#34803: Nested OuterRef can raise AttributeError: 'OuterRef' object has no
attribute 'contains_over_clause'
-------------------------------------+-------------------------------------
Reporter: pierrenicolasr | Owner: nobody
Type: Bug | Status: new
Component: Database layer | Version: 4.2
(models, ORM) |
Severity: Normal | Resolution:
Keywords: | Triage Stage:
| Unreviewed
Has patch: 0 | Needs documentation: 0
Needs tests: 0 | Patch needs improvement: 0
Easy pickings: 0 | UI/UX: 0
-------------------------------------+-------------------------------------
Description changed by pierrenicolasr:
Old description:
> Porting our application from Django 3 to 4, we're seeing exception raised
> in complex queries using nested OuterRef
>
> {{{
> File "/usr/local/filewave/python/lib/python3.10/site-
> packages/django/db/models/query.py", line 1436, in filter
> return self._filter_or_exclude(False, args, kwargs)
> File "/usr/local/filewave/python/lib/python3.10/site-
> packages/django/db/models/query.py", line 1454, in _filter_or_exclude
> clone._filter_or_exclude_inplace(negate, args, kwargs)
> File "/usr/local/filewave/python/lib/python3.10/site-
> packages/django/db/models/query.py", line 1461, in
> _filter_or_exclude_inplace
> self._query.add_q(Q(*args, **kwargs))
> File "/usr/local/filewave/python/lib/python3.10/site-
> packages/django/db/models/sql/query.py", line 1545, in add_q
> clause, _ = self._add_q(q_object, self.used_aliases)
> File "/usr/local/filewave/python/lib/python3.10/site-
> packages/django/db/models/sql/query.py", line 1576, in _add_q
> child_clause, needed_inner = self.build_filter(
> File "/usr/local/filewave/python/lib/python3.10/site-
> packages/django/db/models/sql/query.py", line 1435, in build_filter
> value = self.resolve_lookup_value(value, can_reuse, allow_joins)
> File "/usr/local/filewave/python/lib/python3.10/site-
> packages/django/db/models/sql/query.py", line 1204, in
> resolve_lookup_value
> value = value.resolve_expression(
> File "/usr/local/filewave/python/lib/python3.10/site-
> packages/django/db/models/query.py", line 1923, in resolve_expression
> query = self.query.resolve_expression(*args, **kwargs)
> File "/usr/local/filewave/python/lib/python3.10/site-
> packages/django/db/models/sql/query.py", line 1145, in resolve_expression
> clone.where.resolve_expression(query, *args, **kwargs)
> File "/usr/local/filewave/python/lib/python3.10/site-
> packages/django/db/models/sql/where.py", line 278, in resolve_expression
> clone._resolve_node(clone, *args, **kwargs)
> File "/usr/local/filewave/python/lib/python3.10/site-
> packages/django/db/models/sql/where.py", line 270, in _resolve_node
> cls._resolve_node(child, query, *args, **kwargs)
> File "/usr/local/filewave/python/lib/python3.10/site-
> packages/django/db/models/sql/where.py", line 274, in _resolve_node
> node.rhs = cls._resolve_leaf(node.rhs, query, *args, **kwargs)
> File "/usr/local/filewave/python/lib/python3.10/site-
> packages/django/db/models/sql/where.py", line 263, in _resolve_leaf
> expr = expr.resolve_expression(query, *args, **kwargs)
> File "/usr/local/filewave/python/lib/python3.10/site-
> packages/django/db/models/expressions.py", line 862, in
> resolve_expression
> if col.contains_over_clause:
> AttributeError: 'OuterRef' object has no attribute 'contains_over_clause'
> }}}
>
> Looking at code, the issue seems to be the following:
> {{{
> class ResolvedOuterRef(F):
> """
> An object that contains a reference to an outer query.
>
> In this case, the reference to the outer query has been resolved
> because
> the inner query has been used as a subquery.
> """
>
> contains_aggregate = False
> contains_over_clause = False
>
> def as_sql(self, *args, **kwargs):
> raise ValueError(
> "This queryset contains a reference to an outer query and may
> "
> "only be used in a subquery."
> )
>
> def resolve_expression(self, *args, **kwargs):
> col = super().resolve_expression(*args, **kwargs)
> if col.contains_over_clause:
> raise NotSupportedError(
> f"Referencing outer query window expression is not
> supported: "
> f"{self.name}."
> )
> }}}
>
> In case of OuterRef(OuterRef( "field" )), `col =
> super().resolve_expression(*args, **kwargs)` will use:
> {{{
> class OuterRef(F):
> contains_aggregate = False
>
> def resolve_expression(self, *args, **kwargs):
> if isinstance(self.name, self.__class__):
> return self.name
> return ResolvedOuterRef(self.name)
> }}}
> so self.name is an OuterRef, then it returns it directly, and then ` if
> col.contains_over_clause:` fails because col.contains_over_clause is not
> defined for OuterRef.
>
> Looks like adding col.contains_over_clause=False to class OuterRef solves
> the issue - or checking if object col.contains_over_clause.
New description:
Porting our application from Django 3 to 4, we're seeing exception raised
in complex queries using nested OuterRef
{{{
File "/usr/local/python/lib/python3.10/site-
packages/django/db/models/query.py", line 1436, in filter
return self._filter_or_exclude(False, args, kwargs)
File "/usr/local/python/lib/python3.10/site-
packages/django/db/models/query.py", line 1454, in _filter_or_exclude
clone._filter_or_exclude_inplace(negate, args, kwargs)
File "/usr/local/python/lib/python3.10/site-
packages/django/db/models/query.py", line 1461, in
_filter_or_exclude_inplace
self._query.add_q(Q(*args, **kwargs))
File "/usr/local/python/lib/python3.10/site-
packages/django/db/models/sql/query.py", line 1545, in add_q
clause, _ = self._add_q(q_object, self.used_aliases)
File "/usr/local/python/lib/python3.10/site-
packages/django/db/models/sql/query.py", line 1576, in _add_q
child_clause, needed_inner = self.build_filter(
File "/usr/local/python/lib/python3.10/site-
packages/django/db/models/sql/query.py", line 1435, in build_filter
value = self.resolve_lookup_value(value, can_reuse, allow_joins)
File "/usr/local/python/lib/python3.10/site-
packages/django/db/models/sql/query.py", line 1204, in
resolve_lookup_value
value = value.resolve_expression(
File "/usr/local/python/lib/python3.10/site-
packages/django/db/models/query.py", line 1923, in resolve_expression
query = self.query.resolve_expression(*args, **kwargs)
File "/usr/local/python/lib/python3.10/site-
packages/django/db/models/sql/query.py", line 1145, in resolve_expression
clone.where.resolve_expression(query, *args, **kwargs)
File "/usr/local/python/lib/python3.10/site-
packages/django/db/models/sql/where.py", line 278, in resolve_expression
clone._resolve_node(clone, *args, **kwargs)
File "/usr/local/python/lib/python3.10/site-
packages/django/db/models/sql/where.py", line 270, in _resolve_node
cls._resolve_node(child, query, *args, **kwargs)
File "/usr/local/python/lib/python3.10/site-
packages/django/db/models/sql/where.py", line 274, in _resolve_node
node.rhs = cls._resolve_leaf(node.rhs, query, *args, **kwargs)
File "/usr/local/python/lib/python3.10/site-
packages/django/db/models/sql/where.py", line 263, in _resolve_leaf
expr = expr.resolve_expression(query, *args, **kwargs)
File "/usr/local/python/lib/python3.10/site-
packages/django/db/models/expressions.py", line 862, in resolve_expression
if col.contains_over_clause:
AttributeError: 'OuterRef' object has no attribute 'contains_over_clause'
}}}
Looking at code, the issue seems to be the following:
{{{
class ResolvedOuterRef(F):
"""
An object that contains a reference to an outer query.
In this case, the reference to the outer query has been resolved
because
the inner query has been used as a subquery.
"""
contains_aggregate = False
contains_over_clause = False
def as_sql(self, *args, **kwargs):
raise ValueError(
"This queryset contains a reference to an outer query and may
"
"only be used in a subquery."
)
def resolve_expression(self, *args, **kwargs):
col = super().resolve_expression(*args, **kwargs)
if col.contains_over_clause:
raise NotSupportedError(
f"Referencing outer query window expression is not
supported: "
f"{self.name}."
)
}}}
In case of OuterRef(OuterRef( "field" )), `col =
super().resolve_expression(*args, **kwargs)` will use:
{{{
class OuterRef(F):
contains_aggregate = False
def resolve_expression(self, *args, **kwargs):
if isinstance(self.name, self.__class__):
return self.name
return ResolvedOuterRef(self.name)
}}}
so self.name is an OuterRef, then it returns it directly, and then ` if
col.contains_over_clause:` fails because col.contains_over_clause is not
defined for OuterRef.
Looks like adding col.contains_over_clause=False to class OuterRef solves
the issue - or checking if object col.contains_over_clause.
--
--
Ticket URL: <https://code.djangoproject.com/ticket/34803#comment:1>
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