kovidgoyal/kitty · error

Failed to parse response data: %#v with error

Error message

Failed to parse response data: %#v with error: %w

What it means

For confirmation prompts (is_confirm), RunSSHAskpass JSON-unmarshals the SHM response into a bool. If the payload is not valid JSON boolean (e.g. "true" with quotes, empty, or garbage), this fatal error with the raw data is returned.

Solutions

1. Match kitty and kitten helper versions
2. Ensure nothing else writes to the askpass-* SHM file
3. Retry; if reproducible, capture the printed %#v payload and report it

if !json.Valid(data) { /* abort */ }
var ok bool
if json.Unmarshal(data, &ok) != nil { /* reject before use */ }

func isBoolJSON(b []byte) bool { var v bool; return json.Unmarshal(b, &v) == nil }

When it happens

Trigger: The parent writes a non-boolean JSON payload for a confirm request, or a truncated/corrupted SHM response.

Common situations: Version mismatch between askpass helper and kitty, or memory corruption from concurrent access to the SHM file.

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

• Failed to create SHM file with error
• Failed to flush SHM file with error
• Failed to read from SHM file with error
• Failed to write to SHM file with error
• invalid --ssh-connection-data

AI-assisted analysis of kovidgoyal/kitty@6d5d0c4406 (2026-08-27). Data as JSON: /api/errors/5722036bc340367c. Report an issue: GitHub.

Appendix: source

Thrown at kittens/ssh/askpass.go:160

		return fatal(fmt.Errorf("Failed to flush SHM file with error: %w", err))
	}
	trigger_ask(data_shm.Name())
	for {
		time.Sleep(50 * time.Millisecond)
		if data_shm.Slice()[0] == 1 {
			break
		}
	}
	data, err = shm.ReadWithSize(data_shm, 1)
	if err != nil {
		return fatal(fmt.Errorf("Failed to read from SHM file with error: %w", err))
	}
	response := ""
	if is_confirm {
		var ok bool
		err = json.Unmarshal(data, &ok)
		if err != nil {
			return fatal(fmt.Errorf("Failed to parse response data: %#v with error: %w", string(data), err))
		}
		response = "no"
		if ok {
			response = "yes"
		}
	} else {
		err = json.Unmarshal(data, &response)
		if err != nil {
			return fatal(fmt.Errorf("Failed to parse response data: %#v with error: %w", string(data), err))
		}
		if is_fingerprint_check {
			response = strings.ToLower(response)
			switch response {
			case "y":
				response = "yes"
			case "n":
				response = "no"
			}

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