fix: empty list is not an empty value for list filters even when a custom filtering method is provided

Author: Thomas Leonard

graphene_django/filter/filters/list_filter.py

@@ -1,12 +1,32 @@
+from django_filters.filters import FilterMethod
+
 from .typed_filter import TypedFilter
 
 
+class ListFilterMethod(FilterMethod):
+    def __call__(self, qs, value):
+        if value is None:
+            return qs
+        return self.method(qs, self.f.field_name, value)
+
+
 class ListFilter(TypedFilter):
     """
     Filter that takes a list of value as input.
     It is for example used for `__in` filters.
     """
 
+    @TypedFilter.method.setter
+    def method(self, value):
+        """
+        Override method setter so that in case a custom `method` is provided, it doesn't fall back to
+        checking if the value is in `EMPTY_VALUES` (from the `__call__` method of the `FilterMethod` class)
+        and instead use our CustomFilterMethod that consider empty lists as values
+        """
+        TypedFilter.method.fset(self, value)
+        if value is not None:
+            self.filter = ListFilterMethod(self)
+
     def filter(self, qs, value):
         """
         Override the default filter class to check first whether the list is

graphene_django/filter/tests/test_typed_filter.py

@@ -1,4 +1,8 @@
+import operator
+from functools import reduce
+
 import pytest
+from django.db.models import Q
 from django_filters import FilterSet
 
 import graphene
@@ -44,6 +48,10 @@ class Meta:
         only_first = TypedFilter(
             input_type=graphene.Boolean, method="only_first_filter"
         )
+        headline_search = ListFilter(
+            method="headline_search_filter",
+            input_type=graphene.List(graphene.String),
+        )
 
         def first_n_filter(self, queryset, _name, value):
             return queryset[:value]
@@ -54,6 +62,13 @@ def only_first_filter(self, queryset, _name, value):
             else:
                 return queryset
 
+        def headline_search_filter(self, queryset, _name, value):
+            if not value:
+                return queryset.none()
+            return queryset.filter(
+                reduce(operator.or_, [Q(headline__icontains=v) for v in value])
+            )
+
     class ArticleType(DjangoObjectType):
         class Meta:
             model = Article
@@ -87,6 +102,7 @@ def test_typed_filter_schema(schema):
         "lang_InStr": "[String]",
         "firstN": "Int",
         "onlyFirst": "Boolean",
+        "headlineSearch": "[String]",
     }
 
     all_articles_filters = (
@@ -104,13 +120,48 @@ def test_typed_filters_work(schema):
     Article.objects.create(headline="A", reporter=reporter, editor=reporter, lang="es")
     Article.objects.create(headline="B", reporter=reporter, editor=reporter, lang="es")
     Article.objects.create(headline="C", reporter=reporter, editor=reporter, lang="en")
+    Article.objects.create(headline="AB", reporter=reporter, editor=reporter, lang="es")
+
+    query = 'query { articles (lang_Contains: "n") { edges { node { headline } } } }'
+
+    result = schema.execute(query)
+    assert not result.errors
+    assert result.data["articles"]["edges"] == [
+        {"node": {"headline": "C"}},
+    ]
+
+    query = "query { articles (firstN: 2) { edges { node { headline } } } }"
+
+    result = schema.execute(query)
+    assert not result.errors
+    assert result.data["articles"]["edges"] == [
+        {"node": {"headline": "A"}},
+        {"node": {"headline": "AB"}},
+    ]
+
+    query = "query { articles (onlyFirst: true) { edges { node { headline } } } }"
+
+    result = schema.execute(query)
+    assert not result.errors
+    assert result.data["articles"]["edges"] == [
+        {"node": {"headline": "A"}},
+    ]
+
+
+def test_list_filters_work(schema):
+    reporter = Reporter.objects.create(first_name="John", last_name="Doe", email="")
+    Article.objects.create(headline="A", reporter=reporter, editor=reporter, lang="es")
+    Article.objects.create(headline="B", reporter=reporter, editor=reporter, lang="es")
+    Article.objects.create(headline="C", reporter=reporter, editor=reporter, lang="en")
+    Article.objects.create(headline="AB", reporter=reporter, editor=reporter, lang="es")
 
     query = "query { articles (lang_In: [ES]) { edges { node { headline } } } }"
 
     result = schema.execute(query)
     assert not result.errors
     assert result.data["articles"]["edges"] == [
         {"node": {"headline": "A"}},
+        {"node": {"headline": "AB"}},
         {"node": {"headline": "B"}},
     ]
 
@@ -120,30 +171,61 @@ def test_typed_filters_work(schema):
     assert not result.errors
     assert result.data["articles"]["edges"] == [
         {"node": {"headline": "A"}},
+        {"node": {"headline": "AB"}},
         {"node": {"headline": "B"}},
     ]
 
-    query = 'query { articles (lang_Contains: "n") { edges { node { headline } } } }'
+    query = "query { articles (lang_InStr: []) { edges { node { headline } } } }"
+
+    result = schema.execute(query)
+    assert not result.errors
+    assert result.data["articles"]["edges"] == []
+
+    query = "query { articles (lang_InStr: null) { edges { node { headline } } } }"
 
     result = schema.execute(query)
     assert not result.errors
     assert result.data["articles"]["edges"] == [
+        {"node": {"headline": "A"}},
+        {"node": {"headline": "AB"}},
+        {"node": {"headline": "B"}},
         {"node": {"headline": "C"}},
     ]
 
-    query = "query { articles (firstN: 2) { edges { node { headline } } } }"
+    query = 'query { articles (headlineSearch: ["a", "B"]) { edges { node { headline } } } }'
 
     result = schema.execute(query)
     assert not result.errors
     assert result.data["articles"]["edges"] == [
         {"node": {"headline": "A"}},
+        {"node": {"headline": "AB"}},
         {"node": {"headline": "B"}},
     ]
 
-    query = "query { articles (onlyFirst: true) { edges { node { headline } } } }"
+    query = "query { articles (headlineSearch: []) { edges { node { headline } } } }"
+
+    result = schema.execute(query)
+    assert not result.errors
+    assert result.data["articles"]["edges"] == []
+
+    query = "query { articles (headlineSearch: null) { edges { node { headline } } } }"
+
+    result = schema.execute(query)
+    assert not result.errors
+    assert result.data["articles"]["edges"] == [
+        {"node": {"headline": "A"}},
+        {"node": {"headline": "AB"}},
+        {"node": {"headline": "B"}},
+        {"node": {"headline": "C"}},
+    ]
+
+    query = 'query { articles (headlineSearch: [""]) { edges { node { headline } } } }'
 
     result = schema.execute(query)
     assert not result.errors
     assert result.data["articles"]["edges"] == [
         {"node": {"headline": "A"}},
+        {"node": {"headline": "AB"}},
+        {"node": {"headline": "B"}},
+        {"node": {"headline": "C"}},
     ]