do not save if no effective changes for edit, dump

cmd/pttodo-cli/cli.go

@@ -195,6 +195,19 @@ func edit(dry bool, filepaths []string) error {
 	}
 	saveOne := func(filepath string) error {
 		tempFile := path.Join(tempDir, path.Base(filepath))
+		var rootTemp, rootOld pttodo.Root
+		if a, err := ioutil.ReadFile(tempFile); err != nil {
+			return err
+		} else if err := yaml.Unmarshal(a, &rootTemp); err != nil {
+			return err
+		} else if b, err := ioutil.ReadFile(filepath); err != nil {
+			return err
+		} else if err := yaml.Unmarshal(b, &rootOld); err != nil {
+			return err
+		} else if rootTemp.Equals(rootOld) {
+			log.Printf("no changes to %s", filepath)
+			return nil
+		}
 		if dry {
 			log.Printf("would've saved %s as %s", tempFile, filepath)
 			return nil
@@ -295,22 +308,32 @@ func dump(dry bool, writer io.Writer, filepaths []string, tags []string, search,
 			return err
 		}
 
-		var root2 pttodo.Root
+		var root2, root2post pttodo.Root
 		if err := yaml.Unmarshal(b, &root2); err != nil {
 			return err
 		}
+		if err := yaml.Unmarshal(b, &root2post); err != nil {
+			return err
+		}
+
 		root2.MoveScheduledToTodo()
-		root.MergeIn(root2)
 
 		if !dry {
-			b3, err := yaml.Marshal(root2)
-			if err != nil {
-				return err
-			}
-			if err := os.WriteFile(filepath, b3, os.ModePerm); err != nil {
-				return err
+			if !root2.Equals(root2post) {
+				log.Printf("refreshing %s", filepath)
+				b3, err := yaml.Marshal(root2)
+				if err != nil {
+					return err
+				}
+				if err := os.WriteFile(filepath, b3, os.ModePerm); err != nil {
+					return err
+				}
+			} else {
+				log.Printf("not refreshing %s", filepath)
 			}
 		}
+
+		root.MergeIn(root2)
 	}
 
 	root.MoveScheduledToTodo()