fix tag parsing

field/index_tag.go

@@ -3,6 +3,7 @@ package field
 import (
 	"reflect"
 	"regexp"
+	"slices"
 	"strconv"
 	"strings"
 )
@@ -71,13 +72,13 @@ func NewIndexTag(field reflect.StructField) IndexTag {
 	}
 }
 
-type tagOptions string
+type tagOptions []string
 
 // parseTag splits a struct field's index tag into its id and
 // comma-separated options.
 func parseTag(tag string) (string, tagOptions) {
 	tag, opt, _ := strings.Cut(tag, ",")
-	return tag, tagOptions(opt)
+	return tag, tagOptions(strings.Split(opt, ","))
 }
 
 // Contains reports whether a comma-separated list of options
@@ -87,13 +88,6 @@ func (o tagOptions) Contains(optionName string) bool {
 	if len(o) == 0 {
 		return false
 	}
-	s := string(o)
-	for s != "" {
-		var name string
-		name, s, _ = strings.Cut(s, ",")
-		if name == optionName {
-			return true
-		}
-	}
-	return false
+
+	return slices.Contains(o, optionName)
 }