What causes "no valid file paths to write (invalid UTF-8 or path)" in siyuan-note/siyuan?

Validate every path with utf8.ValidString and filepath.Clean before calling WriteFilePaths, and drop empty strings.

no valid file paths to write (invalid UTF-8 or path)

Error message

no valid file paths to write (invalid UTF-8 or path)

What it means

Returned on macOS when the embedded Objective-C writeFilePathsToPasteboard returns -2, meaning the NSMutableArray of NSURL objects ended up empty. That happens only if every input path produced a nil NSString (invalid UTF-8 bytes) or a nil NSURL (path rejected by fileURLWithPath:). The Go side translates -2 into this message.

Source

Thrown at kernel/util/clipboard_darwin.go:100

		return nil
	}
	// 分配 C 的 char* 数组，便于传入 Objective-C
	cPaths := make([]*C.char, len(paths))
	for i, p := range paths {
		cPaths[i] = C.CString(p)
	}
	defer func() {
		for _, c := range cPaths {
			C.free(unsafe.Pointer(c))
		}
	}()
	// 取首元素地址作为 const char** 传入
	ret := C.writeFilePathsToPasteboard((**C.char)(unsafe.Pointer(&cPaths[0])), C.int(len(paths)))
	switch ret {
	case 0:
		return nil
	case -2:
		return errors.New("no valid file paths to write (invalid UTF-8 or path)")
	default:
		return errors.New("failed to write file paths to pasteboard")
	}
}

View on GitHub (pinned to 251596fc0d)

Solutions

Validate every path with utf8.ValidString and filepath.Clean before calling WriteFilePaths, and drop empty strings.
Confirm the caller (kernel/api/clipboard.go:90) is passing a resolved absolute path from model.GetAssetAbsPathInBox rather than a relative or malformed one.
Check for NUL bytes or other control characters in the path and reject them upstream.

Example fix

// before
util.WriteFilePaths(paths)

// after
var clean []string
for _, p := range paths {
    if p == "" || !utf8.ValidString(p) || strings.ContainsRune(p, 0) {
        continue
    }
    clean = append(clean, filepath.Clean(p))
}
if len(clean) == 0 {
    return errors.New("no valid paths")
}
util.WriteFilePaths(clean)

Defensive patterns

Strategy: validation

Validate before calling

func validClipboardPaths(paths []string) bool {
    for _, p := range paths {
        if p == "" || !utf8.ValidString(p) || strings.ContainsRune(p, 0) {
            return false
        }
    }
    return len(paths) > 0
}

Try / catch

if err := util.WriteFilePaths(paths); err != nil {
    if err.Error() == "no valid file paths to write (invalid UTF-8 or path)" {
        // surface a clear 'invalid path' message to the user
    }
}

Prevention

Resolve asset paths through model.GetAssetAbsPathInBox and utf8.ValidString them before writing.
Reject empty strings and NUL-containing strings at the API boundary.

When it happens

Trigger: Calling WriteFilePaths on macOS with a slice whose strings are all invalid UTF-8, empty, or are not representable as file URLs (e.g. contain embedded NUL bytes or are malformed).

Common situations: Asset paths read from a non-UTF-8 filesystem encoding; a corrupt or empty path string passed from the asset API; a path containing a NUL byte after string processing.

Understand the failure class

Parsing and encoding errors: unexpected token, malformed input — why parsers reject input and how to find the real culprit.

Related errors

AI-assisted analysis of siyuan-note/siyuan@251596fc0d (2026-08-12). Data as JSON: /api/errors/9d88e2de630b4dee. Report an issue: GitHub.