diff --git a/graphene_django/fields.py b/graphene_django/fields.py index 78efceb..f7d9a19 100644 --- a/graphene_django/fields.py +++ b/graphene_django/fields.py @@ -147,14 +147,11 @@ class DjangoConnectionField(ConnectionField): if isinstance(iterable, QuerySet): list_length = iterable.count() - list_slice_length = ( - min(max_limit, list_length) if max_limit is not None else list_length - ) else: list_length = len(iterable) - list_slice_length = ( - min(max_limit, list_length) if max_limit is not None else list_length - ) + list_slice_length = ( + min(max_limit, list_length) if max_limit is not None else list_length + ) # If after is higher than list_length, connection_from_list_slice # would try to do a negative slicing which makes django throw an @@ -162,7 +159,11 @@ class DjangoConnectionField(ConnectionField): after = min(get_offset_with_default(args.get("after"), -1) + 1, list_length) if max_limit is not None and "first" not in args: - args["first"] = max_limit + if "last" in args: + args["first"] = list_length + list_slice_length = list_length + else: + args["first"] = max_limit connection = connection_from_list_slice( iterable[after:], diff --git a/graphene_django/tests/test_query.py b/graphene_django/tests/test_query.py index 6add0b8..a2d8373 100644 --- a/graphene_django/tests/test_query.py +++ b/graphene_django/tests/test_query.py @@ -1213,6 +1213,103 @@ def test_should_have_next_page(graphene_settings): } +class TestBackwardPagination: + def setup_schema(self, graphene_settings, max_limit): + graphene_settings.RELAY_CONNECTION_MAX_LIMIT = max_limit + reporters = [Reporter(**kwargs) for kwargs in REPORTERS] + Reporter.objects.bulk_create(reporters) + + class ReporterType(DjangoObjectType): + class Meta: + model = Reporter + interfaces = (Node,) + + class Query(graphene.ObjectType): + all_reporters = DjangoConnectionField(ReporterType) + + schema = graphene.Schema(query=Query) + return schema + + def do_queries(self, schema): + # Simply last 3 + query_last = """ + query { + allReporters(last: 3) { + edges { + node { + firstName + } + } + } + } + """ + + result = schema.execute(query_last) + assert not result.errors + assert len(result.data["allReporters"]["edges"]) == 3 + assert [ + e["node"]["firstName"] for e in result.data["allReporters"]["edges"] + ] == ["First 3", "First 4", "First 5"] + + # Use a combination of first and last + query_first_and_last = """ + query { + allReporters(first: 4, last: 3) { + edges { + node { + firstName + } + } + } + } + """ + + result = schema.execute(query_first_and_last) + assert not result.errors + assert len(result.data["allReporters"]["edges"]) == 3 + assert [ + e["node"]["firstName"] for e in result.data["allReporters"]["edges"] + ] == ["First 1", "First 2", "First 3"] + + # Use a combination of first and last and after + query_first_last_and_after = """ + query queryAfter($after: String) { + allReporters(first: 4, last: 3, after: $after) { + edges { + node { + firstName + } + } + } + } + """ + + after = base64.b64encode(b"arrayconnection:0").decode() + result = schema.execute( + query_first_last_and_after, variable_values=dict(after=after) + ) + assert not result.errors + assert len(result.data["allReporters"]["edges"]) == 3 + assert [ + e["node"]["firstName"] for e in result.data["allReporters"]["edges"] + ] == ["First 2", "First 3", "First 4"] + + def test_should_query(self, graphene_settings): + """ + Backward pagination should work as expected + """ + schema = self.setup_schema(graphene_settings, max_limit=100) + self.do_queries(schema) + + def test_should_query_with_low_max_limit(self, graphene_settings): + """ + When doing backward pagination (using last) in combination with a max limit higher than the number of objects + we should really retrieve the last ones. + """ + schema = self.setup_schema(graphene_settings, max_limit=4) + self.do_queries(schema) + + def test_should_preserve_prefetch_related(django_assert_num_queries): class ReporterType(DjangoObjectType): class Meta: