clientV3: fix behavior of WithPrefix and WithFromKey functions

The use of WithPrefix() and WithFromKey() together is not supported. The
client doesn't respect this behavior currently.

Fixes #10431

clientv3/utils.go

@@ -16,6 +16,9 @@ package clientv3
 
 import (
 	"math/rand"
+	"reflect"
+	"runtime"
+	"strings"
 	"time"
 )
 
@@ -29,3 +32,18 @@ func jitterUp(duration time.Duration, jitter float64) time.Duration {
 	multiplier := jitter * (rand.Float64()*2 - 1)
 	return time.Duration(float64(duration) * (1 + multiplier))
 }
+
+// Check if the provided function is being called in the op options.
+func isOpFuncCalled(op string, opts []OpOption) bool {
+	for _, opt := range opts {
+		v := reflect.ValueOf(opt)
+		if v.Kind() == reflect.Func {
+			if opFunc := runtime.FuncForPC(v.Pointer()); opFunc != nil {
+				if strings.Contains(opFunc.Name(), op) {
+					return true
+				}
+			}
+		}
+	}
+	return false
+}