same named relationship from two subclasses cant be targeted

[sqlalchemy-bot]

Migrated issue, originally created by Michael Bayer (@zzzeek)

due to the path reduction. a simple switch to use non-reduce paths fails to even initiate the eagerload at all.

from sqlalchemy.ext.declarative import declarative_base
from sqlalchemy import *
from sqlalchemy.orm import relationship, subqueryload, Session

Base = declarative_base()

class A(Base):
    __tablename__ = 'a'
    id = Column(Integer, primary_key=True)
    type = Column(String)

    __mapper_args__ = {'polymorphic_on': type}

class B(A):
    __tablename__ = 'b'
    id = Column(Integer, ForeignKey('a.id'), primary_key=True)

    btod = Table('btod', Base.metadata,
        Column('bid', Integer, ForeignKey('b.id'), nullable=False),
        Column('did', Integer, ForeignKey('d.id'), nullable=False)
    )
    related = relationship("D", secondary=btod)
    __mapper_args__ = {'polymorphic_identity': 'b'}

class C(A):
    __tablename__ = 'c'
    id = Column(Integer, ForeignKey('a.id'), primary_key=True)
    ctod = Table('ctod', Base.metadata,
        Column('cid', Integer, ForeignKey('c.id'), nullable=False),
        Column('did', Integer, ForeignKey('d.id'), nullable=False)
    )
    related = relationship("D", secondary=ctod)
    __mapper_args__ = {'polymorphic_identity': 'c'}

class D(Base):
    __tablename__ = 'd'
    id = Column(Integer, primary_key=True)

engine = create_engine('sqlite://', echo=True)
Base.metadata.create_all(engine)
session = Session(engine)

d = D()
session.add_all([   B(related=[d](
)),
    C(related=[d](d))
])
session.commit()

for a in session.query(A).with_polymorphic('*').\
        options(subqueryload(B.related), subqueryload(C.related)):
    print a.related

---

Attachments: 2614.patch

[sqlalchemy-bot]

Michael Bayer (@zzzeek) wrote:

this is the workaround people can use who really need this pattern:

class A(..):
    myChildrenA = relationship(...)

   @property
   def myChildren(self):
        return myChildrenA

class B(..):
    myChildrenB = relationship(...)

   @property
   def myChildren(self):
        return myChildrenB

[sqlalchemy-bot]

Michael Bayer (@zzzeek) wrote:

here's the beginning of a patch but this messes up a lot of tests. so this is a big rethink kind of issue, as we've not tried to figure out how to target those paths more accurately as of yet.

diff -r 0f0ce7c9b7c4b3a9f1329dfa9c42d0d69386d48f lib/sqlalchemy/orm/interfaces.py
--- a/lib/sqlalchemy/orm/interfaces.py  Thu Nov 22 23:45:24 2012 -0500
+++ b/lib/sqlalchemy/orm/interfaces.py  Fri Nov 23 17:15:28 2012 -0500
@@ -414,7 +414,7 @@

     def _get_context_strategy(self, context, path):
         # this is essentially performance inlining.
-        key = ('loaderstrategy', path.reduced_path + (self.key,))
+        key = ('loaderstrategy', path.path + (self.key,))
         cls = None
         if key in context.attributes:
             cls = context.attributes[key](key)
@@ -648,7 +648,8 @@
                                             raiseerr)
                     if not entity:
                         return no_result
-                    path_element = entity.entity_zero
+                    path_element = token._parententity
+                    #path_element = entity.entity_zero
                     mapper = entity.mapper
             else:
                 raise sa_exc.ArgumentError(
diff -r 0f0ce7c9b7c4b3a9f1329dfa9c42d0d69386d48f lib/sqlalchemy/orm/query.py
--- a/lib/sqlalchemy/orm/query.py   Thu Nov 22 23:45:24 2012 -0500
+++ b/lib/sqlalchemy/orm/query.py   Fri Nov 23 17:15:28 2012 -0500
@@ -2882,7 +2882,7 @@
             value.setup(
                 context,
                 self,
-                self.path,
+                value.parent._sa_path_registry,  # self.path,
                 adapter,
                 only_load_props=query._only_load_props,
                 column_collection=context.primary_columns
diff -r 0f0ce7c9b7c4b3a9f1329dfa9c42d0d69386d48f lib/sqlalchemy/orm/strategies.py
--- a/lib/sqlalchemy/orm/strategies.py  Thu Nov 22 23:45:24 2012 -0500
+++ b/lib/sqlalchemy/orm/strategies.py  Fri Nov 23 17:15:28 2012 -0500
@@ -679,7 +679,6 @@
                         path, adapter,
                         column_collection=None,
                         parentmapper=None, **kwargs):
-
         if not context.query._enable_eagerloads:
             return

diff -r 0f0ce7c9b7c4b3a9f1329dfa9c42d0d69386d48f lib/sqlalchemy/orm/util.py
--- a/lib/sqlalchemy/orm/util.py    Thu Nov 22 23:45:24 2012 -0500
+++ b/lib/sqlalchemy/orm/util.py    Fri Nov 23 17:15:28 2012 -0500
@@ -277,13 +277,13 @@
             self.path == other.path

     def set(self, reg, key, value):
-        reg._attributes[self.reduced_path)]((key,) = value
+        reg._attributes[self.path)]((key,) = value

     def setdefault(self, reg, key, value):
-        reg._attributes.setdefault((key, self.reduced_path), value)
+        reg._attributes.setdefault((key, self.path), value)

     def get(self, reg, key, value=None):
-        key = (key, self.reduced_path)
+        key = (key, self.path)
         if key in reg._attributes:
             return reg._attributes[key](key)
         else:
@@ -300,7 +300,7 @@
         return mapper in self.path

     def contains(self, reg, key):
-        return (key, self.reduced_path) in reg._attributes
+        return (key, self.path) in reg._attributes

     def serialize(self):
         path = self.path

[sqlalchemy-bot]

Michael Bayer (@zzzeek) wrote:

partial patch to start allowing more accurate path in query.setup

[sqlalchemy-bot]

Michael Bayer (@zzzeek) wrote:

the attached patch attempts to get _MapperEntity.setup_context() to pass accurate pathing information to value.setup(). It requires changes to AliasedClass in that the AC needs to carry along the with_polymorphic of the parent mapper, as well as that an AC like Person.Engineer needs to "reduce" down to Person. Unfortunately, even with these adjustments, some very complex subqueryload tests are still failing, and this is only a small portion of the total change. Will attempt to emit a warning for this condition so that the release of 0.8 can continue.

[sqlalchemy-bot]

Michael Bayer (@zzzeek) wrote:

it's an exception raise, and it's in e2697d547ec8c24c9a37a72fc60abe73b7dee81b

[sqlalchemy-bot]

Michael Bayer (@zzzeek) wrote:

progress continues at https://bitbucket.org/zzzeek/sqla_2614

[sqlalchemy-bot]

Michael Bayer (@zzzeek) wrote:

going to try hitting this for 0.8final.

[sqlalchemy-bot]

Michael Bayer (@zzzeek) wrote:

b66dad46f31961ad9f2271e6dae377e38fc67979

[sqlalchemy-bot]

Changes by Michael Bayer (@zzzeek):

• attached file 2614.patch

[sqlalchemy-bot]

Changes by Michael Bayer (@zzzeek):

• changed milestone from "0.8.xx" to "0.8.0final"

[sqlalchemy-bot]

Changes by Michael Bayer (@zzzeek):

• changed status to closed