chore: upgrade coredns version (#550)

vendor/github.com/expr-lang/expr/conf/env.go

@@ -0,0 +1,68 @@
+package conf
+
+import (
+	"fmt"
+	"reflect"
+
+	. "github.com/expr-lang/expr/checker/nature"
+	"github.com/expr-lang/expr/internal/deref"
+	"github.com/expr-lang/expr/types"
+)
+
+func Env(env any) Nature {
+	if env == nil {
+		return Nature{
+			Type:   reflect.TypeOf(map[string]any{}),
+			Strict: true,
+		}
+	}
+
+	switch env := env.(type) {
+	case types.Map:
+		return env.Nature()
+	}
+
+	v := reflect.ValueOf(env)
+	d := deref.Value(v)
+
+	switch d.Kind() {
+	case reflect.Struct:
+		return Nature{
+			Type:   v.Type(),
+			Strict: true,
+		}
+
+	case reflect.Map:
+		n := Nature{
+			Type:   v.Type(),
+			Fields: make(map[string]Nature, v.Len()),
+			Strict: true,
+		}
+
+		for _, key := range v.MapKeys() {
+			elem := v.MapIndex(key)
+			if !elem.IsValid() || !elem.CanInterface() {
+				panic(fmt.Sprintf("invalid map value: %s", key))
+			}
+
+			face := elem.Interface()
+
+			switch face := face.(type) {
+			case types.Map:
+				n.Fields[key.String()] = face.Nature()
+
+			default:
+				if face == nil {
+					n.Fields[key.String()] = Nature{Nil: true}
+					continue
+				}
+				n.Fields[key.String()] = Nature{Type: reflect.TypeOf(face)}
+			}
+
+		}
+
+		return n
+	}
+
+	panic(fmt.Sprintf("unknown type %T", env))
+}