Update_fields does not work on a field initially set to None

[bip91]

Hi,

in a Sharepoint list, if we have a field that is not initially set, it is not possible to update it to a new value.

Context :
i = l.get_item_by_id(x)
i.fields # > does not contain any "Status" field as "Status" is not set for this item
i._parent.column_name_cw.value() # > but this contain "Status" value

in that case, update_field raise an error :

i.update_fields({'Status': 'Inactif'})
Traceback (most recent call last):
File "", line 1, in
File "/home/bruno/src/o365/lib/python3.12/site-packages/O365/sharepoint.py", line 154, in update_fields
raise ValueError('"{}" is not a valid internal field name'.format(field))

Explanation :
This is due to the fact that self.fields exists, but not contains the field,
and second condition is never tested.

def _valid_field(self, field):
    # Verify the used field names are valid internal field names
    valid_field_names = self.fields if self.fields \
        else self._parent.column_name_cw.values() \
        if self._parent \
        else None
    if valid_field_names:
        return field in valid_field_names

Solution:
I would suggest to switch the 2 conditions like this :

def _valid_field(self, field):
    # Verify the used field names are valid internal field names
    valid_field_names = self._parent.column_name_cw.values() if self._parent \
                        else self.fields if self.fields \
                        else None
    
    # If no parent is given, and no internal fields are defined assume correct, API will check
    if valid_field_names is None:
        return True
    
    return field in valid_field_names

[alejcas]

Is it posible to have a field in self.fields that is not in self._parent.column_name_cw.values()?

[bip91]

I don't see any usual case, except perhaps when a field is added.

I have always seen at least self.fields or parent.column_name set
but self.fields contain only fields that have values in Sharepoint list record.
(A bit annoying to rely on that if we want to set a such field).

[alejcas]

Can you make a PR with this changes?
Thanks