Fix response for partial admin queries. (#5317)

Handle `[]map[string]interface{}` separately from `[]interface{}` in `completObject` function. This fixes the bug where admin queries returned full info even when asked for partial information.

graphql/e2e/common/admin.go

@@ -29,6 +29,7 @@ import (
 	"github.com/dgraph-io/dgo/v200"
 	"github.com/dgraph-io/dgo/v200/protos/api"
 	"github.com/dgraph-io/dgraph/protos/pb"
+	"github.com/dgraph-io/dgraph/testutil"
 	"github.com/google/go-cmp/cmp"
 	"github.com/google/go-cmp/cmp/cmpopts"
 	"github.com/stretchr/testify/require"
@@ -429,6 +430,34 @@ func health(t *testing.T) {
 	}
 }
 
+func partialHealth(t *testing.T) {
+	queryParams := &GraphQLParams{
+		Query: `query {
+            health {
+              instance
+              status
+              group
+            }
+        }`,
+	}
+	gqlResponse := queryParams.ExecuteAsPost(t, graphqlAdminTestAdminURL)
+	RequireNoGQLErrors(t, gqlResponse)
+	testutil.CompareJSON(t, `{
+        "health": [
+          {
+            "instance": "zero",
+            "status": "healthy",
+            "group": "0"
+          },
+          {
+            "instance": "alpha",
+            "status": "healthy",
+            "group": "1"
+          }
+        ]
+      }`, string(gqlResponse.Data))
+}
+
 // The GraphQL /admin state result should be the same as /state
 func adminState(t *testing.T) {
 	queryParams := &GraphQLParams{

graphql/e2e/common/common.go

@@ -213,6 +213,7 @@ func RunAll(t *testing.T) {
 	// admin tests
 	t.Run("admin", admin)
 	t.Run("health", health)
+	t.Run("partial health", partialHealth)
 	t.Run("state", adminState)
 	t.Run("propagate client remote ip", clientInfoLogin)
 

graphql/resolve/resolver.go

@@ -1178,6 +1178,14 @@ func completeValue(
 		return completeObject(path, field.SelectionSet(), val)
 	case []interface{}:
 		return completeList(path, field, val)
+	case []map[string]interface{}:
+		// This case is different from the []interface{} case above and is true for admin queries
+		// where we built the val ourselves.
+		listVal := make([]interface{}, 0, len(val))
+		for _, v := range val {
+			listVal = append(listVal, v)
+		}
+		return completeList(path, field, listVal)
 	default:
 		if val == nil {
 			if field.Type().ListType() != nil {