siyuan-note/siyuan · error

Field [ ] must not be empty

Error message

Field [%s] must not be empty

What it means

avDecodeParsedRequest walks request struct fields reflectively; for string-kind fields tagged with the ,trim, api option, the decoded value is trimmed and an all-whitespace/empty value fails with 'Field [<name>] must not be empty'. Used by endpoints like getAttributeViewPasteRows and createAttributeViewItem variants.

Solutions

1. Provide a non-empty, trimmed value for the flagged field
2. Validate inputs client-side (trim + length check) before invoking the endpoint
3. If the field should be optional, verify you are calling the right endpoint for your use case

Example fix

// before
fetchPost("/api/av/getAttributeViewPasteRows", {avID: "  ", srcIDs});
// after
const id = avID.trim();
if (!id) throw new Error("avID is required");
fetchPost("/api/av/getAttributeViewPasteRows", {avID: id, srcIDs});

function assertTrimmed(payload, names) { for (const n of names) { const v = payload[n]; if (typeof v !== "string" || !v.trim()) throw new Error(`Field [${n}] must not be empty`); } }

const isTrimmedNonEmpty = (v) => typeof v === "string" && v.trim() !== "";

try { await post(avEndpoint, payload); } catch (e) { if (/must not be empty/.test(e.message)) { /* surface which field: e.message */ } else throw e; }

When it happens

Trigger: Calling /api/av/getAttributeViewPasteRows, getAttributeViewFieldViews, or createAttributeViewItem* with a required,trim string field (e.g. avID, srcIDs values) set to "", " ", or missing while required.

Common situations: Row/column IDs extracted from UI state that came back empty, copy/paste flows where the source selection was empty, API scripts hardcoding blank strings during testing.

Understand the failure class

Background: "must not be empty", "cannot be empty" — required-field validation errors across open-source libraries — this error's family across 41 libraries.

Related errors

• Field [ ] must not be empty
• AI editor action must not be empty
• AI editor input is empty
• asset data is empty
• at least one asset path or mapping is required

AI-assisted analysis of siyuan-note/siyuan@9f775e8a12 (2026-09-19). Data as JSON: /api/errors/f4a2887c7f48583a. Report an issue: GitHub.

Appendix: source

Thrown at kernel/apicontract/av_decode.go:144

func avDecodeParsedRequest[Request any](reader io.Reader, path string) (request Request, err error) {
	fields, err := blockRequestFields(reader, path)
	if err != nil {
		return request, err
	}
	value := reflect.ValueOf(&request).Elem()
	for i := 0; i < value.NumField(); i++ {
		field := value.Type().Field(i)
		name := field.Tag.Get("json")
		options := "," + field.Tag.Get("api") + ","
		required := !strings.Contains(options, ",optional,")
		switch field.Type.Kind() {
		case reflect.String:
			var decoded string
			decoded, err = legacyField[string](fields, name, "String", required)
			if err == nil && strings.Contains(options, ",trim,") {
				decoded = strings.TrimSpace(decoded)
				if decoded == "" {
					err = fmt.Errorf("Field [%s] must not be empty", name)
				}
			}
			value.Field(i).SetString(decoded)
		case reflect.Bool:
			var decoded bool
			decoded, err = legacyField[bool](fields, name, "Boolean", required)
			value.Field(i).SetBool(decoded)
		case reflect.Float64:
			var decoded float64
			decoded, err = legacyField[float64](fields, name, "Number", required)
			value.Field(i).SetFloat(decoded)
		case reflect.Slice:
			var entries []json.RawMessage
			entries, err = legacyField[[]json.RawMessage](fields, name, "Array", required)
			var decoded []string
			for _, entry := range entries {
				var item string
				if !bytes.Equal(entry, []byte("null")) && json.Unmarshal(entry, &item) == nil {

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