fix(management): improve error handling and normalize YAML comment indentation

Enhance error management for file operations and clean up temporary files. Add `NormalizeCommentIndentation` function to ensure YAML comments maintain consistent formatting.

internal/api/handlers/management/config_basic.go

@@ -28,7 +28,7 @@ func (h *Handler) GetConfigYAML(c *gin.Context) {
 		return
 	}
 	var node yaml.Node
-	if err := yaml.Unmarshal(data, &node); err != nil {
+	if err = yaml.Unmarshal(data, &node); err != nil {
 		c.JSON(http.StatusInternalServerError, gin.H{"error": "parse_failed", "message": err.Error()})
 		return
 	}
@@ -41,17 +41,18 @@ func (h *Handler) GetConfigYAML(c *gin.Context) {
 }
 
 func WriteConfig(path string, data []byte) error {
+	data = config.NormalizeCommentIndentation(data)
 	f, err := os.OpenFile(path, os.O_WRONLY|os.O_CREATE|os.O_TRUNC, 0644)
 	if err != nil {
 		return err
 	}
-	if _, err := f.Write(data); err != nil {
-		f.Close()
-		return err
+	if _, errWrite := f.Write(data); errWrite != nil {
+		_ = f.Close()
+		return errWrite
 	}
-	if err := f.Sync(); err != nil {
-		f.Close()
-		return err
+	if errSync := f.Sync(); errSync != nil {
+		_ = f.Close()
+		return errSync
 	}
 	return f.Close()
 }
@@ -63,7 +64,7 @@ func (h *Handler) PutConfigYAML(c *gin.Context) {
 		return
 	}
 	var cfg config.Config
-	if err := yaml.Unmarshal(body, &cfg); err != nil {
+	if err = yaml.Unmarshal(body, &cfg); err != nil {
 		c.JSON(http.StatusBadRequest, gin.H{"error": "invalid_yaml", "message": err.Error()})
 		return
 	}
@@ -75,18 +76,20 @@ func (h *Handler) PutConfigYAML(c *gin.Context) {
 		return
 	}
 	tempFile := tmpFile.Name()
-	if _, err := tmpFile.Write(body); err != nil {
-		tmpFile.Close()
-		os.Remove(tempFile)
-		c.JSON(http.StatusInternalServerError, gin.H{"error": "write_failed", "message": err.Error()})
+	if _, errWrite := tmpFile.Write(body); errWrite != nil {
+		_ = tmpFile.Close()
+		_ = os.Remove(tempFile)
+		c.JSON(http.StatusInternalServerError, gin.H{"error": "write_failed", "message": errWrite.Error()})
 		return
 	}
-	if err := tmpFile.Close(); err != nil {
-		os.Remove(tempFile)
-		c.JSON(http.StatusInternalServerError, gin.H{"error": "write_failed", "message": err.Error()})
+	if errClose := tmpFile.Close(); errClose != nil {
+		_ = os.Remove(tempFile)
+		c.JSON(http.StatusInternalServerError, gin.H{"error": "write_failed", "message": errClose.Error()})
 		return
 	}
-	defer os.Remove(tempFile)
+	defer func() {
+		_ = os.Remove(tempFile)
+	}()
 	_, err = config.LoadConfigOptional(tempFile, false)
 	if err != nil {
 		c.JSON(http.StatusUnprocessableEntity, gin.H{"error": "invalid_config", "message": err.Error()})

internal/config/config.go

@@ -5,6 +5,7 @@
 package config
 
 import (
+	"bytes"
 	"errors"
 	"fmt"
 	"os"
@@ -462,13 +463,19 @@ func SaveConfigPreserveComments(configFile string, cfg *Config) error {
 		return err
 	}
 	defer func() { _ = f.Close() }()
-	enc := yaml.NewEncoder(f)
+	var buf bytes.Buffer
+	enc := yaml.NewEncoder(&buf)
 	enc.SetIndent(2)
 	if err = enc.Encode(&original); err != nil {
 		_ = enc.Close()
 		return err
 	}
-	return enc.Close()
+	if err = enc.Close(); err != nil {
+		return err
+	}
+	data = NormalizeCommentIndentation(buf.Bytes())
+	_, err = f.Write(data)
+	return err
 }
 
 func sanitizeConfigForPersist(cfg *Config) *Config {
@@ -518,13 +525,40 @@ func SaveConfigPreserveCommentsUpdateNestedScalar(configFile string, path []stri
 		return err
 	}
 	defer func() { _ = f.Close() }()
-	enc := yaml.NewEncoder(f)
+	var buf bytes.Buffer
+	enc := yaml.NewEncoder(&buf)
 	enc.SetIndent(2)
 	if err = enc.Encode(&root); err != nil {
 		_ = enc.Close()
 		return err
 	}
-	return enc.Close()
+	if err = enc.Close(); err != nil {
+		return err
+	}
+	data = NormalizeCommentIndentation(buf.Bytes())
+	_, err = f.Write(data)
+	return err
+}
+
+// NormalizeCommentIndentation removes indentation from standalone YAML comment lines to keep them left aligned.
+func NormalizeCommentIndentation(data []byte) []byte {
+	lines := bytes.Split(data, []byte("\n"))
+	changed := false
+	for i, line := range lines {
+		trimmed := bytes.TrimLeft(line, " \t")
+		if len(trimmed) == 0 || trimmed[0] != '#' {
+			continue
+		}
+		if len(trimmed) == len(line) {
+			continue
+		}
+		lines[i] = append([]byte(nil), trimmed...)
+		changed = true
+	}
+	if !changed {
+		return data
+	}
+	return bytes.Join(lines, []byte("\n"))
 }
 
 // getOrCreateMapValue finds the value node for a given key in a mapping node.
@@ -766,6 +800,7 @@ func matchSequenceElement(original []*yaml.Node, used []bool, target *yaml.Node)
 				}
 			}
 		}
+	default:
 	}
 	// Fallback to structural equality to preserve nodes lacking explicit identifiers.
 	for i := range original {