siyuan-note/siyuan · error

Maximum length is limited to 512 characters

Error message

Maximum length is limited to 512 characters

What it means

renameDoc0 (kernel/model/file.go:2219) enforces the 512-rune cap on document titles (issue #6299). The input first passes normalizeDocTitle (strips '/', removes invalid characters, trims), then utf8.RuneCountInString(title) must be <= 512 or the call fails with Conf.Language(106). Counting is per Unicode rune, not per byte — a CJK title fails at 513 characters while a byte-count check would have allowed far fewer, and ZWJ emoji sequences count as multiple runes.

Solutions

1. Truncate the title to 512 runes (count runes, not bytes/UTF-16 units) before calling the API
2. Validate in UI input fields with a rune counter so users see the limit before submitting
3. For generated titles, cap the source text earlier (e.g. first 500 runes + ellipsis) to leave room for normalization differences

Example fix

// before
fetchPost('/api/filetree/renameDoc', {notebook, path, title: autoSummary}) // may exceed 512 runes

// after
const title = Array.from(autoSummary).slice(0, 512).join('') // rune-safe truncation
fetchPost('/api/filetree/renameDoc', {notebook, path, title})

// Rune-accurate title clamp before renameDoc
func clampTitle(title string) string {
	r := []rune(normalizeDocTitle(title))
	if 512 < len(r) {
		return string(r[:512])
	}
	return string(r)
}

When it happens

Trigger: POST /api/filetree/renameDoc / renameDocByID with a title longer than 512 runes after normalization; typically programmatic titles (auto-generated summaries, concatenated lists, pasted blobs) rather than hand-typed names.

Common situations: Plugins that derive titles from document content; imports where the first line becomes the title; automated pipelines naming docs from long strings.

Related errors

• 106
• 199
• block operation context
• Cannot create a file starting with .
• Conf.Language(0)

AI-assisted analysis of siyuan-note/siyuan@afa823b6b4 (2026-08-18). Data as JSON: /api/errors/b393cf7d443e642d. Report an issue: GitHub.

Appendix: source

Thrown at kernel/model/file.go:2219

func renameDoc0(boxID, p, title string) (err error) {
	box := Conf.Box(boxID)
	if nil == box {
		err = errors.New(Conf.Language(0))
		return
	}

	FlushTxQueue()
	luteEngine := util.NewLute()
	tree, err := filesys.LoadTree(box.ID, p, luteEngine)
	if err != nil {
		return
	}

	title = normalizeDocTitle(title)
	if 512 < utf8.RuneCountInString(title) {
		// 限制笔记本名和文档名最大长度为 `512` https://github.com/siyuan-note/siyuan/issues/6299
		return errors.New(Conf.Language(106))
	}

	var isEmpty bool
	if "" == title {
		title = Conf.language(16)
		isEmpty = true
	}
	// 先规范化输入得到实际会存储的标题，再与旧标题比较
	titleChanged := tree.Root.IALAttr("title") != title

	var emptyAttrUpdated bool
	if titleChanged {
		tree.HPath = path.Join(path.Dir(tree.HPath), title)
		tree.Root.SetIALAttr("title", title)
	}

	// 按需同步“无标题”标记（仅更新 IAL，不触发子树重命名等）
	isTitleEmpty := tree.Root.IALAttr(NodeAttrTitleEmpty) == "true"

View on GitHub (pinned to afa823b6b4)