siyuan-note/siyuan · error

Field [groups. ] should be of type [String]

Error message

Field [groups.%d] should be of type [String]

What it means

Request-validation error for the clipboard batch-input API: the element at index %d of the groups array is not a JSON string (null or another type), so the batch groups payload is malformed and the request is rejected before processing.

Solutions

1. Send group identifiers as plain strings, e.g. groups: ["g1", "g2"]
2. Map object arrays to their ID strings before sending (groups.map(g => g.id))
3. Filter out null/undefined entries before serializing the payload

Example fix

// before
{groups: [{id: "g1"}]}
// after
{groups: ["g1"]}

const isStringArray = (g) => Array.isArray(g) && g.every((x) => typeof x === 'string' && x !== null);

const isStringArray = (v) => Array.isArray(v) && v.every((x) => typeof x === 'string');

When it happens

Trigger: Sending {"groups":[null]}, {"groups":[123]}, or {"groups":[{"id":"g1"}]} to /api/clipboard/cleanupRichText instead of an array of plain strings.

Common situations: Group objects serialized instead of their ID strings (missing .map(g => g.id)); null entries introduced by sparse arrays or failed lookups; mixing numeric group indexes with string IDs after a schema change.

Understand the failure class

Background: Type mismatch errors: IllegalArgumentException, TypeError and type guards across 150 open-source libraries — this error's family across 150 libraries.

Related errors

• Field [assets. .box] should be of type [String]
• Field [assets. ] should be of type [Object]
• attr must be a string or null (got %T)
• block [ ] type is locked: expected , got
• createDocTree definition must be a list

AI-assisted analysis of siyuan-note/siyuan@9f775e8a12 (2026-09-19). Data as JSON: /api/errors/09e8927b7c2fd480. Report an issue: GitHub.

Appendix: source

Thrown at kernel/apicontract/clipboard_input.go:68

		if err != nil {
			return request, err
		}
		request.Batch = strings.TrimSpace(request.Batch)
		if request.Batch == "" {
			return request, fmt.Errorf("Field [batch] must not be empty")
		}
		groups, err := legacyField[[]json.RawMessage](fields, "groups", "Array", true)
		if err != nil {
			return request, err
		}
		request.Groups = make([]string, 0, len(groups))
		if len(groups) == 0 {
			return request, fmt.Errorf("Field [groups] must not be empty")
		}
		for i, raw := range groups {
			var group string
			if bytes.Equal(raw, []byte("null")) || json.Unmarshal(raw, &group) != nil {
				return request, fmt.Errorf("Field [groups.%d] should be of type [String]", i)
			}
			request.Groups = append(request.Groups, group)
		}
		return
	}
}

View on GitHub (pinned to 9f775e8a12)