fix(agent-core-v2): let session archive proceed after a failed resume (#3139)

A failed resume is cached by SessionManager and rethrown from
whenResumeSettled, so archiving a session whose workspace is gone
failed with the stale resume error even though cold archive only
rewrites session metadata. Swallow the settle failure: still wait for
an in-flight resume before the live/cold classification, but fall
through to the cold metadata path after a failed one.

.changeset/archive-missing-workspace.md

@@ -0,0 +1,5 @@
+---
+"@moonshot-ai/kimi-code": patch
+---
+
+Fix sessions failing to archive when their workspace folder no longer exists.

packages/agent-core-v2/src/workspace/sessionLifecycle/coldSessionArchive.ts

@@ -72,7 +72,7 @@ export async function setSessionArchived(
 ): Promise<ColdSessionArchiveOutcome> {
   const manager = accessor.get(ISessionManager);
   return manager.withLifecycleSerialization(sessionId, async (unguarded) => {
-    await manager.whenResumeSettled(sessionId);
+    await manager.whenResumeSettled(sessionId).catch(() => undefined);
     const live = getLiveSessionById(accessor, sessionId);
     if (live !== undefined) {
       if (archived) await unguarded.archive();

packages/agent-core-v2/test/workspace/sessionLifecycle/coldSessionArchive.test.ts

@@ -171,20 +171,16 @@ describe('setSessionArchivedBatch', () => {
     expect(persisted['isCustomTitle']).toBe(true);
   });
 
-  it('fails the item when a concurrent resume failed instead of cold-classifying', async () => {
+  it('cold-classifies the item when a concurrent resume failed', async () => {
     const outcomes = await setSessionArchivedBatch(
       coldPathAccessor({
-        storeGet: async () => {
-          throw new Error('unreachable — the settle throws first');
-        },
+        storeGet: async () => ({ id: 's1', createdAt: 1, updatedAt: 2, archived: false }),
         resumeError: new Error('resume boom'),
       }),
       ['s1'],
       true,
     );
-    expect(outcomes).toEqual([
-      { id: 's1', ok: false, reason: 'error', message: 'resume boom' },
-    ]);
+    expect(outcomes).toEqual([{ id: 's1', ok: true }]);
   });
 
   it('reads and migrates the legacy session-meta location before answering not_found', async () => {

packages/kap-server/test/sessions.test.ts

@@ -20,9 +20,11 @@ import {
   IEventService,
   ISessionCronService,
   ISessionManager,
+  IWorkspaceService,
   MAIN_AGENT_ID,
   closeSessionById,
   getLiveSessionById,
+  resumeSessionById,
   sessionDirOf,
   type ServiceIdentifier,
   type ScopeSeed,
@@ -782,6 +784,30 @@ describe('server-v2 /api/v1/sessions', () => {
     expect(got.body.data.archived).toBe(true);
   });
 
+  it('archives a cold session after a failed resume when the workspace root is gone', async () => {
+    const cwd = join(home as string, 'gone-ws');
+    await mkdir(cwd);
+    const created = await postJson<SessionWire>('/api/v1/sessions', { metadata: { cwd } });
+    const id = created.body.data.id;
+    await closeSessionById((server as RunningServer).core.accessor, id);
+    await (server as RunningServer).core.accessor
+      .get(IWorkspaceService)
+      .delete(encodeWorkDirKey(cwd));
+    await rm(cwd, { recursive: true, force: true });
+
+    await expect(
+      resumeSessionById((server as RunningServer).core.accessor, id),
+    ).rejects.toThrow(/does not exist/);
+
+    const archived = await postJson<{ archived: boolean }>(`/api/v1/sessions/${id}:archive`);
+    expect(archived.body.code).toBe(0);
+    expect(archived.body.data).toEqual({ archived: true });
+
+    const got = await getJson<SessionWire>(`/api/v1/sessions/${id}`);
+    expect(got.body.code).toBe(0);
+    expect(got.body.data.archived).toBe(true);
+  });
+
   it('restores an archived session via :restore and returns it to the default list', async () => {
     const cwd = home as string;
     const created = await postJson<SessionWire>('/api/v1/sessions', { metadata: { cwd } });