diff --git a/django/db/models/query.py b/django/db/models/query.py index 8e2aa0a141..b686fd6cab 100644 --- a/django/db/models/query.py +++ b/django/db/models/query.py @@ -818,12 +818,25 @@ class QuerySet: return clone def union(self, *other_qs, all=False): + # If the query is an EmptyQuerySet, combine all nonempty querysets. + if isinstance(self, EmptyQuerySet): + qs = [q for q in other_qs if not isinstance(q, EmptyQuerySet)] + return qs[0]._combinator_query('union', *qs[1:], all=all) if qs else self return self._combinator_query('union', *other_qs, all=all) def intersection(self, *other_qs): + # If any query is an EmptyQuerySet, return it. + if isinstance(self, EmptyQuerySet): + return self + for other in other_qs: + if isinstance(other, EmptyQuerySet): + return other return self._combinator_query('intersection', *other_qs) def difference(self, *other_qs): + # If the query is an EmptyQuerySet, return it. + if isinstance(self, EmptyQuerySet): + return self return self._combinator_query('difference', *other_qs) def select_for_update(self, nowait=False, skip_locked=False): diff --git a/django/db/models/sql/compiler.py b/django/db/models/sql/compiler.py index f81861ddba..c2fa0bab29 100644 --- a/django/db/models/sql/compiler.py +++ b/django/db/models/sql/compiler.py @@ -390,7 +390,7 @@ class SQLCompiler: features = self.connection.features compilers = [ query.get_compiler(self.using, self.connection) - for query in self.query.combined_queries + for query in self.query.combined_queries if not query.is_empty() ] if not features.supports_slicing_ordering_in_compound: for query, compiler in zip(self.query.combined_queries, compilers): diff --git a/docs/releases/1.11.3.txt b/docs/releases/1.11.3.txt index e742f3e770..33645d05b3 100644 --- a/docs/releases/1.11.3.txt +++ b/docs/releases/1.11.3.txt @@ -29,3 +29,6 @@ Bugfixes * Fixed crash in admin's inlines when a model has an inherited non-editable primary key (:ticket:`27967`). + +* Fixed ``QuerySet.union()``, ``intersection()``, and ``difference()`` when + combining with an ``EmptyQuerySet`` (:ticket:`28293`). diff --git a/tests/queries/test_qs_combinators.py b/tests/queries/test_qs_combinators.py index 120f9b8a9f..e1ff860bf0 100644 --- a/tests/queries/test_qs_combinators.py +++ b/tests/queries/test_qs_combinators.py @@ -42,6 +42,31 @@ class QuerySetSetOperationTests(TestCase): self.assertEqual(len(list(qs1.union(qs2, all=True))), 20) self.assertEqual(len(list(qs1.union(qs2))), 10) + @skipUnlessDBFeature('supports_select_intersection') + def test_intersection_with_empty_qs(self): + qs1 = Number.objects.all() + qs2 = Number.objects.none() + self.assertEqual(len(qs1.intersection(qs2)), 0) + self.assertEqual(len(qs2.intersection(qs1)), 0) + self.assertEqual(len(qs2.intersection(qs2)), 0) + + @skipUnlessDBFeature('supports_select_difference') + def test_difference_with_empty_qs(self): + qs1 = Number.objects.all() + qs2 = Number.objects.none() + self.assertEqual(len(qs1.difference(qs2)), 10) + self.assertEqual(len(qs2.difference(qs1)), 0) + self.assertEqual(len(qs2.difference(qs2)), 0) + + def test_union_with_empty_qs(self): + qs1 = Number.objects.all() + qs2 = Number.objects.none() + self.assertEqual(len(qs1.union(qs2)), 10) + self.assertEqual(len(qs2.union(qs1)), 10) + self.assertEqual(len(qs2.union(qs1, qs1, qs1)), 10) + self.assertEqual(len(qs2.union(qs1, qs1, all=True)), 20) + self.assertEqual(len(qs2.union(qs2)), 0) + def test_limits(self): qs1 = Number.objects.all() qs2 = Number.objects.all()