Fixed generated YAML missing 'default' for empty values (#1765)

## Changes
Fixed generated YAML missing 'default' for empty values

## Tests
Added unit test

bundle/config/generate/job.go

@@ -25,6 +25,20 @@ func ConvertJobToValue(job *jobs.Job) (dyn.Value, error) {
 		value["tasks"] = dyn.NewValue(tasks, []dyn.Location{{Line: jobOrder.Get("tasks")}})
 	}
 
+	// We're processing job.Settings.Parameters separately to retain empty default values.
+	if len(job.Settings.Parameters) > 0 {
+		params := make([]dyn.Value, 0)
+		for _, parameter := range job.Settings.Parameters {
+			p := map[string]dyn.Value{
+				"name":    dyn.NewValue(parameter.Name, []dyn.Location{{Line: 0}}), // We use Line: 0 to ensure that the name goes first.
+				"default": dyn.NewValue(parameter.Default, []dyn.Location{{Line: 1}}),
+			}
+			params = append(params, dyn.NewValue(p, []dyn.Location{}))
+		}
+
+		value["parameters"] = dyn.NewValue(params, []dyn.Location{{Line: jobOrder.Get("parameters")}})
+	}
+
 	return yamlsaver.ConvertToMapValue(job.Settings, jobOrder, []string{"format", "new_cluster", "existing_cluster_id"}, value)
 }
 

cmd/bundle/generate/generate_test.go

@@ -152,6 +152,12 @@ func TestGenerateJobCommand(t *testing.T) {
 					},
 				},
 			},
+			Parameters: []jobs.JobParameterDefinition{
+				{
+					Name:    "empty",
+					Default: "",
+				},
+			},
 		},
 	}, nil)
 
@@ -198,6 +204,9 @@ func TestGenerateJobCommand(t *testing.T) {
         - task_key: notebook_task
           notebook_task:
             notebook_path: %s
+      parameters:
+        - name: empty
+          default: ""
 `, filepath.Join("..", "src", "notebook.py")), string(data))
 
 	data, err = os.ReadFile(filepath.Join(srcDir, "notebook.py"))

libs/dyn/yamlsaver/saver.go

@@ -151,6 +151,8 @@ func isScalarValueInString(v dyn.Value) bool {
 	switch v.MustString() {
 	case "true", "false":
 		return true
+	case "":
+		return true
 	default:
 		_, err := parseNumber(v.MustString())
 		return err == nil