On Apr 10, 2013, at 5:10 AM, Alex Grönholm <[email protected]> wrote:
> The following class works on 0.8.0b2 but not 0.8.0 final:
>
> class EnumWrapper(SchemaType, TypeDecorator):
> def __init__(self, cls):
> kwargs = {'name': cls.__name__.lower()}
> self.impl = Enum(*(obj.key for obj in cls.values), **kwargs)
> self.wrapped = cls
>
> def _set_table(self, table, column):
> self.impl._set_table(table, column)
>
> def process_bind_param(self, value, dialect):
> if value is None:
> return None
> if isinstance(value, self.wrapped):
> return value.key
> elif isinstance(value, str):
> if value not in self.wrapped.symbols:
> raise TypeError('No such enum value in %s: %s' %
> (self.wrapped.__name__, value))
> return value
> raise TypeError('Expected %s, got %s instead' % (self.wrapped,
> type(value)))
>
> def process_result_value(self, value, dialect):
> return getattr(self.wrapped, value) if value is not None else None
>
> The error message ("TypeError: __init__() got an unexpected keyword argument
> 'schema'") originates from types.py, line 1886.
> Is inheriting from SchemaType still necessary? That is what seems to break
> things on 0.8.0 final.
Line 1886 of types.py, both in 0.8.0 and in tip, is this:
t.drop(bind=bind, checkfirst=checkfirst)
so that doesn't seem like the line we're referring to.
Since your example lacks context, I had to modify the call to "Enum" to use a
series of string names (don't know what obj.key, cls.values refer to). >From
there, I managed to get a stack trace that refers to line 1863 of types.py.
In the documentation for TypeDecorator at
http://docs.sqlalchemy.org/en/rel_0_8/core/types.html#sqlalchemy.types.TypeDecorator,
the example includes a copy() method. There is also a copy() method in the
original Enum recipe on my blog at
http://techspot.zzzeek.org/files/2011/decl_enum.py.
If the constructor of your decorated type is not compatible with the type
you're wrapping, you need to provide copy() as well:
def copy(self):
return DeclEnumType(self.wrapped)
hope this helps !
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