Remove duplicate id ranges returned by getsubu/gid for username/uid

pkg/parent/dynidtools/dynidtools.go

@@ -14,6 +14,18 @@ import (
 	"github.com/sirupsen/logrus"
 )
 
+func withoutDuplicates[T idtools.SubIDRange](sliceList []T) []T {
+	seenKeys := make(map[T]bool)
+	var list []T
+	for _, item := range sliceList {
+		if _, value := seenKeys[item]; !value {
+			seenKeys[item] = true
+			list = append(list, item)
+		}
+	}
+	return list
+}
+
 func GetSubIDRanges(uid int, username string) ([]idtools.SubIDRange, []idtools.SubIDRange, error) {
 	getsubidsExeName := "getsubids"
 	if v := os.Getenv("GETSUBIDS"); v != "" {
@@ -52,8 +64,8 @@ func GetSubIDRanges(uid int, username string) ([]idtools.SubIDRange, []idtools.S
 		}
 	}
 
-	u := append(uByUsername, uByUID...)
-	g := append(gByUsername, gByUID...)
+	u := withoutDuplicates(append(uByUsername, uByUID...))
+	g := withoutDuplicates(append(gByUsername, gByUID...))
 	return u, g, nil
 }