kovidgoyal/kitty · error

terminal asked for drag data from MIME list with out of boun

Error message

terminal asked for drag data from MIME list with out of bounds index: %d

What it means

During a drag operation the terminal requested drag data by index into the offered MIME list, but the index is negative or >= len(offered_mimes). The kitten aborts the drag with finish_drag("EINVAL") and returns this error.

Source

Thrown at kittens/dnd/drag.go:274

			return err
		}
	}
	return dnd.render_screen()
}

func (dnd *dnd) finish_drag(errname string) {
	if errname == "" { // cancel drag
		dnd.lp.QueueDnDData(DC{Type: 'E', Y: -1})
	} else {
		dnd.lp.QueueDnDData(DC{Type: 'E', Payload: []byte(errname)})
	}
	dnd.reset_drag()
}

func (dnd *dnd) handle_data_request(idx int) (err error) {
	if idx < 0 || idx >= len(dnd.drag_status.offered_mimes) {
		dnd.finish_drag("EINVAL")
		return fmt.Errorf("terminal asked for drag data from MIME list with out of bounds index: %d", idx)
	}
	mime := dnd.drag_status.offered_mimes[idx]
	ds := dnd.drag_sources[mime]
	for _, dr := range dnd.drag_status.data_requests {
		if dr.index == idx {
			dnd.finish_drag("EINVAL")
			return fmt.Errorf("terminal sent a duplicate drag data request")
		}
	}
	dr := &data_request{drag_source: ds, index: idx}
	if ds.path == "" {
		dnd.lp.QueueDnDData(DC{Type: 'e', Y: idx, Payload: utils.UnsafeStringToBytes(base64.RawStdEncoding.EncodeToString(ds.data))})
		dnd.lp.QueueDnDData(DC{Type: 'e', Y: idx}) // EOF
		return
	} else {
		if ds.file != nil {
			ds.file.Close()
		}

View on GitHub (pinned to 6d5d0c4406)

Solutions

1. Ensure kitten and kitty terminal come from the same installation/version
2. Update kitty — index desync is a protocol bug fixed in newer releases
3. Reproduce with --debug-input and report upstream if persistent

// Before starting the drag, assert the offered list is non-empty and stable:
if len(dnd.drag_status.offered_mimes) == 0 { return errors.New("no MIMEs offered") }

When it happens

Trigger: handle_data_request(idx) is invoked from on_drag_event with an index outside the range of mimes advertised when the drag started — caused by a protocol bug or a desynchronized MIME list between kitten and terminal.

Common situations: Version mismatch between the kitten and terminal implementations of the DnD protocol; race where the MIME list changed mid-drag; malformed escape sequence decoding the index.

Related errors

• terminal responded with drag source error: %s
• terminal sent a duplicate drag data request
• terminal asked for drag data from URI list but no list prese
• terminal asked for drag data from URI list with out of bound
• This kitten should be run as: kitten quick-access-terminal

AI-assisted analysis of kovidgoyal/kitty@6d5d0c4406 (2026-08-27). Data as JSON: /api/errors/85a0ecac662971db. Report an issue: GitHub.