fix: graceful handling of empty __in= lists on ElasticSearch

Thanks to @boulderdave for the ES version of django-haystack#1311

Closes django-haystack#1335

Author: acdha

docs/changelog.rst

@@ -27,6 +27,15 @@ Changes
   Closes #358
   Closes #1311
 
+Fix
+~~~
+
+- Graceful handling of empty __in= lists on ElasticSearch. [Chris Adams]
+
+  Thanks to @boulderdave for the ES version of #1311
+
+  Closes #1335
+
 Other
 ~~~~~
 
@@ -2162,8 +2171,9 @@ v2.0.0 (2013-05-12)
 - Fixed an ES test that seems like a change in behavior in recent ES
   versions. [Jannis Leidel]
 
-- Merge branch 'sq-run-refactor' of https://github.com/mattdeboard
-  /django-haystack into mattdeboard-sq-run-refactor. [Jannis Leidel]
+- Merge branch 'sq-run-refactor' of
+  https://github.com/mattdeboard/django-haystack into mattdeboard-sq-
+  run-refactor. [Jannis Leidel]
 
 - Refactor Solr & ES SearchQuery subclasses to use the ``build_params``
   from ``BaseSearchQuery`` to build the kwargs to be passed to the

haystack/backends/elasticsearch_backend.py

@@ -815,10 +815,13 @@ def build_query_fragment(self, field, filter_type, value):
             elif filter_type == 'in':
                 in_options = []
 
-                for possible_value in prepared_value:
-                    in_options.append(u'"%s"' % self.backend._from_python(possible_value))
+                if not prepared_value:
+                    query_frag = u'(!*:*)'
+                else:
+                    for possible_value in prepared_value:
+                        in_options.append(u'"%s"' % self.backend._from_python(possible_value))
+                    query_frag = u"(%s)" % " OR ".join(in_options)
 
-                query_frag = u"(%s)" % " OR ".join(in_options)
             elif filter_type == 'range':
                 start = self.backend._from_python(prepared_value[0])
                 end = self.backend._from_python(prepared_value[1])

test_haystack/elasticsearch_tests/test_elasticsearch_backend.py

@@ -839,6 +839,17 @@ def test_auto_query(self):
         self.assertEqual(sqs.query.build_query(), u'("pants\\:rule")')
         self.assertEqual(len(sqs), 0)
 
+    def test_query__in(self):
+        self.assertGreater(len(self.sqs), 0)
+        sqs = self.sqs.filter(django_ct='core.mockmodel', django_id__in=[1, 2])
+        self.assertEqual(len(sqs), 2)
+
+    def test_query__in_empty_list(self):
+        """Confirm that an empty list avoids a Elasticsearch exception"""
+        self.assertGreater(len(self.sqs), 0)
+        sqs = self.sqs.filter(id__in=[])
+        self.assertEqual(len(sqs), 0)
+
     # Regressions
 
     def test_regression_proper_start_offsets(self):

test_haystack/elasticsearch_tests/test_elasticsearch_query.py

@@ -162,6 +162,15 @@ def test_narrow_sq(self):
         self.assertEqual(len(sqs.query.narrow_queries), 1)
         self.assertEqual(sqs.query.narrow_queries.pop(), 'foo:(moof)')
 
+    def test_query__in(self):
+        sqs = SearchQuerySet(using='elasticsearch').filter(id__in=[1, 2, 3])
+        self.assertEqual(sqs.query.build_query(), u'id:("1" OR "2" OR "3")')
+
+    def test_query__in_empty_list(self):
+        """Confirm that an empty list avoids a Elasticsearch exception"""
+        sqs = SearchQuerySet(using='elasticsearch').filter(id__in=[])
+        self.assertEqual(sqs.query.build_query(), u'id:(!*:*)')
+
 
 class ElasticsearchSearchQuerySpatialBeforeReleaseTestCase(TestCase):
     def setUp(self):