chore: upgrade coredns version (#550)

vendor/github.com/expr-lang/expr/optimizer/const_expr.go

@@ -0,0 +1,81 @@
+package optimizer
+
+import (
+	"fmt"
+	"reflect"
+	"strings"
+
+	. "github.com/expr-lang/expr/ast"
+	"github.com/expr-lang/expr/file"
+)
+
+var errorType = reflect.TypeOf((*error)(nil)).Elem()
+
+type constExpr struct {
+	applied bool
+	err     error
+	fns     map[string]reflect.Value
+}
+
+func (c *constExpr) Visit(node *Node) {
+	defer func() {
+		if r := recover(); r != nil {
+			msg := fmt.Sprintf("%v", r)
+			// Make message more actual, it's a runtime error, but at compile step.
+			msg = strings.Replace(msg, "runtime error:", "compile error:", 1)
+			c.err = &file.Error{
+				Location: (*node).Location(),
+				Message:  msg,
+			}
+		}
+	}()
+
+	if call, ok := (*node).(*CallNode); ok {
+		if name, ok := call.Callee.(*IdentifierNode); ok {
+			fn, ok := c.fns[name.Value]
+			if ok {
+				in := make([]reflect.Value, len(call.Arguments))
+				for i := 0; i < len(call.Arguments); i++ {
+					arg := call.Arguments[i]
+					var param any
+
+					switch a := arg.(type) {
+					case *NilNode:
+						param = nil
+					case *IntegerNode:
+						param = a.Value
+					case *FloatNode:
+						param = a.Value
+					case *BoolNode:
+						param = a.Value
+					case *StringNode:
+						param = a.Value
+					case *ConstantNode:
+						param = a.Value
+
+					default:
+						return // Const expr optimization not applicable.
+					}
+
+					if param == nil && reflect.TypeOf(param) == nil {
+						// In case of nil value and nil type use this hack,
+						// otherwise reflect.Call will panic on zero value.
+						in[i] = reflect.ValueOf(&param).Elem()
+					} else {
+						in[i] = reflect.ValueOf(param)
+					}
+				}
+
+				out := fn.Call(in)
+				value := out[0].Interface()
+				if len(out) == 2 && out[1].Type() == errorType && !out[1].IsNil() {
+					c.err = out[1].Interface().(error)
+					return
+				}
+				constNode := &ConstantNode{Value: value}
+				patchWithType(node, constNode)
+				c.applied = true
+			}
+		}
+	}
+}