From c72f7f9400bc30e80c8a95bdbc35e6d99609d519 Mon Sep 17 00:00:00 2001
From: Neil <neil@stably.ai>
Date: Thu, 10 Sep 2026 03:16:29 -0700
Subject: [PATCH] test(repro): #19735 resumes a published mirrored pane before
 its handle lands

---
 .../lib/host-mirror-handle-gap-resume.test.ts | 132 ++++++++++++++++++
 1 file changed, 132 insertions(+)
 create mode 100644 src/renderer/src/lib/host-mirror-handle-gap-resume.test.ts

diff --git a/src/renderer/src/lib/host-mirror-handle-gap-resume.test.ts b/src/renderer/src/lib/host-mirror-handle-gap-resume.test.ts
new file mode 100644
index 00000000000..a1d7b5e1b9a
--- /dev/null
+++ b/src/renderer/src/lib/host-mirror-handle-gap-resume.test.ts
@@ -0,0 +1,132 @@
+import path from 'node:path'
+import { afterEach, beforeEach, describe, expect, it } from 'vitest'
+import { useAppStore, type AppState } from '@/store'
+import { resumeSleepingAgentSessionsForWorktree } from './resume-sleeping-agent-session'
+import { makeCreatedAgentWorktree } from '@/lib/worktree-activation-created-agent-test-state'
+import { makePaneKey } from '../../../shared/stable-pane-id'
+import {
+  markHostSessionMirrorHydrated,
+  resetHostSessionMirrorHydrationForTests
+} from '@/runtime/host-session-mirror-hydration'
+import { clearRuntimeEnvironmentConnectionGenerationsForTests } from '@/store/slices/runtime-status'
+
+// The window this pins: a paired runtime publishes a workspace's tab rows and its PTY handles on
+// separate frames, so there is a frame where the row exists and `ptyIdsByTabId` is still empty.
+// An empty handle map for a row the host is still publishing is `unverifiable`, never `exited`
+// (docs/reference/ssh-execution-boundary.md), so nothing may be resumed off it.
+
+const initialAppStoreState = useAppStore.getState()
+
+const LEAF_ID = '22222222-2222-4222-8222-222222222222'
+const WEB_TAB_ID = 'web-terminal-host-tab-1'
+const RUNTIME_ENV_ID = 'env-handle-gap'
+
+function makeRuntimeOwnedWorktree(): ReturnType<typeof makeCreatedAgentWorktree> {
+  return {
+    ...makeCreatedAgentWorktree(),
+    createdWithAgent: undefined,
+    hostId: `runtime:${encodeURIComponent(RUNTIME_ENV_ID)}`
+  }
+}
+
+/** A published mirrored row: tab, layout leaf, and the leaf's host PTY binding. */
+function seedMirroredWorkspace(worktree: ReturnType<typeof makeCreatedAgentWorktree>): void {
+  const state: Partial<AppState> = {
+    repos: [
+      {
+        id: 'repo-1',
+        path: path.join(path.sep, 'workspace', 'repo'),
+        displayName: 'repo',
+        badgeColor: '#000000',
+        addedAt: 0
+      }
+    ],
+    worktreesByRepo: { 'repo-1': [worktree] },
+    activeRepoId: 'repo-1',
+    activeWorktreeId: worktree.id,
+    activeView: 'terminal',
+    tabsByWorktree: {
+      [worktree.id]: [{ id: WEB_TAB_ID, title: 'Claude', ptyId: null } as never]
+    },
+    terminalLayoutsByTabId: {
+      [WEB_TAB_ID]: {
+        root: { type: 'leaf', leafId: LEAF_ID },
+        activeLeafId: LEAF_ID,
+        expandedLeafId: null,
+        ptyIdsByLeafId: { [LEAF_ID]: 'remote:env-handle-gap@@term_1' }
+      } as never
+    },
+    // The gap itself: the row is published, its handle has not arrived.
+    ptyIdsByTabId: {},
+    sleepingAgentSessionsByPaneKey: {},
+    pendingStartupByTabId: {},
+    automaticAgentResumeClaimsByTabId: {},
+    agentStatusByPaneKey: {}
+  }
+  useAppStore.setState(state as AppState)
+}
+
+/** The capture the reported flow produces: recorded mid-turn, so it is active work, not history. */
+function seedActiveSleepingRecord(worktreeId: string): string {
+  const paneKey = makePaneKey(WEB_TAB_ID, LEAF_ID)
+  useAppStore.setState({
+    sleepingAgentSessionsByPaneKey: {
+      [paneKey]: {
+        paneKey,
+        tabId: WEB_TAB_ID,
+        worktreeId,
+        agent: 'claude',
+        providerSession: { key: 'session_id', id: 'handle-gap-session' },
+        connectionId: null,
+        prompt: '',
+        state: 'working',
+        capturedAt: 1000,
+        updatedAt: 1000,
+        terminalTitle: 'Claude',
+        origin: 'live'
+      }
+    }
+  } as never)
+  return paneKey
+}
+
+describe('resume across the mirror handle gap', () => {
+  beforeEach(() => {
+    useAppStore.setState(initialAppStoreState, true)
+    resetHostSessionMirrorHydrationForTests()
+    clearRuntimeEnvironmentConnectionGenerationsForTests()
+  })
+
+  afterEach(() => {
+    useAppStore.setState(initialAppStoreState, true)
+    resetHostSessionMirrorHydrationForTests()
+    clearRuntimeEnvironmentConnectionGenerationsForTests()
+  })
+
+  it('does not resume a published mirrored pane whose handle has not landed yet', () => {
+    const worktree = makeRuntimeOwnedWorktree()
+    seedMirroredWorkspace(worktree)
+    const paneKey = seedActiveSleepingRecord(worktree.id)
+    // The rows have arrived; only the handles are outstanding.
+    markHostSessionMirrorHydrated(RUNTIME_ENV_ID)
+
+    const launched = resumeSleepingAgentSessionsForWorktree(worktree.id)
+
+    const after = useAppStore.getState()
+    expect(launched).toBe(0)
+    expect(after.tabsByWorktree[worktree.id]).toHaveLength(1)
+    expect(Object.keys(after.pendingStartupByTabId)).toHaveLength(0)
+    // The record survives: the next frame carries the handle and decides for real.
+    expect(after.sleepingAgentSessionsByPaneKey[paneKey]).toBeDefined()
+  })
+
+  it('still resumes once the host has published the row without any live handle', () => {
+    const worktree = makeRuntimeOwnedWorktree()
+    seedMirroredWorkspace(worktree)
+    seedActiveSleepingRecord(worktree.id)
+    useAppStore.setState({ ptyIdsByTabId: { [WEB_TAB_ID]: ['remote:env-handle-gap@@other'] } })
+    markHostSessionMirrorHydrated(RUNTIME_ENV_ID)
+
+    expect(resumeSleepingAgentSessionsForWorktree(worktree.id)).toBe(1)
+  })
+})