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Fixed #19964 -- Removed relabel_aliases from some structs 

Before there was need to have both .relabel_aliases() and .clone() for
many structs. Now there is only relabeled_clone() for those structs
where alias is the only mutable attribute.
This commit is contained in:
Anssi Kääriäinen 2013-03-02 01:06:56 +02:00
parent 679af4058d
commit d744c550d5
9 changed files with 79 additions and 105 deletions
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6
django/db/models/fields/__init__.py
View File

@ -344,9 +344,9 @@ class Field(object):
if hasattr(value, 'get_compiler'):
value = value.get_compiler(connection=connection)
if hasattr(value, 'as_sql') or hasattr(value, '_as_sql'):
# If the value has a relabel_aliases method, it will need to
# be invoked before the final SQL is evaluated
if hasattr(value, 'relabel_aliases'):
# If the value has a relabeled_clone method it means the
# value will be handled later on.
if hasattr(value, 'relabeled_clone'):
return value
if hasattr(value, 'as_sql'):
sql, params = value.as_sql()

6
django/db/models/fields/related.py
View File

@ -153,9 +153,9 @@ class RelatedField(object):
if hasattr(value, 'get_compiler'):
value = value.get_compiler(connection=connection)
if hasattr(value, 'as_sql') or hasattr(value, '_as_sql'):
# If the value has a relabel_aliases method, it will need to
# be invoked before the final SQL is evaluated
if hasattr(value, 'relabel_aliases'):
# If the value has a relabeled_clone method it means the
# value will be handled later on.
if hasattr(value, 'relabeled_clone'):
return value
if hasattr(value, 'as_sql'):
sql, params = value.as_sql()

11
django/db/models/sql/aggregates.py
View File

@ -63,14 +63,11 @@ class Aggregate(object):
self.field = tmp
def clone(self):
# Different aggregates have different init methods, so use copy here
# deepcopy is not needed, as self.col is only changing variable.
return copy.copy(self)
def relabel_aliases(self, change_map):
def relabeled_clone(self, change_map):
clone = copy.copy(self)
if isinstance(self.col, (list, tuple)):
self.col = (change_map.get(self.col[0], self.col[0]), self.col[1])
clone.col = (change_map.get(self.col[0], self.col[0]), self.col[1])
return clone
def as_sql(self, qn, connection):
"Return the aggregate, rendered as SQL with parameters."

12
django/db/models/sql/datastructures.py
View File

@ -32,10 +32,8 @@ class Date(object):
self.col = col
self.lookup_type = lookup_type
def relabel_aliases(self, change_map):
c = self.col
if isinstance(c, (list, tuple)):
self.col = (change_map.get(c[0], c[0]), c[1])
def relabeled_clone(self, change_map):
return self.__class__((change_map.get(self.col[0], self.col[0]), self.col[1]))
def as_sql(self, qn, connection):
if isinstance(self.col, (list, tuple)):
@ -53,10 +51,8 @@ class DateTime(object):
self.lookup_type = lookup_type
self.tzname = tzname
def relabel_aliases(self, change_map):
c = self.col
if isinstance(c, (list, tuple)):
self.col = (change_map.get(c[0], c[0]), c[1])
def relabeled_clone(self, change_map):
return self.__class__((change_map.get(self.col[0], self.col[0]), self.col[1]))
def as_sql(self, qn, connection):
if isinstance(self.col, (list, tuple)):

23
django/db/models/sql/expressions.py
View File

@ -1,6 +1,7 @@
from django.core.exceptions import FieldError
from django.db.models.constants import LOOKUP_SEP
from django.db.models.fields import FieldDoesNotExist
import copy
class SQLEvaluator(object):
def __init__(self, expression, query, allow_joins=True, reuse=None):
@ -12,23 +13,23 @@ class SQLEvaluator(object):
self.reuse = reuse
self.expression.prepare(self, query, allow_joins)
def relabeled_clone(self, change_map):
clone = copy.copy(self)
clone.cols = []
for node, col in self.cols[:]:
if hasattr(col, 'relabeled_clone'):
clone.cols.append((node, col.relabeled_clone(change_map)))
else:
clone.cols.append((node,
(change_map.get(col[0], col[0]), col[1])))
return clone
def prepare(self):
return self
def as_sql(self, qn, connection):
return self.expression.evaluate(self, qn, connection)
def relabel_aliases(self, change_map):
new_cols = []
for node, col in self.cols:
if hasattr(col, "relabel_aliases"):
col.relabel_aliases(change_map)
new_cols.append((node, col))
else:
new_cols.append((node,
(change_map.get(col[0], col[0]), col[1])))
self.cols = new_cols
#####################################################
# Vistor methods for initial expression preparation #
#####################################################

31
django/db/models/sql/query.py
View File

@ -294,8 +294,7 @@ class Query(object):
obj.select_for_update_nowait = self.select_for_update_nowait
obj.select_related = self.select_related
obj.related_select_cols = []
obj.aggregates = SortedDict((k, v.clone())
for k, v in self.aggregates.items())
obj.aggregates = self.aggregates.copy()
if self.aggregate_select_mask is None:
obj.aggregate_select_mask = None
else:
@ -559,9 +558,8 @@ class Query(object):
new_col = change_map.get(col[0], col[0]), col[1]
self.select.append(SelectInfo(new_col, field))
else:
item = col.clone()
item.relabel_aliases(change_map)
self.select.append(SelectInfo(item, field))
new_col = col.relabeled_clone(change_map)
self.select.append(SelectInfo(new_col, field))
if connector == OR:
# It would be nice to be able to handle this, but the queries don't
@ -769,26 +767,6 @@ class Query(object):
The principle for promotion is: any alias which is used (it is in
alias_usage_counts), is not used by every child of the ORed filter,
and isn't pre-existing needs to be promoted to LOUTER join.
Some examples (assume all joins used are nullable):
- existing filter: a__f1=foo
- add filter: b__f1=foo|b__f2=foo
In this case we should not promote either of the joins (using INNER
doesn't remove results). We correctly avoid join promotion, because
a is not used in this branch, and b is used two times.
- add filter a__f1=foo|b__f2=foo
In this case we should promote both a and b, otherwise they will
remove results. We will also correctly do that as both aliases are
used, and in addition both are used only once while there are two
filters.
- existing: a__f1=bar
- add filter: a__f2=foo|b__f2=foo
We will not promote a as it is previously used. If the join results
in null, the existing filter can't succeed.
The above (and some more) are tested in queries.DisjunctionPromotionTests
"""
for alias, use_count in alias_usage_counts.items():
if use_count < num_childs and alias not in aliases_before:
@ -807,8 +785,7 @@ class Query(object):
old_alias = col[0]
return (change_map.get(old_alias, old_alias), col[1])
else:
col.relabel_aliases(change_map)
return col
return col.relabeled_clone(change_map)
# 1. Update references in "select" (normal columns plus aliases),
# "group by", "where" and "having".
self.where.relabel_aliases(change_map)

74
django/db/models/sql/where.py
View File

@ -34,9 +34,15 @@ class WhereNode(tree.Node):
The class is tied to the Query class that created it (in order to create
the correct SQL).
The children in this tree are usually either Q-like objects or lists of
[table_alias, field_name, db_type, lookup_type, value_annotation, params].
However, a child could also be any class with as_sql() and relabel_aliases() methods.
A child is usually a tuple of:
(Constraint(alias, targetcol, field), lookup_type, value)
where value can be either raw Python value, or Query, ExpressionNode or
something else knowing how to turn itself into SQL.
However, a child could also be any class with as_sql() and either
relabeled_clone() method or relabel_aliases() and clone() methods. The
second alternative should be used if the alias is not the only mutable
variable.
"""
default = AND
@ -255,30 +261,22 @@ class WhereNode(tree.Node):
lhs = qn(name)
return connection.ops.field_cast_sql(db_type) % lhs
def relabel_aliases(self, change_map, node=None):
def relabel_aliases(self, change_map):
"""
Relabels the alias values of any children. 'change_map' is a dictionary
mapping old (current) alias values to the new values.
"""
if not node:
node = self
for pos, child in enumerate(node.children):
for pos, child in enumerate(self.children):
if hasattr(child, 'relabel_aliases'):
# For example another WhereNode
child.relabel_aliases(change_map)
elif isinstance(child, tree.Node):
self.relabel_aliases(change_map, child)
elif isinstance(child, (list, tuple)):
if isinstance(child[0], (list, tuple)):
elt = list(child[0])
if elt[0] in change_map:
elt[0] = change_map[elt[0]]
node.children[pos] = (tuple(elt),) + child[1:]
else:
child[0].relabel_aliases(change_map)
# Check if the query value also requires relabelling
if hasattr(child[3], 'relabel_aliases'):
child[3].relabel_aliases(change_map)
# tuple starting with Constraint
child = (child[0].relabeled_clone(change_map),) + child[1:]
if hasattr(child[3], 'relabeled_clone'):
child = (child[0], child[1], child[2]) + (
child[3].relabeled_clone(change_map),)
self.children[pos] = child
def clone(self):
"""
@ -290,11 +288,10 @@ class WhereNode(tree.Node):
clone = self.__class__._new_instance(
children=[], connector=self.connector, negated=self.negated)
for child in self.children:
if isinstance(child, tuple):
clone.children.append(
(child[0].clone(), child[1], child[2], child[3]))
else:
if hasattr(child, 'clone'):
clone.children.append(child.clone())
else:
clone.children.append(child)
return clone
class EmptyWhere(WhereNode):
@ -313,11 +310,6 @@ class EverythingNode(object):
def as_sql(self, qn=None, connection=None):
return '', []
def relabel_aliases(self, change_map, node=None):
return
def clone(self):
return self
class NothingNode(object):
"""
@ -326,11 +318,6 @@ class NothingNode(object):
def as_sql(self, qn=None, connection=None):
raise EmptyResultSet
def relabel_aliases(self, change_map, node=None):
return
def clone(self):
return self
class ExtraWhere(object):
def __init__(self, sqls, params):
@ -341,8 +328,6 @@ class ExtraWhere(object):
sqls = ["(%s)" % sql for sql in self.sqls]
return " AND ".join(sqls), list(self.params or ())
def clone(self):
return self
class Constraint(object):
"""
@ -405,12 +390,11 @@ class Constraint(object):
return (self.alias, self.col, db_type), params
def relabel_aliases(self, change_map):
if self.alias in change_map:
self.alias = change_map[self.alias]
def clone(self):
new = Empty()
new.__class__ = self.__class__
new.alias, new.col, new.field = self.alias, self.col, self.field
return new
def relabeled_clone(self, change_map):
if self.alias not in change_map:
return self
else:
new = Empty()
new.__class__ = self.__class__
new.alias, new.col, new.field = change_map[self.alias], self.col, self.field
return new

5
tests/queries/models.py
View File

@ -470,3 +470,8 @@ class Paragraph(models.Model):
class Page(models.Model):
text = models.TextField()
class MyObject(models.Model):
parent = models.ForeignKey('self', null=True, blank=True, related_name='children')
data = models.CharField(max_length=100)
created_at = models.DateTimeField(auto_now_add=True)

16
tests/queries/tests.py
View File

@ -25,7 +25,7 @@ from .models import (Annotation, Article, Author, Celebrity, Child, Cover,
SpecialCategory, OneToOneCategory, NullableName, ProxyCategory,
SingleObject, RelatedObject, ModelA, ModelD, Responsibility, Job,
JobResponsibilities, BaseA, Identifier, Program, Channel, Page, Paragraph,
Chapter, Book)
Chapter, Book, MyObject)
class BaseQuerysetTest(TestCase):
@ -2661,3 +2661,17 @@ class ManyToManyExcludeTest(TestCase):
self.assertNotIn(b1, q)
self.assertIn(b2, q)
self.assertIn(b3, q)
class RelabelCloneTest(TestCase):
def test_ticket_19964(self):
my1 = MyObject.objects.create(data='foo')
my1.parent = my1
my1.save()
my2 = MyObject.objects.create(data='bar', parent=my1)
parents = MyObject.objects.filter(parent=F('id'))
children = MyObject.objects.filter(parent__in=parents).exclude(parent=F('id'))
self.assertEqual(list(parents), [my1])
# Evaluating the children query (which has parents as part of it) does
# not change results for the parents query.
self.assertEqual(list(children), [my2])
self.assertEqual(list(parents), [my1])