siyuan-note/siyuan · error

Invalid rich clipboard asset at index

Error message

Invalid rich clipboard asset at index [%d]

What it means

Each rich clipboard asset must carry a non-negative integer index and a non-empty string path; an optional box must be usable as context. This aggregate check fires when index is null/non-numeric/negative/fractional, or path is missing, non-string, or whitespace-only.

Solutions

1. Ensure index is a non-negative integer (Math.floor / Math.trunc it before sending)
2. Ensure path is a non-empty, non-whitespace string (trim it; it is trimmed server-side anyway)
3. Include every required key (index, path) in each asset object; box is the only optional key

Example fix

// before
{index: 1.5, path: ""}
// after
{index: 1, path: "/assets/foo.png"}

for (const [i, a] of assets.entries()) {
  if (!Number.isInteger(a.index) || a.index < 0) throw new Error(`assets[${i}].index must be a non-negative integer`);
  if (typeof a.path !== 'string' || !a.path.trim()) throw new Error(`assets[${i}].path must be a non-empty string`);
}

const isValidAsset = (a) => a && Number.isInteger(a.index) && a.index >= 0 && typeof a.path === 'string' && a.path.trim() !== '';

When it happens

Trigger: Sending an asset like {"index":-1,"path":"/a.png"} (negative index), {"index":1.5,"path":"/a.png"} (non-integer), {"index":0} (missing path), or {"index":0,"path":" "} (blank path) to /api/clipboard/prepareRichText.

Common situations: Client computes index from a zero-based vs one-based list inconsistently; asset path built from an empty variable; floats leaking from JavaScript arithmetic producing 0.30000000000000004-style indices.

Understand the failure class

Background: "Must be a positive integer", "Invalid value", "Unsupported": the invalid-argument-value error family, when a library rejects the value you pass — this error's family across 35 libraries.

Related errors

• Field [assets] must not be empty
• Field [batch] must not be empty
• Field [groups] must not be empty
• Field [assets. .box] should be of type [String]
• Field [assets. ] should be of type [Object]

AI-assisted analysis of siyuan-note/siyuan@9f775e8a12 (2026-09-19). Data as JSON: /api/errors/f92655f0a15011d6. Report an issue: GitHub.

Appendix: source

Thrown at kernel/apicontract/clipboard_input.go:33

			return request, err
		}
		assets, err := legacyField[[]json.RawMessage](fields, "assets", "Array", true)
		if err != nil {
			return request, err
		}
		if len(assets) == 0 {
			return request, fmt.Errorf("Field [assets] must not be empty")
		}
		request.Assets = make([]RichClipboardAsset, 0, len(assets))
		for i, raw := range assets {
			var asset map[string]json.RawMessage
			if json.Unmarshal(raw, &asset) != nil || asset == nil {
				return request, fmt.Errorf("Field [assets.%d] should be of type [Object]", i)
			}
			var index float64
			var path, box string
			if bytes.Equal(asset["index"], []byte("null")) || json.Unmarshal(asset["index"], &index) != nil || index < 0 || index != float64(int(index)) || json.Unmarshal(asset["path"], &path) != nil || strings.TrimSpace(path) == "" {
				return request, fmt.Errorf("Invalid rich clipboard asset at index [%d]", i)
			}
			if value, exists := asset["box"]; exists {
				if bytes.Equal(value, []byte("null")) || json.Unmarshal(value, &box) != nil {
					return request, fmt.Errorf("Field [assets.%d.box] should be of type [String]", i)
				}
			}
			request.Assets = append(request.Assets, RichClipboardAsset{Index: int(index), Path: strings.TrimSpace(path), Box: strings.TrimSpace(box)})
		}
		return
	}
	CleanupRichText.decodeRequest = func(reader io.Reader) (request CleanupRichTextRequest, err error) {
		fields, err := blockRequestFields(reader, "/api/clipboard/cleanupRichText")
		if err != nil {
			return request, err
		}
		request.Batch, err = legacyField[string](fields, "batch", "String", true)
		if err != nil {
			return request, err

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