Update frontmatter on title/keywords/signature change

internal/p9/server/server.go

@@ -650,6 +650,9 @@ func (s *server) dispatchWrite(f *fid, tag uint16) *plan9.Fcall {
 		if s.callbacks.OnRename != nil {
 			s.callbacks.OnRename(noteID)
 		}
+		if err := s.updateFrontMatter(note); err != nil {
+			return errorFcall(fc, err.Error())
+		}
 		if err := s.renameNote(note); err != nil {
 			return errorFcall(fc, err.Error())
 		}
@@ -669,6 +672,9 @@ func (s *server) dispatchWrite(f *fid, tag uint16) *plan9.Fcall {
 		if s.callbacks.OnRename != nil {
 			s.callbacks.OnRename(noteID)
 		}
+		if err := s.updateFrontMatter(note); err != nil {
+			return errorFcall(fc, err.Error())
+		}
 		if err := s.renameNote(note); err != nil {
 			return errorFcall(fc, err.Error())
 		}
@@ -680,6 +686,9 @@ func (s *server) dispatchWrite(f *fid, tag uint16) *plan9.Fcall {
 		if s.callbacks.OnRename != nil {
 			s.callbacks.OnRename(noteID)
 		}
+		if err := s.updateFrontMatter(note); err != nil {
+			return errorFcall(fc, err.Error())
+		}
 		if err := s.renameNote(note); err != nil {
 			return errorFcall(fc, err.Error())
 		}
@@ -1008,25 +1017,53 @@ func (s *server) getFileContent(path string) string {
 	case "backlinks":
 		return s.getBacklinks(noteID)
 	case "body":
-		return s.readBody(note.Path)
+		return s.readBody(note)
 	}
 	return ""
 }
 
-// readBody reads the file content at path
+// readBody reads the file content, normalizing frontmatter tags if needed.
-func (s *server) readBody(path string) string {
+// Malformed tags are fixed in place and the file is renamed if necessary.
-	if path == "" {
+func (s *server) readBody(note *metadata.Metadata) string {
+	if note.Path == "" {
 		return ""
 	}
-	data, err := os.ReadFile(path)
+	data, err := os.ReadFile(note.Path)
 	if err != nil {
 		return ""
 	}
+	ext := filepath.Ext(note.Path)
+	fm, fileType, _ := frontmatter.Unmarshal(data, ext)
+	if fm != nil && fm.Title != "" {
+		note.Title = fm.Title
+		note.Tags = fm.Tags
+		note.Signature = fm.Signature
+		normalized := frontmatter.NormalizeTags(data, fm.Tags, fileType)
+		if string(normalized) != string(data) {
+			if err := os.WriteFile(note.Path, normalized, 0644); err == nil {
+				data = normalized
+			}
+		}
+		// Rename if tags changed the filename
+		s.renameNote(note) //nolint:errcheck
+	}
 	return string(data)
 }
 
 // renameNote renames the physical file to match current note metadata and updates note.Path.
 // It is a no-op when the filename is already correct.
+func (s *server) updateFrontMatter(note *metadata.Metadata) error {
+	if note.Path == "" || !disk.SupportsFrontMatter(note.Path) {
+		return nil
+	}
+	_, fileType, err := disk.ExtractFrontMatter(note.Path)
+	if err != nil {
+		return err
+	}
+	fm := metadata.NewFrontMatter(note.Title, note.Signature, note.Tags, note.Identifier)
+	return disk.UpdateFrontMatter(note.Path, fm, fileType)
+}
+
 func (s *server) renameNote(note *metadata.Metadata) error {
 	if note.Path == "" {
 		return nil
@@ -1045,7 +1082,8 @@ func (s *server) renameNote(note *metadata.Metadata) error {
 	return nil
 }
 
-// writeBody writes content to file and syncs frontmatter to metadata
+// writeBody writes content to file and syncs frontmatter to metadata.
+// If frontmatter tags are malformed, they are normalized and written back.
 func (s *server) writeBody(path, body string, note *metadata.Metadata) error {
 	if path == "" {
 		return fmt.Errorf("no path")
@@ -1055,11 +1093,18 @@ func (s *server) writeBody(path, body string, note *metadata.Metadata) error {
 	}
 	// Parse frontmatter and sync to metadata
 	ext := filepath.Ext(path)
-	fm, _, _ := frontmatter.Unmarshal([]byte(body), ext)
+	fm, fileType, _ := frontmatter.Unmarshal([]byte(body), ext)
 	if fm != nil && fm.Title != "" {
 		note.Title = fm.Title
 		note.Tags = fm.Tags
 		note.Signature = fm.Signature
+		// Write normalized tags back into the file
+		normalized := frontmatter.NormalizeTags([]byte(body), fm.Tags, fileType)
+		if string(normalized) != body {
+			if err := os.WriteFile(path, normalized, 0644); err != nil {
+				return err
+			}
+		}
 	}
 	return s.renameNote(note)
 }

pkg/encoding/frontmatter/frontmatter.go

@@ -79,7 +79,13 @@ func Marshal(fm *metadata.FrontMatter, fileType metadata.FileType) []byte {
 	return []byte(content)
 }
 
-var tagSplitRe = regexp.MustCompile(`[\s,;:]+`)
+var (
+	tagSplitRe    = regexp.MustCompile(`[\s,;:]+`)
+	orgFiletagsRe = regexp.MustCompile(`(?m)^(#\+filetags:[ \t]*).*$`)
+	mdYamlTagsRe  = regexp.MustCompile(`(?m)^(tags:[ \t]*).*$`)
+	mdTomlTagsRe  = regexp.MustCompile(`(?m)^(tags[ \t]*=[ \t]*).*$`)
+	txtTagsRe     = regexp.MustCompile(`(?m)^(tags:[ \t]*).*$`)
+)
 var tagStripRe = regexp.MustCompile(`[^a-z0-9]`)
 
 // parseTags parses a raw tag string into normalized tags.
@@ -101,6 +107,33 @@ func parseTags(s string) []string {
 	return tags
 }
 
+// NormalizeTags replaces the tags field in content with the normalized,
+// correctly formatted version for the given file type.
+// Returns the updated content. If no tags field is found, content is unchanged.
+func NormalizeTags(content []byte, tags []string, fileType metadata.FileType) []byte {
+	formatted := formatTags(tags, fileType)
+	text := string(content)
+	switch fileType {
+	case metadata.FileTypeOrg:
+		text = orgFiletagsRe.ReplaceAllString(text, "${1}"+formatted)
+	case metadata.FileTypeMdYaml:
+		// Only replace within the --- block
+		yamlRe := regexp.MustCompile(`(?ms)^---\n(.*?)\n---`)
+		text = yamlRe.ReplaceAllStringFunc(text, func(block string) string {
+			return mdYamlTagsRe.ReplaceAllString(block, "${1}"+formatted)
+		})
+	case metadata.FileTypeMdToml:
+		// Only replace within the +++ block
+		tomlRe := regexp.MustCompile(`(?ms)^\+\+\+\n(.*?)\n\+\+\+`)
+		text = tomlRe.ReplaceAllStringFunc(text, func(block string) string {
+			return mdTomlTagsRe.ReplaceAllString(block, "${1}"+formatted)
+		})
+	case metadata.FileTypeTxt:
+		text = txtTagsRe.ReplaceAllString(text, "${1}"+formatted)
+	}
+	return []byte(text)
+}
+
 // Unmarshal extracts front matter from file content.
 // ext should be the file extension (e.g., ".md", ".org", ".txt").
 // Returns the parsed frontmatter and the detected FileType.