siyuan-note/siyuan · error

Field [ ] is required

Error message

Field [%s] is required

What it means

The checkBlockRef decoder's readArray helper treats a missing key or an explicit JSON null for a required field as an error: 'Field [key] is required'. Required id-array fields must be present and non-null; empty arrays may additionally be rejected when the nonempty flag is set.

Solutions

1. Include the required field as a JSON array in the body, e.g. {"ids":["20240101120000-abcdefg"]}.
2. Replace null with an empty array if an empty set is acceptable, or omit the call when there is nothing to check.
3. Fix client serialization so undefined/None fields are dropped or defaulted, not sent as null.
4. Check the endpoint's current contract — the field may have become required after an update.

Example fix

// before
{"ids": null}
// after
{"ids": ["20240101120000-abcdefg", "20240101120000-hijklmn"]}

const required = ["ids"];
for (const k of required) {
  if (!Array.isArray(payload[k])) { throw new Error(`field ${k} must be present and an array`); }
}

const isPresentArray = (v) => Array.isArray(v);

try {
  await post("/api/block/checkBlockRef", payload);
} catch (e) {
  const m = String(e.message).match(/Field \[(\w+)\] is required/);
  if (m) { payload[m[1]] = payload[m[1]] ?? []; await post("/api/block/checkBlockRef", payload); }
  else { throw e; }
}

When it happens

Trigger: POSTing to /api/block/checkBlockRef without the ids field ({}) , with {"ids":null}, or omitting another required array field the decoder asks for via readArray(key, true, ...).

Common situations: Clients serializing undefined values as null (JSON.stringify drops undefined but libraries often emit null), payloads built conditionally where the field was skipped, or API version drift where a formerly optional field became required.

Understand the failure class

Background: "missing required argument" and "the following required arguments were not provided": what required-argument errors mean and how to fix them — this error's family across 20 libraries.

Related errors

• element [ ]
• empty JSON value
• entry [ ]
• Field [conf] should be of type [Object]
• Field [ ] has an invalid constant

AI-assisted analysis of siyuan-note/siyuan@9f775e8a12 (2026-09-19). Data as JSON: /api/errors/206f7549cb24bb91. Report an issue: GitHub.

Appendix: source

Thrown at kernel/apicontract/block_remaining.go:85

	fields, err := blockRequestFields(reader, "/api/block/checkBlockRef")
	if err != nil {
		return request, err
	}
	if raw, present := fields["scope"]; present {
		if bytes.Equal(raw, []byte("null")) || json.Unmarshal(raw, &request.Scope) != nil {
			return request, errors.New("Field [scope] should be of type [String]")
		}
	}
	if strings.TrimSpace(request.Scope) == "" {
		request.Scope = "blocks"
	}
	readArray := func(key string, required, nonempty bool) ([]string, error) {
		raw, present := fields[key]
		if !present && !required {
			return nil, nil
		}
		if !present || bytes.Equal(raw, []byte("null")) {
			return nil, fmt.Errorf("Field [%s] is required", key)
		}
		var entries []json.RawMessage
		if json.Unmarshal(raw, &entries) != nil {
			return nil, fmt.Errorf("Field [%s] should be of type [Array]", key)
		}
		if nonempty && len(entries) == 0 {
			return nil, fmt.Errorf("Field [%s] must not be empty", key)
		}
		var values []string
		seen := map[string]bool{}
		for _, entry := range entries {
			var value string
			if json.Unmarshal(entry, &value) != nil || strings.TrimSpace(value) == "" {
				return nil, fmt.Errorf("Field [%s] should contain non-empty strings", key)
			}
			if !seen[value] {
				values = append(values, value)
				seen[value] = true

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