[1.8.x] Refs #24485 -- Renamed some expression types

Backport of 88d798d71a from master

django/contrib/gis/db/models/fields.py

@@ -2,7 +2,7 @@ from django.contrib.gis import forms
 from django.contrib.gis.db.models.lookups import gis_lookups
 from django.contrib.gis.db.models.proxy import GeometryProxy
 from django.contrib.gis.geometry.backend import Geometry, GeometryException
-from django.db.models.expressions import ExpressionNode
+from django.db.models.expressions import Expression
 from django.db.models.fields import Field
 from django.utils import six
 from django.utils.translation import ugettext_lazy as _
@@ -188,7 +188,7 @@ class GeometryField(GeoSelectFormatMixin, Field):
         returning to the caller.
         """
         value = super(GeometryField, self).get_prep_value(value)
-        if isinstance(value, ExpressionNode):
+        if isinstance(value, Expression):
             return value
         elif isinstance(value, (tuple, list)):
             geom = value[0]
@@ -282,7 +282,7 @@ class GeometryField(GeoSelectFormatMixin, Field):
                     pass
                 else:
                     params += value[1:]
-            elif isinstance(value, ExpressionNode):
+            elif isinstance(value, Expression):
                 params = []
             else:
                 params = [connection.ops.Adapter(value)]

django/contrib/gis/db/models/lookups.py

@@ -4,7 +4,7 @@ import re
 
 from django.core.exceptions import FieldDoesNotExist
 from django.db.models.constants import LOOKUP_SEP
-from django.db.models.expressions import Col, ExpressionNode
+from django.db.models.expressions import Col, Expression
 from django.db.models.lookups import Lookup
 from django.utils import six
 
@@ -80,7 +80,7 @@ class GISLookup(Lookup):
             if not hasattr(geo_fld, 'srid'):
                 raise ValueError('No geographic field found in expression.')
             self.rhs.srid = geo_fld.srid
-        elif isinstance(self.rhs, ExpressionNode):
+        elif isinstance(self.rhs, Expression):
             raise ValueError('Complex expressions not supported for GeometryField')
         elif isinstance(self.rhs, (list, tuple)):
             geom = self.rhs[0]

django/db/models/__init__.py

@@ -4,7 +4,7 @@ import warnings
 
 from django.core.exceptions import ObjectDoesNotExist, ImproperlyConfigured  # NOQA
 from django.db.models.query import Q, QuerySet, Prefetch  # NOQA
-from django.db.models.expressions import ExpressionNode, F, Value, Func, Case, When  # NOQA
+from django.db.models.expressions import Expression, F, Value, Func, Case, When  # NOQA
 from django.db.models.manager import Manager  # NOQA
 from django.db.models.base import Model  # NOQA
 from django.db.models.aggregates import *  # NOQA

django/db/models/expressions.py

@@ -42,8 +42,8 @@ class Combinable(object):
                 other = Value(other)
 
         if reversed:
-            return Expression(other, connector, self)
-        return Expression(self, connector, other)
+            return CombinedExpression(other, connector, self)
+        return CombinedExpression(self, connector, other)
 
     #############
     # OPERATORS #
@@ -156,8 +156,8 @@ class BaseExpression(object):
         ```
         def override_as_sql(self, compiler, connection):
             # custom logic
-            return super(ExpressionNode, self).as_sql(compiler, connection)
-        setattr(ExpressionNode, 'as_' + connection.vendor, override_as_sql)
+            return super(Expression, self).as_sql(compiler, connection)
+        setattr(Expression, 'as_' + connection.vendor, override_as_sql)
         ```
 
         Arguments:
@@ -193,7 +193,7 @@ class BaseExpression(object):
          * summarize: a terminal aggregate clause
          * for_save: whether this expression about to be used in a save or update
 
-        Returns: an ExpressionNode to be added to the query.
+        Returns: an Expression to be added to the query.
         """
         c = self.copy()
         c.is_summary = summarize
@@ -330,17 +330,17 @@ class BaseExpression(object):
         return self
 
 
-class ExpressionNode(BaseExpression, Combinable):
+class Expression(BaseExpression, Combinable):
     """
     An expression that can be combined with other expressions.
     """
     pass
 
 
-class Expression(ExpressionNode):
+class CombinedExpression(Expression):
 
     def __init__(self, lhs, connector, rhs, output_field=None):
-        super(Expression, self).__init__(output_field=output_field)
+        super(CombinedExpression, self).__init__(output_field=output_field)
         self.connector = connector
         self.lhs = lhs
         self.rhs = rhs
@@ -391,7 +391,7 @@ class Expression(ExpressionNode):
         return c
 
 
-class DurationExpression(Expression):
+class DurationExpression(CombinedExpression):
     def compile(self, side, compiler, connection):
         if not isinstance(side, DurationValue):
             try:
@@ -447,7 +447,7 @@ class F(Combinable):
         return OrderBy(self, descending=True)
 
 
-class Func(ExpressionNode):
+class Func(Expression):
     """
     A SQL function call.
     """
@@ -504,7 +504,7 @@ class Func(ExpressionNode):
         return copy
 
 
-class Value(ExpressionNode):
+class Value(Expression):
     """
     Represents a wrapped value as a node within an expression
     """
@@ -557,7 +557,7 @@ class DurationValue(Value):
         return connection.ops.date_interval_sql(self.value)
 
 
-class RawSQL(ExpressionNode):
+class RawSQL(Expression):
     def __init__(self, sql, params, output_field=None):
         if output_field is None:
             output_field = fields.Field()
@@ -574,7 +574,7 @@ class RawSQL(ExpressionNode):
         return [self]
 
 
-class Random(ExpressionNode):
+class Random(Expression):
     def __init__(self):
         super(Random, self).__init__(output_field=fields.FloatField())
 
@@ -585,7 +585,7 @@ class Random(ExpressionNode):
         return connection.ops.random_function_sql(), []
 
 
-class Col(ExpressionNode):
+class Col(Expression):
     def __init__(self, alias, target, output_field=None):
         if output_field is None:
             output_field = target
@@ -613,7 +613,7 @@ class Col(ExpressionNode):
                 self.target.get_db_converters(connection))
 
 
-class Ref(ExpressionNode):
+class Ref(Expression):
     """
     Reference to column alias of the query. For example, Ref('sum_cost') in
     qs.annotate(sum_cost=Sum('cost')) query.
@@ -646,7 +646,7 @@ class Ref(ExpressionNode):
         return [self]
 
 
-class When(ExpressionNode):
+class When(Expression):
     template = 'WHEN %(condition)s THEN %(result)s'
 
     def __init__(self, condition=None, then=None, **lookups):
@@ -702,7 +702,7 @@ class When(ExpressionNode):
         return cols
 
 
-class Case(ExpressionNode):
+class Case(Expression):
     """
     An SQL searched CASE expression:
 
@@ -769,7 +769,7 @@ class Case(ExpressionNode):
         return sql, sql_params
 
 
-class Date(ExpressionNode):
+class Date(Expression):
     """
     Add a date selection column.
     """
@@ -816,7 +816,7 @@ class Date(ExpressionNode):
         return value
 
 
-class DateTime(ExpressionNode):
+class DateTime(Expression):
     """
     Add a datetime selection column.
     """

docs/ref/models/expressions.txt

@@ -284,9 +284,9 @@ should define the desired ``output_field``. For example, adding an
     arithmetic between different types, it's necessary to surround the
     expression in another expression::
 
-        from django.db.models import DateTimeField, ExpressionNode, F
+        from django.db.models import DateTimeField, Expression, F
 
-        Race.objects.annotate(finish=ExpressionNode(
+        Race.objects.annotate(finish=Expression(
             F('start') + F('duration'), output_field=DateTimeField()))
 
 .. versionchanged:: 1.8
@@ -369,13 +369,13 @@ Expression API
 
 Query expressions implement the :ref:`query expression API <query-expression>`,
 but also expose a number of extra methods and attributes listed below. All
-query expressions must inherit from ``ExpressionNode()`` or a relevant
+query expressions must inherit from ``Expression()`` or a relevant
 subclass.
 
 When a query expression wraps another expression, it is responsible for
 calling the appropriate methods on the wrapped expression.
 
-.. class:: ExpressionNode
+.. class:: Expression
 
     .. attribute:: contains_aggregate
 
@@ -489,9 +489,9 @@ We'll start by defining the template to be used for SQL generation and
 an ``__init__()`` method to set some attributes::
 
   import copy
-  from django.db.models import ExpressionNode
+  from django.db.models import Expression
 
-  class Coalesce(ExpressionNode):
+  class Coalesce(Expression):
       template = 'COALESCE( %(expressions)s )'
 
       def __init__(self, expressions, output_field, **extra):

tests/expressions/tests.py

@@ -854,7 +854,7 @@ class ReprTests(TestCase):
         self.assertEqual(repr(Date('published', 'exact')), "Date(published, exact)")
         self.assertEqual(repr(DateTime('published', 'exact', utc)), "DateTime(published, exact, %s)" % utc)
         self.assertEqual(repr(F('published')), "F(published)")
-        self.assertEqual(repr(F('cost') + F('tax')), "<Expression: F(cost) + F(tax)>")
+        self.assertEqual(repr(F('cost') + F('tax')), "<CombinedExpression: F(cost) + F(tax)>")
         self.assertEqual(repr(Func('published', function='TO_CHAR')), "Func(F(published), function=TO_CHAR)")
         self.assertEqual(repr(OrderBy(Value(1))), 'OrderBy(Value(1), descending=False)')
         self.assertEqual(repr(Random()), "Random()")