Multiplying CASE statement by field generates TypeError: can only concatenate list (not "itertools.chain") to list

[Former user]

The following code works under 0.5.2 but produces an error under 0.5.3:

from sqlalchemy import Table, Column, Integer, MetaData, create_engine, case, select

engine = create_engine('sqlite:///:memory:')

metadata = MetaData()
users_table = Table('users', metadata,
     Column('id', Integer, primary_key=True),
     Column('foo', Integer),
)

metadata.create_all(engine)

print select([(users_table.c.foo)*case([(users_table.c.id>10, 1), (users_table.c.id<10, 2)](users_table.c.id,))])

The desired SQL is:

SELECT users.id, users.foo * CASE WHEN (users.id > 10) THEN 1 WHEN (users.id < 10) THEN 2 END AS anon_1
FROM users

[Former user]

Can you post the full stack trace?

[Former user]

The test code is self contained and can be run by simply pasting it into a file. The traceback is:

Traceback (most recent call last):
  File "error_test.py", line 13, in <module>
    print select([(users_table.c.foo)*case([(users_table.c.id>10, 1), (users_table.c.id<10, 2)](users_table.c.id,))])
  File "/usr/lib/python2.5/site-packages/SQLAlchemy-0.5.3-py2.5.egg/sqlalchemy/sql/expression.py", line 246, in select
    s = Select(columns, whereclause=whereclause, from_obj=from_obj, **kwargs)
  File "/usr/lib/python2.5/site-packages/SQLAlchemy-0.5.3-py2.5.egg/sqlalchemy/sql/expression.py", line 3218, in __init__
    self._froms.update(_from_objects(*self._raw_columns))
  File "/usr/lib/python2.5/site-packages/SQLAlchemy-0.5.3-py2.5.egg/sqlalchemy/sql/expression.py", line 886, in _from_objects
    return itertools.chain(*[for element in elements](element._from_objects))
  File "/usr/lib/python2.5/site-packages/SQLAlchemy-0.5.3-py2.5.egg/sqlalchemy/sql/expression.py", line 2384, in _from_objects
    return self.left._from_objects + self.right._from_objects
TypeError: can only concatenate list (not "itertools.chain") to list

[Mike Bayer]

this works in current trunk (pre-0.5.4).

[Mike Bayer]

Removing milestone: 0.5.4 (automated comment)