slopus/happy · error · TmuxSessionIdentifierError

Invalid session name: "${params.session}"

Error message

Invalid session name: "${params.session}"

What it means

This identifier-validation helper (parse/validate entry around tmux.ts:1031) requires params.session to be non-empty and match /^[a-zA-Z0-9._-]+$/. Otherwise it throws TmuxSessionIdentifierError so downstream tmux commands never receive a malformed target.

Source

Thrown at packages/happy-cli/src/utils/tmux.ts:1031

    } catch (error) {
        return {
            valid: false,
            error: error instanceof Error ? error.message : 'Unknown validation error'
        };
    }
}

/**
 * Build a tmux session identifier with validation
 */
export function buildTmuxSessionIdentifier(params: {
    session: string;
    window?: string;
    pane?: string;
}): { success: boolean; identifier?: string; error?: string } {
    try {
        if (!params.session || !/^[a-zA-Z0-9._-]+$/.test(params.session)) {
            throw new TmuxSessionIdentifierError(`Invalid session name: "${params.session}"`);
        }

        if (params.window && !/^[a-zA-Z0-9._-]+$/.test(params.window)) {
            throw new TmuxSessionIdentifierError(`Invalid window name: "${params.window}"`);
        }

        if (params.pane && !/^[0-9]+$/.test(params.pane)) {
            throw new TmuxSessionIdentifierError(`Invalid pane identifier: "${params.pane}"`);
        }

        const identifier: TmuxSessionIdentifier = params;
        return {
            success: true,
            identifier: formatTmuxSessionIdentifier(identifier)
        };
    } catch (error) {
        return {
            success: false,

View on GitHub (pinned to b824cd0a46)

Solutions

1. Pass only the session name portion; move any window into params.window.
2. Sanitize with name.replace(/[^a-zA-Z0-9._-]/g, '-') before the call.
3. Check that the source variable is actually defined/non-empty before invoking.
4. Pre-validate with /^[a-zA-Z0-9._-]+$/ to fail early with your own message.

Example fix

// before
validateIdentifier({ session: 'dev:0' });
// after
validateIdentifier({ session: 'dev', window: '0' });

function assertValidParams(params) {
  if (!params?.session || !/^[a-zA-Z0-9._-]+$/.test(params.session)) {
    throw new Error(`Invalid session: ${JSON.stringify(params?.session)}`);
  }
}
assertValidParams(params);

function hasValidSession(p) {
  return typeof p === 'object' && p !== null &&
    typeof p.session === 'string' && /^[a-zA-Z0-9._-]+$/.test(p.session);
}

try {
  const res = validateIdentifier(params);
  if (!res.success) return res;
} catch (e) {
  if (e instanceof TmuxSessionIdentifierError) {
    return { success: false, error: e.message };
  }
  throw e;
}

When it happens

Trigger: Calling the validator with params.session empty, undefined, or containing disallowed characters (spaces, ':', '/', etc.), e.g. { session: 'my sess' } or { session: '' }.

Common situations: User-supplied session names passed through unvalidated from CLI args or config; reading a session identifier from an env var that is unset; copying a full 'session:window' target into the session field.

Related errors

• Session identifier must be a non-empty string
• Invalid session identifier: missing session name
• Invalid session name: "${sessionName}"
• Invalid window name: "${params.window}"
• Invalid pane identifier: "${params.pane}"

AI-assisted analysis of slopus/happy@b824cd0a46 (2026-08-31). Data as JSON: /api/errors/4c0a88b114f5852f. Report an issue: GitHub.