Fixed #26608 -- Added support for window expressions (OVER clause).

Thanks Josh Smeaton, Mariusz Felisiak, Sergey Fedoseev, Simon Charettes,
Adam Chainz/Johnson and Tim Graham for comments and reviews and Jamie
Cockburn for initial patch.

3 files changed, 22 insertions, 1 deletions

diff --git a/django/db/models/sql/compiler.py b/django/db/models/sql/compiler.py
index 01c303eb7e..11ff51f60f 100644
--- a/django/db/models/sql/compiler.py
+++ b/django/db/models/sql/compiler.py
@@ -1107,6 +1107,8 @@ class SQLInsertCompiler(SQLCompiler):
                 )
             if value.contains_aggregate:
                 raise FieldError("Aggregate functions are not allowed in this query")
+            if value.contains_over_clause:
+                raise FieldError('Window expressions are not allowed in this query.')
         else:
             value = field.get_db_prep_save(value, connection=self.connection)
         return value
@@ -1262,6 +1264,8 @@ class SQLUpdateCompiler(SQLCompiler):
                 val = val.resolve_expression(self.query, allow_joins=False, for_save=True)
                 if val.contains_aggregate:
                     raise FieldError("Aggregate functions are not allowed in this query")
+                if val.contains_over_clause:
+                    raise FieldError('Window expressions are not allowed in this query.')
             elif hasattr(val, 'prepare_database_save'):
                 if field.remote_field:
                     val = field.get_db_prep_save(
diff --git a/django/db/models/sql/query.py b/django/db/models/sql/query.py
index 017edea873..4cd22c7b8a 100644
--- a/django/db/models/sql/query.py
+++ b/django/db/models/sql/query.py
@@ -13,7 +13,7 @@ from string import ascii_uppercase
 from django.core.exceptions import (
     EmptyResultSet, FieldDoesNotExist, FieldError,
 )
-from django.db import DEFAULT_DB_ALIAS, connections
+from django.db import DEFAULT_DB_ALIAS, NotSupportedError, connections
 from django.db.models.aggregates import Count
 from django.db.models.constants import LOOKUP_SEP
 from django.db.models.expressions import Col, Ref
@@ -1125,6 +1125,13 @@ class Query:
         if not arg:
             raise FieldError("Cannot parse keyword query %r" % arg)
         lookups, parts, reffed_expression = self.solve_lookup_type(arg)
+
+        if not getattr(reffed_expression, 'filterable', True):
+            raise NotSupportedError(
+                reffed_expression.__class__.__name__ + ' is disallowed in '
+                'the filter clause.'
+            )
+
         if not allow_joins and len(parts) > 1:
             raise FieldError("Joined field references are not permitted in this query")
 
diff --git a/django/db/models/sql/where.py b/django/db/models/sql/where.py
index ed24b08bd0..0ca95f7018 100644
--- a/django/db/models/sql/where.py
+++ b/django/db/models/sql/where.py
@@ -167,6 +167,16 @@ class WhereNode(tree.Node):
     def contains_aggregate(self):
         return self._contains_aggregate(self)
 
+    @classmethod
+    def _contains_over_clause(cls, obj):
+        if isinstance(obj, tree.Node):
+            return any(cls._contains_over_clause(c) for c in obj.children)
+        return obj.contains_over_clause
+
+    @cached_property
+    def contains_over_clause(self):
+        return self._contains_over_clause(self)
+
     @property
     def is_summary(self):
         return any(child.is_summary for child in self.children)