ class OneToManyDP(DependencyProcessor):
 
                 for child in history.deleted:
                     if not self.cascade.delete_orphan and \
-                            not self.hasparent(child):
+                            not self.hasparent(child) and \
+                            not self.passive_deletes == 'all':
                         self._synchronize(state, child, None, True,
                                           uowcommit, False)
 

```

check if this bug is a dupe b.c. this seems kind of obvious, also check for any other synchronize(.. None) that is being allowed.  review the docs for passive_deletes to make sure I'm not misunderstanding the intent.

making this critical so it remains noticed.