[Sqlalchemy-tickets] Issue #3248: populate_result_map gets set for select() that's in the VALUES of an insert() (zzzeek/sqlalchemy)

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

New issue 3248: populate_result_map gets set for select() that's in the VALUES of an insert()
https://bitbucket.org/zzzeek/sqlalchemy/issue/3248/populate_result_map-gets-set-for-select

Mike Bayer:


```
#!python

from sqlalchemy import *

class MyType(TypeDecorator):
    impl = Integer

    def process_result_value(self, value, dialect):
        raise Exception("I have not been selected")

m1 = MetaData()
t1 = Table('t1', m1,
    Column('x', MyType())
)

t2 = Table('t2', m1,
    Column('x', Integer)
)

e = create_engine("postgresql://scott:tiger@localhost/test", echo='debug')
m1.drop_all(e)
m1.create_all(e)

e.execute(t1.insert().values(x=5))

stmt = t2.insert().values(x=select([t1.c.x]).as_scalar()).returning(t2.c.x)

result = e.execute(stmt)
result.scalar()

```


```
#!

Traceback (most recent call last):
  File "test2.py", line 27, in <module>
    result.scalar()
  File "/Users/classic/dev/sqlalchemy/lib/sqlalchemy/engine/result.py", line 888, in scalar
    return row[0]
  File "/Users/classic/dev/sqlalchemy/lib/sqlalchemy/engine/result.py", line 90, in __getitem__
    return processor(self._row[index])
  File "/Users/classic/dev/sqlalchemy/lib/sqlalchemy/sql/type_api.py", line 915, in process
    return process_value(value, dialect)
  File "test2.py", line 7, in process_result_value
    raise Exception("I have not been selected")
Exception: I have not been selected

```