fix: Improve error message for NonNull GQL types (#1333)

* Add test adding schema with NonNull field

* Improve error message for NonNull GQL types

request/graphql/schema/collection.go

@@ -228,6 +228,9 @@ func astTypeToKind(t ast.Type) (client.FieldKind, error) {
 			return client.FieldKind_FOREIGN_OBJECT, nil
 		}
 
+	case *ast.NonNull:
+		return 0, ErrNonNullNotSupported
+
 	default:
 		return 0, NewErrTypeNotFound(t.String())
 	}

request/graphql/schema/errors.go

@@ -36,6 +36,9 @@ var (
 	ErrRelationMissingTypes      = errors.New("relation is missing its defined types and fields")
 	ErrRelationInvalidType       = errors.New("relation has an invalid type to be finalize")
 	ErrMultipleRelationPrimaries = errors.New("relation can only have a single field set as primary")
+	// NonNull is the literal name of the GQL type, so we have to disable the linter
+	//nolint:revive
+	ErrNonNullNotSupported = errors.New("NonNull fields are not currently supported")
 )
 
 func NewErrDuplicateField(objectName, fieldName string) error {

tests/integration/schema/simple_test.go

@@ -212,3 +212,20 @@ func TestSchemaSimpleCreatesSchemaGivenTypeWithStringField(t *testing.T) {
 
 	testUtils.ExecuteTestCase(t, []string{"users"}, test)
 }
+
+func TestSchemaSimpleErrorsGivenNonNullField(t *testing.T) {
+	test := testUtils.TestCase{
+		Actions: []any{
+			testUtils.SchemaUpdate{
+				Schema: `
+					type Users {
+						email: String!
+					}
+				`,
+				ExpectedError: "NonNull fields are not currently supported",
+			},
+		},
+	}
+
+	testUtils.ExecuteTestCase(t, []string{"users"}, test)
+}