image/tree: Sort image tree by name instead of creation date

Sort images alphabetically by their repository tags rather than by
creation date.

When an image has multiple tags, they are sorted internally and the
first tag is used as the representative for sorting the image in the
list. Untagged images are placed at the end.

Signed-off-by: Paweł Gronowski <pawel.gronowski@docker.com>

cli/command/image/tree.go

@@ -7,6 +7,7 @@ import (
 	"context"
 	"fmt"
 	"os"
+	"slices"
 	"sort"
 	"strings"
 
@@ -90,16 +91,36 @@ func runTree(ctx context.Context, dockerCLI command.Cli, opts treeOptions) error
 
 		details.ContentSize = units.HumanSizeWithPrecision(float64(totalContent), 3)
 
+		// Sort tags for this image
+		sortedTags := make([]string, len(img.RepoTags))
+		copy(sortedTags, img.RepoTags)
+		slices.Sort(sortedTags)
+
 		view.images = append(view.images, topImage{
-			Names:    img.RepoTags,
+			Names:    sortedTags,
 			Details:  details,
 			Children: children,
 			created:  img.Created,
 		})
 	}
 
-	sort.Slice(view.images, func(i, j int) bool {
-		return view.images[i].created > view.images[j].created
+	slices.SortFunc(view.images, func(a, b topImage) int {
+		nameA := ""
+		if len(a.Names) > 0 {
+			nameA = a.Names[0]
+		}
+		nameB := ""
+		if len(b.Names) > 0 {
+			nameB = b.Names[0]
+		}
+		// Empty names sort last
+		if (nameA == "") != (nameB == "") {
+			if nameB == "" {
+				return -1
+			}
+			return 1
+		}
+		return strings.Compare(nameA, nameB)
 	})
 
 	return printImageTree(dockerCLI, view)