claude-code - 💡(How to fix) Fix TypeError: onSessionRestored is undefined when resuming sessions in 2.1.120 [2 comments, 2 participants]

ERROR UKH is not a function. (In 'UKH(K)', 'UKH' is undefined) The error appears immediately on TUI mount. The session UI never becomes interactive. The stack trace shows lines 9248–9250 of the bundle, which happen to contain the template literal source for the sandbox required but unavailable error. That made it initially look like a sandbox issue. It is not — getSandboxUnavailableReason() is in the same useEffect body, but never executes because UKH(K) throws first.

TL;DR

The issue can be fixed by providing a default no-op for onSessionRestored or guarding the call with UKH?.(K) to prevent the crash when UKH is undefined.

Guidance

• Verify that the onSessionRestored property is being destructured from a session-config object and that it's missing in the current version (2.1.120).
• Check the surrounding source code to ensure that UKH is not being redefined or overridden elsewhere in the useEffect body.
• Consider adding a default value for onSessionRestored to prevent the crash, such as onSessionRestored: () => {}.
• Alternatively, guard the call to UKH with UKH?.(K) to ensure it's only called when UKH is defined.

Example

// Provide a default no-op for onSessionRestored
({onBeforeQuery: FKH, onTurnComplete: vvH, onSessionRestored: UKH = () => {}, ...})

// or guard the call with UKH?.(K)
UKH?.(K)

Notes

The issue seems to be specific to version 2.1.120, and pinning to 2.1.119 provides a temporary workaround. However, a proper fix should be implemented to prevent the crash in the current version.

Recommendation

Apply the workaround by providing a default no-op for onSessionRestored or guarding the call with UKH?.(K), as this will prevent the crash and allow the TUI to mount correctly.