AttributeError: 'bool' object has no attribute 'strftime' - odoo

Question

I am inheriting 'account.partner.ledger' module. When we select the customer we will be able to print the report of the customer's ledger. In the partner ledger menu I want to make 'include Initial Balances' checkbox checked by default if the filter is by date/period.I tried to override the method by my custom module but I am unable to solve the error which I am getting.
Code,
#api.multi
def onchange_filter(self,filter='filter_no', fiscalyear_id=False):
res = super(account_partner_ledger, self).onchange_filter(filter=filter, fiscalyear_id=fiscalyear_id)
if filter in ['filter_no', 'unreconciled']:
if filter == 'unreconciled':
res['value'].update({'fiscalyear_id': False})
res['value'].update({'initial_balance': False, 'period_from': False, 'period_to': False, 'date_from': False ,'date_to': False})
if filter in ['filter_date','filter_period']:
res['value'].update({'initial_balance': True, 'period_from': True, 'period_to': True, 'date_from': True ,'date_to': True})
return res
Error,
Traceback (most recent call last):
File "C:\Users\zendynamix\odooGit\odoo8\openerp\http.py", line 544, in _handle_exception
return super(JsonRequest, self)._handle_exception(exception)
File "C:\Users\zendynamix\odooGit\odoo8\openerp\http.py", line 581, in dispatch
result = self._call_function(**self.params)
File "C:\Users\zendynamix\odooGit\odoo8\openerp\http.py", line 317, in _call_function
return checked_call(self.db, *args, **kwargs)
File "C:\Users\zendynamix\odooGit\odoo8\openerp\service\model.py", line 118, in wrapper
return f(dbname, *args, **kwargs)
File "C:\Users\zendynamix\odooGit\odoo8\openerp\http.py", line 314, in checked_call
return self.endpoint(*a, **kw)
File "C:\Users\zendynamix\odooGit\odoo8\openerp\http.py", line 810, in __call__
return self.method(*args, **kw)
File "C:\Users\zendynamix\odooGit\odoo8\openerp\http.py", line 410, in response_wrap
response = f(*args, **kw)
File "C:\Users\zendynamix\odooGit\odoo8\addons\web\controllers\main.py", line 944, in call_kw
return self._call_kw(model, method, args, kwargs)
File "C:\Users\zendynamix\odooGit\odoo8\addons\web\controllers\main.py", line 936, in _call_kw
return getattr(request.registry.get(model), method)(request.cr, request.uid, *args, **kwargs)
File "C:\Users\zendynamix\odooGit\odoo8\openerp\api.py", line 268, in wrapper
return old_api(self, *args, **kwargs)
File "C:\Users\zendynamix\odooGit\odoo8\openerp\api.py", line 399, in old_api
result = method(recs, *args, **kwargs)
File "C:\Users\zendynamix\odooGit\odoo8\openerp\models.py", line 5985, in onchange
record._onchange_eval(name, field_onchange[name], result)
File "C:\Users\zendynamix\odooGit\odoo8\openerp\models.py", line 5883, in _onchange_eval
self.update(self._convert_to_cache(method_res['value'], validate=False))
File "C:\Users\zendynamix\odooGit\odoo8\openerp\models.py", line 5391, in _convert_to_cache
for name, value in values.iteritems()
File "C:\Users\zendynamix\odooGit\odoo8\openerp\models.py", line 5392, in <dictcomp>
if name in fields
File "C:\Users\zendynamix\odooGit\odoo8\openerp\fields.py", line 1250, in convert_to_cache
return self.to_string(value)
File "C:\Users\zendynamix\odooGit\odoo8\openerp\fields.py", line 1240, in to_string
return value.strftime(DATE_FORMAT) if value else False
AttributeError: 'bool' object has no attribute 'strftime'

Answer 1

You have to look at the underlying code sometimes to understand what's going on, you're getting errors because Odoo is trying to convert a boolean object back to a string representation of a time (it expects a python date object)
You can fire up a terminal and reproduce your error:
>>> True.strftime
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
AttributeError: 'bool' object has no attribute 'strftime'
>>>
This is the to_string method from odoo
#staticmethod
def to_string(value):
""" Convert a :class:`date` value into the format expected by the ORM. """
return value.strftime(DATE_FORMAT) if value else False
The test condition if value test's to see if value evaluates to False, testing from the terminal
>>> x = ''
>>> if x: print('Yeah')
...
>>>
>>> x = True
>>> if x: print('Yeah')
...
Yeah
>>> x = False
>>> if x: print('Yeah')
...
>>>
>>>
from the output, we can draw a conclusion that an empty string or False evaluates to False while a True value will evaluate to True, so instead of setting the date values to True, set all of them to empty strings.
#api.multi
def onchange_filter(self,filter='filter_no', fiscalyear_id=False):
res = super(account_partner_ledger, self).onchange_filter(filter=filter, fiscalyear_id=fiscalyear_id)
if filter in ['filter_no', 'unreconciled']:
if filter == 'unreconciled':
res['value'].update({'fiscalyear_id': False})
res['value'].update({'initial_balance': False, 'period_from': False, 'period_to': False, 'date_from': False ,'date_to': False})
if filter in ['filter_date','filter_period']:
res['value'].update({'initial_balance': 'True', 'period_from': '', 'period_to': '', 'date_from': '', 'date_to': ''})
return res

Answer 2

When you look at your code you'll see:
'date_from': True ,'date_to': True
This causes your error.
You should set those fields to a date not to a Boolean.
The value False is valid, since you should be able to not fill in a date.

Answer 3

Try using strptime instead of strftime and see if it solves the problem.
You can use strptime as follows for example:-
from openerp.tools import DEFAULT_SERVER_DATETIME_FORMAT
my_date = datetime.strptime(self.date_column, DEFAULT_SERVER_DATETIME_FORMAT)