Phillip J. Eby wrote:
> At 02:26 PM 3/27/2008 -0700, jason kirtland wrote:
>>>> new_instance creates an instance without invoking __init__. The ORM
>>>> uses it to recreate instances when loading from the database.
>>>> new_instance can be added to InstrumentationManager as an extension
>>>> method... The ORM doesn't care how empty instances are manufactured so
>>>> long as they can be created without initialization arguments, e.g. a
>>>> no-arg constructor.
>>> Does that mean that no attributes must be set from new_instance(), either?
>> You should be able to set whatever you like there.
>
> So... new_instance() could literally just be a call to
> 'self.class_()', with no other behavior, as long as the constructor
> requires no arguments? The modified __init__ that SA inserts won't
> be a problem there?
Sorry, I should have included more detail. You don't want to trigger
the logic in SA's __init__ decorator or call the user's __init__. The
ORM policy is not to __init__ on load, and will soon support a symmetric
"__on_load__" type of hook that the ORM can call post-__new__ when
reconstituting instances.
The docstring from attributes.new_instance hasn't yet been copied to the
new ClassManager method it now delegates to, but the existing contract
is still the guide here:
def new_instance(class_, state=None):
"""Create a new instance of class_ without calling __init__()."""
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