fix(background-agent): prevent false task completion on status API outage

Ultraworked with [Sisyphus](https://github.com/code-yeongyu/oh-my-openagent)

Co-authored-by: Sisyphus <clio-agent@sisyphuslabs.ai>

src/features/background-agent/manager.polling.test.ts

@@ -4,8 +4,25 @@ import { describe, test, expect, mock } from "bun:test"
 import { tmpdir } from "node:os"
 import type { PluginInput } from "@opencode-ai/plugin"
 import { BackgroundManager } from "./manager"
+import { MIN_SESSION_GONE_POLLS } from "./session-existence"
 import type { BackgroundTask } from "./types"
 
+function createPluginContext(client: object): PluginInput {
+  const directory = tmpdir()
+  return {
+    project: {
+      id: "test-project",
+      worktree: directory,
+      time: { created: Date.now() },
+    },
+    directory,
+    worktree: directory,
+    serverUrl: new URL("http://localhost:4096"),
+    $: {} as PluginInput["$"],
+    client: client as PluginInput["client"],
+  }
+}
+
 function createManagerWithStatus(statusImpl: () => Promise<{ data: Record<string, { type: string }> }>): BackgroundManager {
   const client = {
     session: {
@@ -18,7 +35,7 @@ function createManagerWithStatus(statusImpl: () => Promise<{ data: Record<string
     },
   }
 
-  return new BackgroundManager({ pluginContext: { client, directory: tmpdir() } as unknown as PluginInput })
+  return new BackgroundManager({ pluginContext: createPluginContext(client) })
 }
 
 describe("BackgroundManager polling overlap", () => {
@@ -42,9 +59,9 @@ describe("BackgroundManager polling overlap", () => {
     })
 
     //#when
-    const firstPoll = (manager as unknown as { pollRunningTasks: () => Promise<void> }).pollRunningTasks()
+    const firstPoll = manager["pollRunningTasks"]()
     await Promise.resolve()
-    const secondPoll = (manager as unknown as { pollRunningTasks: () => Promise<void> }).pollRunningTasks()
+    const secondPoll = manager["pollRunningTasks"]()
     releaseStatus?.()
     await Promise.all([firstPoll, secondPoll])
     manager.shutdown()
@@ -72,8 +89,7 @@ function createRunningTask(sessionId: string): BackgroundTask {
 }
 
 function injectTask(manager: BackgroundManager, task: BackgroundTask): void {
-  const tasks = (manager as unknown as { tasks: Map<string, BackgroundTask> }).tasks
-  tasks.set(task.id, task)
+  manager["tasks"].set(task.id, task)
 }
 
 function createManagerWithClient(clientOverrides: Record<string, unknown> = {}): BackgroundManager {
@@ -98,7 +114,7 @@ function createManagerWithClient(clientOverrides: Record<string, unknown> = {}):
     },
   }
   return new BackgroundManager(
-    { pluginContext: { client, directory: tmpdir() } as unknown as PluginInput, config: undefined, enableParentSessionNotifications: false },
+    { pluginContext: createPluginContext(client), config: undefined, enableParentSessionNotifications: false },
   )
 }
 
@@ -151,7 +167,7 @@ describe("BackgroundManager pollRunningTasks", () => {
       injectTask(manager, task)
 
       //#when
-      const poll = (manager as unknown as { pollRunningTasks: () => Promise<void> }).pollRunningTasks
+      const poll = manager["pollRunningTasks"]
       await poll.call(manager)
       manager.shutdown()
 
@@ -184,6 +200,62 @@ describe("BackgroundManager pollRunningTasks", () => {
       expect(task.consecutiveMissedPolls).toBe(1)
       expect(getSession).not.toHaveBeenCalled()
     })
+
+    test("#when status polling is unavailable #then it does not complete or increment missed polls", async () => {
+      const cases: Array<{ name: string; status?: (() => Promise<{ data: Record<string, { type: string }> }>) | undefined }> = [
+        { name: "missing status method", status: undefined },
+        { name: "throwing status method", status: async () => { throw new Error("status unavailable") } },
+      ]
+
+      for (const testCase of cases) {
+        //#given
+        let abortCallCount = 0
+        const manager = createManagerWithClient({
+          status: testCase.status,
+          abort: async () => {
+            abortCallCount += 1
+            return {}
+          },
+        })
+        const task = createRunningTask(`ses-${testCase.name.replace(/ /g, "-")}`)
+        injectTask(manager, task)
+
+        //#when
+        const poll = manager["pollRunningTasks"]
+        for (let count = 0; count < MIN_SESSION_GONE_POLLS + 1; count += 1) {
+          await poll.call(manager)
+        }
+
+        //#then
+        expect(task.status).toBe("running")
+        expect(task.completedAt).toBeUndefined()
+        expect(task.error).toBeUndefined()
+        expect(task.consecutiveMissedPolls ?? 0).toBe(0)
+        expect(abortCallCount).toBe(0)
+
+        await manager.shutdown()
+      }
+    })
+
+    test("#when reliable status polling omits the session #then it completes through the session-gone path", async () => {
+      //#given
+      const manager = createManagerWithClient({
+        status: async () => ({ data: {} }),
+      })
+      const task = createRunningTask("ses-reliably-gone")
+      injectTask(manager, task)
+
+      //#when
+      const poll = manager["pollRunningTasks"]
+      for (let count = 0; count < MIN_SESSION_GONE_POLLS; count += 1) {
+        await poll.call(manager)
+      }
+      await manager.shutdown()
+
+      //#then
+      expect(task.status).toBe("completed")
+      expect(task.completedAt).toBeDefined()
+    })
   })
 
   describe("#given a running task whose session status is idle", () => {
@@ -196,7 +268,7 @@ describe("BackgroundManager pollRunningTasks", () => {
       injectTask(manager, task)
 
       //#when
-      const poll = (manager as unknown as { pollRunningTasks: () => Promise<void> }).pollRunningTasks
+      const poll = manager["pollRunningTasks"]
       await poll.call(manager)
       manager.shutdown()
 
@@ -228,7 +300,7 @@ describe("BackgroundManager pollRunningTasks", () => {
       })
 
       //#when
-      const poll = (manager as unknown as { pollRunningTasks: () => Promise<void> }).pollRunningTasks
+      const poll = manager["pollRunningTasks"]
       await poll.call(manager)
       manager.shutdown()
 
@@ -265,7 +337,7 @@ describe("BackgroundManager pollRunningTasks", () => {
       })
 
       //#when
-      const poll = (manager as unknown as { pollRunningTasks: () => Promise<void> }).pollRunningTasks
+      const poll = manager["pollRunningTasks"]
       await poll.call(manager)
       manager.shutdown()
 
@@ -285,7 +357,7 @@ describe("BackgroundManager pollRunningTasks", () => {
       injectTask(manager, task)
 
       //#when
-      const poll = (manager as unknown as { pollRunningTasks: () => Promise<void> }).pollRunningTasks
+      const poll = manager["pollRunningTasks"]
       await poll.call(manager)
       manager.shutdown()
 
@@ -304,7 +376,7 @@ describe("BackgroundManager pollRunningTasks", () => {
       injectTask(manager, task)
 
       //#when
-      const poll = (manager as unknown as { pollRunningTasks: () => Promise<void> }).pollRunningTasks
+      const poll = manager["pollRunningTasks"]
       await poll.call(manager)
       manager.shutdown()
 
@@ -322,7 +394,7 @@ describe("BackgroundManager pollRunningTasks", () => {
       injectTask(manager, task)
 
       //#when
-      const poll = (manager as unknown as { pollRunningTasks: () => Promise<void> }).pollRunningTasks
+      const poll = manager["pollRunningTasks"]
       await poll.call(manager)
       manager.shutdown()