warn about unicode column having non-unicode default

[Former user]

foo = Column(Unicode(32), default="bar")

prints a warning when left at the default, and the source of this warning can be a pain to track down, as it only appears when the user's code doesn't specify a non-unicode value (ie, the default gets used).

If the library could detect the conflict of column type and default, and warn about it with a sane message when the model is loaded, that would be lovely

[Mike Bayer]

hey good idea. I was thinking why don't we just coerce, but yeah more consistent just treat it like the others.

[Former user]

from sqlalchemy.ext.declarative import declarative_base
from sqlalchemy import Table, Column, Integer, Unicode, create_engine

Base = declarative_base()

class Post(Base):
    __tablename__ = 'post'

    id = Column(Integer, primary_key=True)
    name = Column(Unicode(32), default=u'unicode_default')
    author = Column(Unicode(32), default='non_unicode_default')

    def __init__(self, id, name, author):
        self.id = id
        self.name = name
        self.author = author

engine = create_engine('sqlite://', echo=False)
Base.metadata.create_all(engine)




 SAWarning: Unicode column received non-unicode default value.
  author = Column(Unicode(32), default='non_unicode_default')

[Former user]

oops, not quite... there will be a part two to this patch.

[Former user]

With both patches applied in order, you get:

        if self.default is not None:
            if isinstance(self.default, (ColumnDefault, Sequence)):
                args.append(self.default)
            else:
                if getattr(self.type, '_warn_on_bytestring', False):
                    # Py3K
                    #if isinstance(self.default, bytes):
                    # Py2K
                    if isinstance(self.default, str):
                    # end Py2K
                        util.warn("Unicode column received non-unicode "
                                  "default value.")                    
                args.append(ColumnDefault(self.default))

Things I'm not sure about:

1. Does anything need to be done nuder this clause -- I know nothing yet about 'Sequence'

   if isinstance(self.default, (ColumnDefault, Sequence)):

2. Do these other checks I see elsewhere also need to happen in the above schema.py snippet:

       if self.convert_unicode or dialect.convert_unicode:
           if dialect.supports_unicode_binds and self.convert_unicode != 'force':
               ....
   

Thanks for letting me play along.

[Former user]

(original author: taavi) Fix in 3538e29a219e8e644d2f44c7f499571e5c1fae8e tests in 82ea44781985ce608185370a648db729de2cc2d9

[Mike Bayer]

Removing milestone: 0.7.0 (automated comment)