Fix calculation of has_next_page in resolve_connection_from_cache (#622)

Author: SupImDos

Diff for: strawberry_django/relay.py

@@ -188,11 +188,15 @@ def resolve_connection_from_cache(
             for node in result
         ]
         has_previous_page = (
-            nodes[0]._strawberry_row_number > 1  # type: ignore
+            result[0]._strawberry_row_number > 1  # type: ignore
+            if result
+            else False
+        )
+        has_next_page = (
+            result[-1]._strawberry_row_number < result[-1]._strawberry_total_count  # type: ignore
             if result
             else False
         )
-        has_next_page = result._strawberry_row_number < result if result else False
 
         return cls(
             edges=edges,

Diff for: tests/relay/test_nested_pagination.py

@@ -0,0 +1,62 @@
+import pytest
+from strawberry.relay import to_base64
+from strawberry.relay.types import PREFIX
+
+from strawberry_django.optimizer import DjangoOptimizerExtension
+from tests import utils
+from tests.projects.faker import IssueFactory, MilestoneFactory
+
+
+@pytest.mark.django_db(transaction=True)
+def test_nested_pagination(gql_client: utils.GraphQLTestClient):
+    # Nested pagination with the same arguments for the parent and child connections
+    query = """
+      query testNestedConnectionPagination($first: Int, $after: String) {
+        milestoneConn(first: $first, after: $after) {
+          edges {
+            node {
+              id
+              issuesWithFilters(first: $first, after: $after) {
+                edges {
+                  node {
+                    id
+                  }
+                }
+              }
+            }
+          }
+        }
+      }
+    """
+
+    # Create 4 milestones, each with 4 issues
+    nested_data = {
+        milestone: IssueFactory.create_batch(4, milestone=milestone)
+        for milestone in MilestoneFactory.create_batch(4)
+    }
+
+    # Run the nested pagination query
+    # We expect only 2 database queries if the optimizer is enabled, otherwise 3 (N+1)
+    with utils.assert_num_queries(2 if DjangoOptimizerExtension.enabled.get() else 3):
+        result = gql_client.query(query, {"first": 2, "after": to_base64(PREFIX, 0)})
+
+    # We expect the 2nd and 3rd milestones each with their 2nd and 3rd issues
+    assert not result.errors
+    assert result.data == {
+        "milestoneConn": {
+            "edges": [
+                {
+                    "node": {
+                        "id": to_base64("MilestoneType", milestone.id),
+                        "issuesWithFilters": {
+                            "edges": [
+                                {"node": {"id": to_base64("IssueType", issue.id)}}
+                                for issue in issues[1:3]
+                            ]
+                        },
+                    }
+                }
+                for milestone, issues in list(nested_data.items())[1:3]
+            ]
+        }
+    }