A dependency is not considered satisfied if it has a null value

[derek-miller]

Used Cerberus version / latest commit: 1.1

• I consulted these documentations:

  • http://docs.python-cerberus.org/en/stable/
  • http://docs.python-cerberus.org/en/latest/

• I consulted these sections of the docs (add more lines as necessary):

  • http://docs.python-cerberus.org/en/stable/validation-rules.html#dependencies

• I found nothing relevant to my problem in the docs.

• I found the documentation not helpful to my problem.

• I have the capacity to improve the docs when my problem is solved.

• I have the capacity to submit a patch when a bug is identified.

---

Use-case abstract

A dependency is not considered satisfied if it has a null value.

---

Support request / Bug report

To reproduce:

>>> from cerberus import Validator
... validator = Validator(schema={
...     'field1': {
...         'required': False,
...         'nullable': True
...     },
...     'field2': {
...         'required': False,
...         'dependencies': 'field1'
...     }
... })
... document = {
...     'field1': None,
...     'field2': 'foo'
... }
... assert validator.validate(document), validator.errors
Traceback (most recent call last):
  File "<input>", line 16, in <module>
AssertionError: {'field2': ["field 'field1' is required"]}

This seems wrong considering required fields with a null value satisfy the required constraint, but not a dependency.

[funkyfuture]

does it also behave that way when defined without dependency?

my suspicion is that what you observe is rooted here.

if a field that is defined as required shall also fail when its value is None (my guess for now would be that this is intended), that fact should be amended to the docs.

[derek-miller]

No, a required field with a null value satisfies the required rule:

>>> from cerberus import Validator
... validator = Validator(schema={
...     'field1': {
...         'required': True,
...         'nullable': True
...     },
...     'field2': {
...         'required': False,
...         #'dependencies': 'field1'
...     }
... })
... document = {
...     'field1': None,
...     'field2': 'foo'
... }
>>> assert validator.validate(document), validator.errors
>>>