unapplied-changes: display "no changes" instead of empty response

The string "no changes" is displayed when the current deployment is not
stashed, or when the stashed deployment has the same definition as the
previous non-stashed deployment.

CHANGES.md

@@ -1,6 +1,6 @@
 ## v5.3.0 (unreleased)
 
-* …
+* `koyeb service unapplied-changes <service_id>`: display "no changes" when there is no stashed deployment, or when the stashed deployment is the same as the current deployment.
 
 ## v5.2.0 (2024-10-24)
 

pkg/koyeb/services_show_unapplied_changes.go

@@ -62,8 +62,8 @@ func (h *ServiceHandler) ShowUnappliedChanges(ctx *CLIContext, cmd *cobra.Comman
 
 			// Last deployment is not stashed, render an empty diff
 			if res.Deployments[0].GetStatus() != koyeb.DEPLOYMENTSTATUS_STASHED {
-				// xx := NewShowDeploymentsDiff(jsondiff.Patch{})
-				// ctx.Renderer.Render(xx)
+				showUnappliedChangesReply := NewShowDeploymentsDiff(nil, nil)
+				ctx.Renderer.Render(showUnappliedChangesReply)
 				return nil
 			}
 			stashedDeployment = &res.Deployments[0]
@@ -116,6 +116,10 @@ func (ShowDeploymentsDiff) Title() string {
 }
 
 func (r *ShowDeploymentsDiff) MarshalBinary() ([]byte, error) {
+	if r.diff == nil {
+		return nil, nil
+	}
+
 	formatter := formatter.NewDeltaFormatter()
 	diffString, _ := formatter.Format(r.diff)
 	return []byte(diffString), nil
@@ -126,16 +130,22 @@ func (r *ShowDeploymentsDiff) Headers() []string {
 }
 
 func (r *ShowDeploymentsDiff) Fields() []map[string]string {
-	config := formatter.AsciiFormatterConfig{
-		ShowArrayIndex: true,
-		Coloring:       true,
-	}
+	var diffString string
+
+	if r.diff == nil || len(r.diff.Deltas()) == 0 {
+		diffString = "No unapplied changes"
+	} else {
+		config := formatter.AsciiFormatterConfig{
+			ShowArrayIndex: true,
+			Coloring:       true,
+		}
 
-	var aJson map[string]interface{}
-	_ = json.Unmarshal(r.lhs, &aJson)
+		var aJson map[string]interface{}
+		_ = json.Unmarshal(r.lhs, &aJson)
 
-	formatter := formatter.NewAsciiFormatter(aJson, config)
-	diffString, _ := formatter.Format(r.diff)
+		formatter := formatter.NewAsciiFormatter(aJson, config)
+		diffString, _ = formatter.Format(r.diff)
+	}
 
 	fields := map[string]string{
 		"diff": diffString,