chore: upgrade coredns version (#550)

vendor/github.com/expr-lang/expr/checker/nature/utils.go

@@ -0,0 +1,76 @@
+package nature
+
+import (
+	"reflect"
+
+	"github.com/expr-lang/expr/internal/deref"
+)
+
+func fieldName(field reflect.StructField) string {
+	if taggedName := field.Tag.Get("expr"); taggedName != "" {
+		return taggedName
+	}
+	return field.Name
+}
+
+func fetchField(t reflect.Type, name string) (reflect.StructField, bool) {
+	// First check all structs fields.
+	for i := 0; i < t.NumField(); i++ {
+		field := t.Field(i)
+		// Search all fields, even embedded structs.
+		if fieldName(field) == name {
+			return field, true
+		}
+	}
+
+	// Second check fields of embedded structs.
+	for i := 0; i < t.NumField(); i++ {
+		anon := t.Field(i)
+		if anon.Anonymous {
+			anonType := anon.Type
+			if anonType.Kind() == reflect.Pointer {
+				anonType = anonType.Elem()
+			}
+			if field, ok := fetchField(anonType, name); ok {
+				field.Index = append(anon.Index, field.Index...)
+				return field, true
+			}
+		}
+	}
+
+	return reflect.StructField{}, false
+}
+
+func StructFields(t reflect.Type) map[string]Nature {
+	table := make(map[string]Nature)
+
+	t = deref.Type(t)
+	if t == nil {
+		return table
+	}
+
+	switch t.Kind() {
+	case reflect.Struct:
+		for i := 0; i < t.NumField(); i++ {
+			f := t.Field(i)
+
+			if f.Anonymous {
+				for name, typ := range StructFields(f.Type) {
+					if _, ok := table[name]; ok {
+						continue
+					}
+					typ.FieldIndex = append(f.Index, typ.FieldIndex...)
+					table[name] = typ
+				}
+			}
+
+			table[fieldName(f)] = Nature{
+				Type:       f.Type,
+				FieldIndex: f.Index,
+			}
+
+		}
+	}
+
+	return table
+}