Merge pull request #2035 from code-yeongyu/fix/background-agent-review-feedback

fix: address Oracle + Cubic review feedback for background-agent refactoring

src/features/background-agent/compaction-aware-message-resolver.test.ts

@@ -96,8 +96,8 @@ describe("findNearestMessageExcludingCompaction", () => {
         agent: "sisyphus",
         model: { providerID: "anthropic", modelID: "claude-opus-4-6" },
       }
-      writeFileSync(join(tempDir, "001.json"), JSON.stringify(compactionMessage))
+      writeFileSync(join(tempDir, "002.json"), JSON.stringify(compactionMessage))
-      writeFileSync(join(tempDir, "002.json"), JSON.stringify(validMessage))
+      writeFileSync(join(tempDir, "001.json"), JSON.stringify(validMessage))
 
       // when
       const result = findNearestMessageExcludingCompaction(tempDir)
@@ -155,8 +155,8 @@ describe("findNearestMessageExcludingCompaction", () => {
         agent: "oracle",
         model: { providerID: "google", modelID: "gemini-2-flash" },
       }
-      writeFileSync(join(tempDir, "001.json"), invalidJson)
+      writeFileSync(join(tempDir, "002.json"), invalidJson)
-      writeFileSync(join(tempDir, "002.json"), JSON.stringify(validMessage))
+      writeFileSync(join(tempDir, "001.json"), JSON.stringify(validMessage))
 
       // when
       const result = findNearestMessageExcludingCompaction(tempDir)

src/features/background-agent/fallback-retry-handler.ts

@@ -117,6 +117,7 @@ export function tryFallbackRetry(args: {
     model: task.model,
     fallbackChain: task.fallbackChain,
     category: task.category,
+    isUnstableAgent: task.isUnstableAgent,
   }
   queue.push({ task, input: retryInput })
   queuesByKey.set(key, queue)

src/features/background-agent/manager.ts

@@ -9,7 +9,6 @@ import { TaskHistory } from "./task-history"
 import {
   log,
   getAgentToolRestrictions,
-  getMessageDir,
   normalizePromptTools,
   normalizeSDKResponse,
   promptWithModelSuggestionRetry,
@@ -44,6 +43,8 @@ import {
 import { tryFallbackRetry } from "./fallback-retry-handler"
 import { registerManagerForCleanup, unregisterManagerForCleanup } from "./process-cleanup"
 import { isCompactionAgent, findNearestMessageExcludingCompaction } from "./compaction-aware-message-resolver"
+import { MESSAGE_STORAGE } from "../hook-message-injector"
+import { join } from "node:path"
 import { pruneStaleTasksAndNotifications } from "./task-poller"
 import { checkAndInterruptStaleTasks } from "./task-poller"
 
@@ -931,6 +932,7 @@ export class BackgroundManager {
     errorInfo: { name?: string; message?: string },
     source: string,
   ): boolean {
+    const previousSessionID = task.sessionID
     const result = tryFallbackRetry({
       task,
       errorInfo,
@@ -941,8 +943,8 @@ export class BackgroundManager {
       queuesByKey: this.queuesByKey,
       processKey: (key: string) => this.processKey(key),
     })
-    if (result && task.sessionID) {
+    if (result && previousSessionID) {
-      subagentSessions.delete(task.sessionID)
+      subagentSessions.delete(previousSessionID)
     }
     return result
   }
@@ -1345,7 +1347,7 @@ Use \`background_output(task_id="${task.id}")\` to retrieve this result when rea
               parentSessionID: task.parentSessionID,
             })
           }
-          const messageDir = getMessageDir(task.parentSessionID)
+          const messageDir = join(MESSAGE_STORAGE, task.parentSessionID)
           const currentMessage = messageDir ? findNearestMessageExcludingCompaction(messageDir) : null
           agent = currentMessage?.agent ?? task.parentAgent
           model = currentMessage?.model?.providerID && currentMessage?.model?.modelID

src/features/background-agent/process-cleanup.test.ts

@@ -64,7 +64,9 @@ describe("process-cleanup", () => {
 
       registerManagerForCleanup(manager)
 
-      const [, listener] = processOnCalls[0]
+      const exitEntry = processOnCalls.find(([signal]) => signal === "exit")
+      expect(exitEntry).toBeDefined()
+      const [, listener] = exitEntry!
       listener()
 
       expect(mockShutdown).toHaveBeenCalled()
@@ -83,7 +85,9 @@ describe("process-cleanup", () => {
       registerManagerForCleanup(manager2)
       registerManagerForCleanup(manager3)
 
-      const [, listener] = processOnCalls[0]
+      const exitEntry = processOnCalls.find(([signal]) => signal === "exit")
+      expect(exitEntry).toBeDefined()
+      const [, listener] = exitEntry!
       listener()
 
       expect(shutdown1).toHaveBeenCalledTimes(1)
@@ -144,7 +148,9 @@ describe("process-cleanup", () => {
       registerManagerForCleanup(manager1)
       registerManagerForCleanup(manager2)
 
-      const [, listener] = processOnCalls[0]
+      const exitEntry = processOnCalls.find(([signal]) => signal === "exit")
+      expect(exitEntry).toBeDefined()
+      const [, listener] = exitEntry!
       unregisterManagerForCleanup(manager2)
 
       listener()

src/features/background-agent/process-cleanup.ts

@@ -11,7 +11,7 @@ function registerProcessSignal(
     handler()
     if (exitAfter) {
       process.exitCode = 0
-      setTimeout(() => process.exit(), 6000)
+      setTimeout(() => process.exit(), 6000).unref()
     }
   }
   process.on(signal, listener)