Setter does not behave as it should.

[cenouro]

import mongoengine as me

class Product(me.Document):
    price = me.DecimalField(force_string=True, precision=2)

p = Product(price=10.50)
p.to_mongo()
# >> SON([('price', '10.50')])

p = Product()
p.price = 10.50
p.to_mongo()
# >> SON([('price', '10.5')])

Am I doing something wrong?

[touilleMan]

Hi,
I've created an unittest that show the bug (see touilleMan@bc7b4a9)

From my point of view, the trouble is when price is passed during document creation, it is altered by Product.price.to_python before being set.
On the other hand, using p.price = 10.50 means p.price is a regular float

>>> p = Product(price=10.50).save()
>>> type(p.btc)
<class 'decimal.Decimal'>
>>> p.price = 10.50
>>> p.save()
>>> type(p.btc)
builtins.float

I guess we should overload Document setter to call to_python

[touilleMan]

I've pushed a first quick fix to use to_python in BaseDocument.__setattr__ (see touilleMan@a3919ef)

Plenty of tests are broken with this, but I'm wondering if this doesn't hide a bigger refactoring need, see for example:

511         def test_boolean_validation(self):
512             """Ensure that invalid values cannot be assigned to boolean fields.
513             """
514             class Person(Document):
515                 admin = BooleanField()
516     
517             person = Person()
518             person.admin = True
519             person.validate()
520     
521             person.admin = 2
522  ->         self.assertRaises(ValidationError, person.validate)  # My fix makes the test break here
523             person.admin = 'Yes'
524             self.assertRaises(ValidationError, person.validate)
(Pdb) person.admin  # admin field has been converted by my `to_python` from an `int` to a `boolean`...
True
(Pdb) Person(admin=2).admin  # ...but it's already the behaviour when giving a field at creation time !
True

[cenouro]

Could you add this to your test case?

    Person(admin=[]).admin   
    # if this returns False, then the problem is python's duck-typing

If the problem is indeed Python's duck-typing, then a good feature would be to implement a more restrictive 'type casting' on the BooleanField class (and other *Field classes for that matter).