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Fix session stuck in Stopping state when interrupt hangs #334

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Fix session stuck in Stopping state when interrupt hangs #334

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d4638cd
Fix session stuck in "Stopping" state when interrupt hangs
claude Apr 11, 2026
4109462
Call close() in forceCleanSession to kill orphaned subprocess
claude Apr 11, 2026
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8 changes: 7 additions & 1 deletion src/hooks/useClaudeState.ts
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Original file line number Diff line number Diff line change
Expand Up @@ -61,7 +61,13 @@ export function useClaudeState(sessionId: string) {
);

const sendMutation = trpc.claude.send.useMutation();
const interruptMutation = trpc.claude.interrupt.useMutation();
const interruptMutation = trpc.claude.interrupt.useMutation({
onError: () => {
// If interrupt fails (e.g. timeout), refetch running state
// so the UI doesn't stay stuck on "Interrupting..."
void refetch();
},
});
const answerMutation = trpc.claude.answerQuestion.useMutation();

const send = useCallback(
Expand Down
5 changes: 5 additions & 0 deletions src/hooks/useSessionState.ts
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Expand Up @@ -41,6 +41,11 @@ export function useSessionState(sessionId: string) {
onSuccess: (data) => {
utils.sessions.get.setData({ sessionId }, { session: data.session });
},
onError: () => {
// If the stop mutation fails (e.g. timeout or server error),
// refetch session state so we don't stay stuck on "Stopping..."
void refetch();
},
});

// The API endpoint is "delete" but it now archives instead of permanently deleting
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56 changes: 54 additions & 2 deletions src/server/services/claude-runner.ts
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Expand Up @@ -603,8 +603,21 @@ export function getPendingInput(
};
}

/**
* Race a promise against a timeout. Resolves with `undefined` if the timeout fires first.
*/
function withTimeout<T>(promise: Promise<T>, ms: number): Promise<T | undefined> {
return Promise.race([
promise,
new Promise<undefined>((resolve) => setTimeout(() => resolve(undefined), ms)),
]);
}
Comment on lines +609 to +614
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@gemini-code-assist gemini-code-assist bot Apr 11, 2026

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high

The current implementation of withTimeout has two issues:

  1. Ambiguity: It resolves to undefined both when the timeout occurs and when the input promise resolves to undefined. Since state.currentQuery.interrupt() returns Promise<void>, it always resolves to undefined on success, making the timeout check at line 631 always true.
  2. Resource Leak: The setTimeout timer is not cleared if the promise resolves before the timeout, which can lead to an accumulation of active timers in a long-running process.

I suggest using a wrapper object to distinguish between success and timeout, and ensuring the timer is cleared.

function withTimeout<T>(promise: Promise<T>, ms: number): Promise<{ ok: true; value: T } | { ok: false }> {
  let timeoutId: ReturnType<typeof setTimeout>;
  const timeoutPromise = new Promise<{ ok: false }>((resolve) => {
    timeoutId = setTimeout(() => resolve({ ok: false }), ms);
  });
  return Promise.race([
    promise.then((value) => ({ ok: true as const, value })),
    timeoutPromise,
  ]).finally(() => clearTimeout(timeoutId));
}


const INTERRUPT_TIMEOUT_MS = 5_000;

/**
* Interrupt a running Claude query.
* Uses a timeout to prevent hanging if the SDK's interrupt() never resolves.
*/
export async function interruptClaude(sessionId: string): Promise<boolean> {
const state = sessions.get(sessionId);
Expand All @@ -614,10 +627,18 @@ export async function interruptClaude(sessionId: string): Promise<boolean> {
}

try {
await state.currentQuery.interrupt();
const result = await withTimeout(state.currentQuery.interrupt(), INTERRUPT_TIMEOUT_MS);
if (result === undefined) {
Comment on lines +630 to +631
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@gemini-code-assist gemini-code-assist bot Apr 11, 2026

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high

Update this check to align with the improved withTimeout implementation that uses a wrapper object to distinguish between a successful interruption and a timeout.

Suggested change
const result = await withTimeout(state.currentQuery.interrupt(), INTERRUPT_TIMEOUT_MS);
if (result === undefined) {
const result = await withTimeout(state.currentQuery.interrupt(), INTERRUPT_TIMEOUT_MS);
if (!result.ok) {

log.warn('interruptClaude: Timed out, force-cleaning state', { sessionId });
forceCleanSession(sessionId);
}
return true;
} catch (err) {
log.warn('interruptClaude: Failed', { sessionId, error: toError(err).message });
log.warn('interruptClaude: Failed, force-cleaning state', {
sessionId,
error: toError(err).message,
});
forceCleanSession(sessionId);
return false;
}
}
Expand Down Expand Up @@ -709,6 +730,37 @@ export async function markLastMessageAsInterrupted(sessionId: string): Promise<v
});
}

/**
* Force-clean a session's in-memory state and kill the subprocess.
* Used as a fallback when interrupt() hangs or fails.
*
* Calls close() on the query to trigger the SDK's subprocess kill
* (SIGTERM immediately, SIGKILL after 5s), then cleans up our state.
*/
function forceCleanSession(sessionId: string): void {
const state = sessions.get(sessionId);
if (!state) return;

// close() is synchronous (fire-and-forget) and kills the subprocess
if (state.currentQuery) {
try {
state.currentQuery.close();
} catch {
// Ignore close errors
}
}

if (state.pendingInput) {
state.pendingInput.reject(new Error('Session force-cleaned'));
state.pendingInput = null;
}

state.isRunning = false;
state.currentQuery = null;
sessions.delete(sessionId);
sseEvents.emitClaudeRunning(sessionId, false);
}

/**
* Stop a session's Claude query and clean up state.
* Called when a session is stopped.
Expand Down
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