Merge pull request rmosolgo#2349 from yask123/fix-array-bug

Fix incorrect hasNextPage value when the last cursor belongs to the last element in the array

Author: rmosolgo

lib/graphql/relay/array_connection.rb

@@ -13,7 +13,7 @@ def has_next_page
           sliced_nodes.count > first
         elsif GraphQL::Relay::ConnectionType.bidirectional_pagination && before
           # The original array is longer than the `before` index
-          index_from_cursor(before) < nodes.length
+          index_from_cursor(before) < nodes.length + 1
         else
           false
         end

spec/integration/rails/graphql/relay/array_connection_spec.rb

@@ -65,35 +65,7 @@ def get_page_info(result, key = "bases")
       assert_equal("NQ", result["data"]["rebels"]["ships"]["pageInfo"]["endCursor"])
     end
 
-    it "provides bidirectional_pagination" do
-      result = star_wars_query(query_string, "first" => 1)
-      last_cursor = get_last_cursor(result)
-
-      # When going forwards, bi-directional pagination
-      # returns `true` even for `hasPreviousPage`
-      result = star_wars_query(query_string, "first" => 1, "after" => last_cursor)
-      assert_equal(true, get_page_info(result, "ships")["hasNextPage"])
-      assert_equal(false, get_page_info(result, "ships")["hasPreviousPage"])
-
-      result = with_bidirectional_pagination {
-        star_wars_query(query_string, "first" => 3, "after" => last_cursor)
-      }
-      assert_equal(true, get_page_info(result, "ships")["hasNextPage"])
-      assert_equal(true, get_page_info(result, "ships")["hasPreviousPage"])
-
-      # When going backwards, bi-directional pagination
-      # returns true for `hasNextPage`
-      last_cursor = get_last_cursor(result)
-      result = star_wars_query(query_string, "last" => 1, "before" => last_cursor)
-      assert_equal(false, get_page_info(result, "ships")["hasNextPage"])
-      assert_equal(true, get_page_info(result, "ships")["hasPreviousPage"])
 
-      result = with_bidirectional_pagination {
-        star_wars_query(query_string, "last" => 2, "before" => last_cursor)
-      }
-      assert_equal(true, get_page_info(result, "ships")["hasNextPage"])
-      assert_equal(true, get_page_info(result, "ships")["hasPreviousPage"])
-    end
 
     it 'slices the result' do
       result = star_wars_query(query_string, "first" => 1)
@@ -286,5 +258,52 @@ def get_page_info(result)
         assert_equal(first_second_and_third_names, get_names(result))
       end
     end
+
+    describe "bidirectional pagination" do
+      it "provides bidirectional_pagination" do
+        result = star_wars_query(query_string, "first" => 1)
+        last_cursor = get_last_cursor(result)
+
+        # When going forwards, bi-directional pagination
+        # returns `true` even for `hasPreviousPage`
+        result = star_wars_query(query_string, "first" => 1, "after" => last_cursor)
+        assert_equal(true, get_page_info(result, "ships")["hasNextPage"])
+        assert_equal(false, get_page_info(result, "ships")["hasPreviousPage"])
+
+        result = with_bidirectional_pagination {
+          star_wars_query(query_string, "first" => 3, "after" => last_cursor)
+        }
+        assert_equal(true, get_page_info(result, "ships")["hasNextPage"])
+        assert_equal(true, get_page_info(result, "ships")["hasPreviousPage"])
+
+        # When going backwards, bi-directional pagination
+        # returns true for `hasNextPage`
+        last_cursor = get_last_cursor(result)
+        result = star_wars_query(query_string, "last" => 1, "before" => last_cursor)
+        assert_equal(false, get_page_info(result, "ships")["hasNextPage"])
+        assert_equal(true, get_page_info(result, "ships")["hasPreviousPage"])
+
+        result = with_bidirectional_pagination {
+          star_wars_query(query_string, "last" => 2, "before" => last_cursor)
+        }
+        assert_equal(true, get_page_info(result, "ships")["hasNextPage"])
+        assert_equal(true, get_page_info(result, "ships")["hasPreviousPage"])
+      end
+
+      it "returns correct page info when the before cursor belongs to the last element in the array" do
+        result = with_bidirectional_pagination{
+          star_wars_query(query_string, "last" => 1)
+        }
+
+        last_cursor = get_last_cursor(result)
+
+        result = with_bidirectional_pagination{
+          star_wars_query(query_string, "before" => last_cursor, "last" => 1)
+        }
+
+        assert_equal(true, get_page_info(result, "ships")["hasNextPage"])
+        assert_equal(true, get_page_info(result, "ships")["hasPreviousPage"])
+      end
+    end
   end
 end