Sort OSFeatures on format

Ensure the formatting output is consistent

Signed-off-by: Derek McGowan <derek@mcg.dev>

Author: dmcgowan

platforms.go

@@ -114,6 +114,7 @@ import (
 	"path"
 	"regexp"
 	"runtime"
+	"slices"
 	"strconv"
 	"strings"
 
@@ -327,8 +328,13 @@ func FormatAll(platform specs.Platform) string {
 	}
 
 	osOptions := platform.OSVersion
-	for _, feature := range platform.OSFeatures {
-		osOptions += "+" + feature
+	features := platform.OSFeatures
+	if !slices.IsSorted(features) {
+		features = slices.Clone(features)
+		slices.Sort(features)
+	}
+	if len(features) > 0 {
+		osOptions += "+" + strings.Join(features, "+")
 	}
 	if osOptions != "" {
 		OSAndVersion := fmt.Sprintf("%s(%s)", platform.OS, osOptions)

platforms_test.go

@@ -379,6 +379,18 @@ func TestParseSelector(t *testing.T) {
 			formatted:   path.Join("linux(+gpu+simd)", defaultArch, defaultVariant),
 			useV2Format: true,
 		},
+		{
+			input: "linux(+unsorted+erofs)",
+			expected: specs.Platform{
+				OS:           "linux",
+				OSVersion:    "",
+				OSFeatures:   []string{"unsorted", "erofs"},
+				Architecture: defaultArch,
+				Variant:      defaultVariant,
+			},
+			formatted:   path.Join("linux(+erofs+unsorted)", defaultArch, defaultVariant),
+			useV2Format: true,
+		},
 	} {
 		t.Run(testcase.input, func(t *testing.T) {
 			if testcase.skip {