fix(worker): make user-box lifecycle concurrency-safe

apps/agent-worker/src/worker.ts

@@ -16,6 +16,7 @@ import { api } from '@spoon/backend/convex/_generated/api.js';
 
 import type { NormalizedAgentEvent } from './agent-events';
 import type { OpenCodeSession } from './opencode-session';
+import type { BoxHandle } from './user-container';
 import { normalizeCodexJsonLine } from './agent-events';
 import { prepareCodexWorkspaceFiles } from './codex-runtime';
 import { env } from './env';
@@ -41,11 +42,7 @@ import {
   stopWorkspaceContainer,
   streamExecInContainer,
 } from './runtime/docker';
-import {
-  acquireUserBox,
-  releaseUserBox,
-  runningBoxUsernames,
-} from './user-container';
+import { acquireUserBox, runningBoxUsernames } from './user-container';
 import { fetchUserEnvironment, materializeUserHome } from './user-environment';
 
 type Claim = {
@@ -111,6 +108,7 @@ type ActiveWorkspace = {
   repoDir: string;
   // Phase 2: the per-user box container this thread execs into.
   boxName: string;
+  boxHandle: BoxHandle;
   githubToken: string;
   redact: (value: string) => string;
   runtimeMode?: 'opencode_server' | 'codex_exec' | 'legacy_cli';
@@ -1323,7 +1321,7 @@ const runClaim = async (claim: Claim) => {
     ...claim.secrets.map((secret) => secret.value),
   ].filter(Boolean);
   const redact = createRedactor(secretValues);
-  let acquiredBoxUser: string | undefined;
+  let acquiredBoxHandle: BoxHandle | undefined;
   try {
     if ((claim.job.runtime ?? 'opencode') !== 'opencode') {
       throw new Error('Legacy OpenAI direct jobs are no longer supported.');
@@ -1354,12 +1352,13 @@ const runClaim = async (claim: Claim) => {
 
     // Start (or reuse) the persistent per-user box that this thread — and the
     // terminal — exec into. It mounts the home, so the clone below is visible.
-    const boxName = await acquireUserBox({
+    const boxHandle = await acquireUserBox({
       username,
       workdir: homeDir,
       containerHome,
     });
-    acquiredBoxUser = username;
+    acquiredBoxHandle = boxHandle;
+    const boxName = boxHandle.boxName;
 
     const repoDir = await cloneRepository({
       workdir: checkoutParent,
@@ -1381,6 +1380,7 @@ const runClaim = async (claim: Claim) => {
       containerRepo,
       repoDir,
       boxName,
+      boxHandle,
       githubToken,
       redact,
     };
@@ -1460,7 +1460,7 @@ const runClaim = async (claim: Claim) => {
     ).catch((stopError: unknown) => {
       console.error(stopError);
     });
-    if (acquiredBoxUser) releaseUserBox(acquiredBoxUser);
+    acquiredBoxHandle?.release();
   }
 };
 
@@ -1883,7 +1883,7 @@ export const openWorkspacePullRequest = async (jobId: string) => {
   activeWorkspaces.delete(jobId);
   // The persistent per-user home + ~/Code checkouts survive across sessions;
   // release the box (reaped once no other thread/terminal holds it).
-  releaseUserBox(workspace.username);
+  workspace.boxHandle.release();
   return {
     pullRequestUrl: pullRequest.html_url,
     pullRequestNumber: pullRequest.number,
@@ -1900,7 +1900,7 @@ export const stopWorkspace = async (jobId: string) => {
   activeWorkspaces.delete(jobId);
   // The persistent per-user home + ~/Code checkouts survive across sessions;
   // release the box (reaped once no other thread/terminal holds it).
-  releaseUserBox(workspace.username);
+  workspace.boxHandle.release();
   return { success: true };
 };