cloning bug in select

[Mike Bayer]

#!/usr/bin/env python
# encoding: utf-8

# This is an illustration of a problem with column_properties where
# the from_obj contains joined aliased tables.

from sqlalchemy import Table, Column, Integer, ForeignKey, MetaData
from sqlalchemy import select
from sqlalchemy.sql.util import _deep_deannotate

metadata = MetaData()

orders = Table(
    'orders', metadata,
    Column('order_id', Integer, primary_key=True),
)

item = Table(
    'item', metadata,
    Column('item_id', Integer, primary_key=True),
    Column('order_id', Integer, ForeignKey('orders.order_id')),
)

a = item
b = a.outerjoin(orders)
s = select([a.c.item_id](a.c.item_id), from_obj=b)

a = item.alias()
b = a.outerjoin(orders)
s = select([a.c.item_id](a.c.item_id), from_obj=b)

print s
# XXX Not OK. Look at the FROM clause of this select
print _deep_deannotate(s)

[Mike Bayer]

patch:

diff -r 7142a17291deba2eb9d4a2b30e1635129c2284ea lib/sqlalchemy/sql/expression.py
--- a/lib/sqlalchemy/sql/expression.py  Wed Mar 21 22:58:55 2012 -0400
+++ b/lib/sqlalchemy/sql/expression.py  Fri Mar 30 09:45:30 2012 -0400
@@ -4800,10 +4800,22 @@
         """
         froms = self._froms

+        # FROM objects that are being replaced by something else,
+        # typically a JOIN involving that FROM
         toremove = set(itertools.chain(*[for f in froms](f._hide_froms)))
         if toremove:
+            # if we're maintaining clones of froms,
+            # add the copies out to the toremove list
+            if self._from_cloned:
+                toremove.update(
+                    self._from_cloned[f](f) for f in 
+                    toremove.intersection(self._from_cloned)
+                )
+            # filter out to FROM clauses not in the list,
+            # using a list to maintain ordering
             froms = [for f in froms if f not in toremove](f)

+
         if len(froms) > 1 or self._correlate:
             if self._correlate:
                 froms = [f for f in froms if f not in _cloned_intersection(froms,

[Mike Bayer]

this was addressed instead at the annotation level, by maintaining a unique copy of the Alias instead of multiple. 45046367f34ee2dadb98024b0f2b05248459f978

[Mike Bayer]

OK we still need to do that extra "toremove" logic for the case where _deep_deannotates are nested....

mytable2 = table2.alias()

s = select(
    [       _deep_deannotate(
            select(
                [
                    _deep_deannotate(
                        select(
                            [ mytable2.c.t2_id ](
),
                            from_obj=table1.join(mytable2)
                        ).as_scalar()
                    ),
                ]
            ).as_scalar()
        )
    ],
)

which would be if you're nesting column_property() objs together

another razor thin edge ..

[Mike Bayer]

okey doke 1378bf0d25319f3725cfe8ff947a5f0aeae4cc81

[Mike Bayer]

Removing milestone: 0.7.7 (automated comment)