#25177: Filter reference field on model to a date difference raise a TypeError
----------------------------------------------+--------------------
Reporter: MounirMesselmeni | Owner: nobody
Type: Bug | Status: new
Component: Database layer (models, ORM) | Version: 1.8
Severity: Normal | Keywords:
Triage Stage: Unreviewed | Has patch: 0
Easy pickings: 0 | UI/UX: 0
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I want to filter all products that the start_date and signed_date are
lesser than or equal than a specific value.
Before 1.7, I was doing the following:
{{{
Product.objects.filter(start_date__isnull=False).extra(
where=['"appname_product"."start_date" -
"appname_product"."signed_date" <= %s' % days],
).count()
}}}
Now, I tried to do the following using F expressions:
{{{
Product.objects.filter(start_date__isnull=False).annotate(days=F('start_date')-F('signed_date')).filter(days__lte=days)
}}}
The problem, this will raise a TypeError because I think it will try to
parse the value to Date:
{{{
/usr/local/lib/python2.7/dist-packages/django/db/models/query.pyc in
filter(self, *args, **kwargs)
677 set.
678 """
--> 679 return self._filter_or_exclude(False, *args, **kwargs)
680
681 def exclude(self, *args, **kwargs):
/usr/local/lib/python2.7/dist-packages/django/db/models/query.pyc in
_filter_or_exclude(self, negate, *args, **kwargs)
695 clone.query.add_q(~Q(*args, **kwargs))
696 else:
--> 697 clone.query.add_q(Q(*args, **kwargs))
698 return clone
699
/usr/local/lib/python2.7/dist-packages/django/db/models/sql/query.pyc in
add_q(self, q_object)
1307 existing_inner = set(
1308 (a for a in self.alias_map if
self.alias_map[a].join_type == INNER))
-> 1309 clause, require_inner = self._add_q(where_part,
self.used_aliases)
1310 self.where.add(clause, AND)
1311 for hp in having_parts:
/usr/local/lib/python2.7/dist-packages/django/db/models/sql/query.pyc in
_add_q(self, q_object, used_aliases, branch_negated, current_negated,
allow_joins, split_subq)
1335 child, can_reuse=used_aliases,
branch_negated=branch_negated,
1336 current_negated=current_negated,
connector=connector,
-> 1337 allow_joins=allow_joins,
split_subq=split_subq,
1338 )
1339 joinpromoter.add_votes(needed_inner)
/usr/local/lib/python2.7/dist-packages/django/db/models/sql/query.pyc in
build_filter(self, filter_expr, branch_negated, current_negated,
can_reuse, connector, allow_joins, split_subq)
1157 clause = self.where_class()
1158 if reffed_expression:
-> 1159 condition = self.build_lookup(lookups,
reffed_expression, value)
1160 if not condition:
1161 # Backwards compat for custom lookups
/usr/local/lib/python2.7/dist-packages/django/db/models/sql/query.pyc in
build_lookup(self, lookups, lhs, rhs)
1099 lhs = self.try_transform(lhs, name, lookups)
1100 final_lookup = lhs.get_lookup('exact')
-> 1101 return final_lookup(lhs, rhs)
1102 lhs = self.try_transform(lhs, name, lookups)
1103 lookups = lookups[1:]
/usr/local/lib/python2.7/dist-packages/django/db/models/lookups.pyc in
__init__(self, lhs, rhs)
99 def __init__(self, lhs, rhs):
100 self.lhs, self.rhs = lhs, rhs
--> 101 self.rhs = self.get_prep_lookup()
102 if hasattr(self.lhs, 'get_bilateral_transforms'):
103 bilateral_transforms =
self.lhs.get_bilateral_transforms()
/usr/local/lib/python2.7/dist-packages/django/db/models/lookups.pyc in
get_prep_lookup(self)
137
138 def get_prep_lookup(self):
--> 139 return
self.lhs.output_field.get_prep_lookup(self.lookup_name, self.rhs)
140
141 def get_db_prep_lookup(self, value, connection):
/usr/local/lib/python2.7/dist-
packages/django/db/models/fields/__init__.pyc in get_prep_lookup(self,
lookup_type, value)
1311 if lookup_type in ('month', 'day', 'week_day', 'hour',
'minute', 'second'):
1312 return int(value)
-> 1313 return super(DateField, self).get_prep_lookup(lookup_type,
value)
1314
1315 def get_prep_value(self, value):
/usr/local/lib/python2.7/dist-
packages/django/db/models/fields/__init__.pyc in get_prep_lookup(self,
lookup_type, value)
725 return value
726 elif lookup_type in ('exact', 'gt', 'gte', 'lt', 'lte'):
--> 727 return self.get_prep_value(value)
728 elif lookup_type in ('range', 'in'):
729 return [self.get_prep_value(v) for v in value]
/usr/local/lib/python2.7/dist-
packages/django/db/models/fields/__init__.pyc in get_prep_value(self,
value)
1315 def get_prep_value(self, value):
1316 value = super(DateField, self).get_prep_value(value)
-> 1317 return self.to_python(value)
1318
1319 def get_db_prep_value(self, value, connection,
prepared=False):
/usr/local/lib/python2.7/dist-
packages/django/db/models/fields/__init__.pyc in to_python(self, value)
1272
1273 try:
-> 1274 parsed = parse_date(value)
1275 if parsed is not None:
1276 return parsed
/usr/local/lib/python2.7/dist-packages/django/utils/dateparse.pyc in
parse_date(value)
58 Returns None if the input isn't well formatted.
59 """
---> 60 match = date_re.match(value)
61 if match:
62 kw = {k: int(v) for k, v in
six.iteritems(match.groupdict())}
TypeError: expected string or buffer
}}}
--
Ticket URL: <https://code.djangoproject.com/ticket/25177>
Django <https://code.djangoproject.com/>
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