frontend/background-issue-sync.js

@@ -8,7 +8,14 @@ function createIndexedDbTransaction(indexedDB, dbName = 'stackchain-background-o
           request.result.createObjectStore('issues', { keyPath: 'id' });
         }
       };
-      request.onsuccess = () => resolve(request.result);
+      request.onsuccess = () => {
+        const db = request.result;
+        db.onversionchange = () => {
+          db.close();
+          databasePromise = undefined;
+        };
+        resolve(db);
+      };
       request.onerror = () => reject(request.error);
     });
     return databasePromise;
@@ -17,7 +24,7 @@ function createIndexedDbTransaction(indexedDB, dbName = 'stackchain-background-o
     request.onsuccess = () => resolve(request.result);
     request.onerror = () => reject(request.error);
   });
-  return async work => {
+  const transact = async work => {
     const db = await database();
     return new Promise((resolve, reject) => {
       const transaction = db.transaction('issues', 'readwrite');
@@ -38,6 +45,13 @@ function createIndexedDbTransaction(indexedDB, dbName = 'stackchain-background-o
       });
     });
   };
+  transact.close = async () => {
+    if (!databasePromise) return;
+    const db = await databasePromise;
+    db.close();
+    databasePromise = undefined;
+  };
+  return transact;
 }
 
 function createIssueSyncStore({ transaction, indexedDB = globalThis.indexedDB, now = () => Date.now(), claimMs = 30000 } = {}) {
@@ -149,10 +163,13 @@ function createIssueSyncStore({ transaction, indexedDB = globalThis.indexedDB, n
         item.status !== 'sent' && item.ownerLogin !== ownerLogin).length),
     setReceiptPreference,
     getReceiptPreference,
+    close: () => transact.close?.(),
   };
 }
 
 function createBackgroundIssueSync({ store, fetchJson, base = '' }) {
+  let purgeRequested = false;
+  let activeFlush = null;
   function receiptFor(item, status, delivered = {}) {
     if (status === 'attention') {
       return { id: item.id, status, kind: item.kind ? 'message' : 'issue', route: '#/my-work/drafts' };
@@ -238,6 +255,7 @@ function createBackgroundIssueSync({ store, fetchJson, base = '' }) {
   }
 
   async function send(item, currentLogin) {
+    if (purgeRequested) return { blocked: true };
     if (!currentLogin || item.ownerLogin !== currentLogin) return { blocked: true };
     await store.upsert(item);
     const claimed = await store.claim(item.id, currentLogin);
@@ -245,7 +263,7 @@ function createBackgroundIssueSync({ store, fetchJson, base = '' }) {
     return deliver(claimed);
   }
 
-  async function flush() {
+  async function runFlush() {
     const identity = await fetchJson(base + 'api/v1/background-identity', {
       headers: { Accept: 'application/json' }, cache: 'no-store',
     });
@@ -267,8 +285,21 @@ function createBackgroundIssueSync({ store, fetchJson, base = '' }) {
     return { confirmed, blocked, attention, login, receipts };
   }
 
+  function flush() {
+    if (purgeRequested) return Promise.resolve({ confirmed: [], blocked: 0, attention: 0, login: '', receipts: [] });
+    if (activeFlush) return activeFlush;
+    activeFlush = runFlush().finally(() => { activeFlush = null; });
+    return activeFlush;
+  }
+
+  async function purge() {
+    purgeRequested = true;
+    if (activeFlush) await activeFlush.catch(() => {});
+    await store.close?.();
+  }
+
   return {
-    flush, send,
+    flush, send, purge,
     reconcile: (items, outboxLane) => store.reconcile(items, outboxLane),
     snapshot: () => store.snapshot(),
     setReceiptPreference: (ownerLogin, enabled) => store.setReceiptPreference(ownerLogin, enabled),

frontend/service-worker.js

@@ -1,6 +1,6 @@
 const BASE = new URL('./', self.location.href).pathname;
 importScripts(BASE + 'static/background-issue-sync.js');
-const CACHE = 'stackchain-dashboard-shell-v24';
+const CACHE = 'stackchain-dashboard-shell-v25';
 const OUTAGE_STATUSES = new Set([500, 502, 503, 504]);
 const SHELL = [
   BASE,
@@ -100,6 +100,14 @@ self.addEventListener('sync', event => {
 
 self.addEventListener('message', event => {
   if (event.data?.type === 'stackchain-resume-outbox') event.waitUntil(flushAndNotify());
+  if (event.data?.type === 'stackchain-purge-outbox') event.waitUntil((async () => {
+    try {
+      await issueSync.purge();
+      event.ports?.[0]?.postMessage({ ok: true });
+    } catch (error) {
+      event.ports?.[0]?.postMessage({ ok: false, error: String(error?.message || 'Outbox purge failed.') });
+    }
+  })());
 });
 
 self.addEventListener('notificationclick', event => {

frontend/session.js

@@ -13,9 +13,14 @@
       indexedDB: root.indexedDB,
       caches: root.caches,
       serviceWorker: root.navigator?.serviceWorker,
+      MessageChannel: root.MessageChannel,
       location: root.location,
       confirmAction: message => root.confirm(message),
       onExpired: () => root.dispatchEvent(new CustomEvent('stackchain:session-expired')),
+      onClearError: error => {
+        root.dispatchEvent(new CustomEvent('stackchain:device-clear-failed', { detail: error.message }));
+        root.alert('Signed out, but private queued work could not be cleared. Close other Stackchain tabs and clear this site’s data.');
+      },
     });
     root.fetch = boundary.fetch;
     const attach = () => {
@@ -30,8 +35,9 @@
     root.stackchainSession = boundary;
   }
 })(typeof window !== 'undefined' ? window : this, function createSessionBoundary({
-  cookie, origin, base, fetchImpl, localStorage, sessionStorage, indexedDB, caches, serviceWorker, location, confirmAction,
+  cookie, origin, base, fetchImpl, localStorage, sessionStorage, indexedDB, caches, serviceWorker, MessageChannel, location, confirmAction,
   onExpired = () => {},
+  onClearError = () => {},
 }) {
   const SAFE_METHODS = new Set(['GET', 'HEAD', 'OPTIONS']);
 
@@ -73,11 +79,44 @@
     } catch (_error) { /* Cookie invalidation still protects server data. */ }
   }
 
+  async function stopWorkerOutbox() {
+    const registration = await serviceWorker?.ready;
+    if (!registration?.active || !MessageChannel) return;
+    await new Promise((resolve, reject) => {
+      const channel = new MessageChannel();
+      const timeout = setTimeout(() => reject(new Error('Background outbox purge timed out.')), 3000);
+      channel.port1.onmessage = event => {
+        clearTimeout(timeout);
+        if (event.data?.ok) resolve();
+        else reject(new Error(event.data?.error || 'Background outbox purge failed.'));
+      };
+      registration.active.postMessage({ type: 'stackchain-purge-outbox' }, [channel.port2]);
+    });
+  }
+
+  function deletePrivateOutbox() {
+    if (!indexedDB) return Promise.resolve();
+    return new Promise((resolve, reject) => {
+      let request;
+      try { request = indexedDB.deleteDatabase('stackchain-background-outbox-v1'); }
+      catch (error) { reject(error); return; }
+      request.onsuccess = () => resolve();
+      request.onerror = () => reject(request.error || new Error('IndexedDB deletion failed.'));
+      request.onblocked = () => reject(new Error('IndexedDB deletion was blocked.'));
+    });
+  }
+
   async function clearPrivateDeviceData() {
     removeDashboardStorage(localStorage);
     if (sessionStorage !== localStorage) removeDashboardStorage(sessionStorage);
-    try { indexedDB?.deleteDatabase('stackchain-background-outbox-v1'); }
-    catch (_error) { /* Continue clearing other dashboard state. */ }
+    try {
+      await stopWorkerOutbox();
+      await deletePrivateOutbox();
+    } catch (_error) {
+      const error = new Error('Could not clear private queued work from this device.');
+      onClearError(error);
+      throw error;
+    }
     try {
       const keys = await caches?.keys?.() || [];
       await Promise.all(keys.filter(key => key.startsWith('stackchain-dashboard-')).map(key => caches.delete(key)));

tests/test_background_issue_sync.py

@@ -194,6 +194,39 @@ const transaction=work=>{{const run=tail.then(()=>work({{
     ]
 
 
+def test_indexeddb_store_closes_on_version_change_and_reopens_afterward():
+    script = f"""
+const createBackgroundIssueSync = require({json.dumps(str(SYNC))});
+const state={{opens:0,closes:0}};
+const indexedDB={{lastDb:null,open:()=>{{
+  state.opens += 1;
+  const request={{result:null,onsuccess:null,onerror:null,onupgradeneeded:null}};
+  const db={{
+    objectStoreNames:{{contains:()=>true}},
+    close:()=>{{state.closes += 1;}},
+    transaction:()=>{{
+      const tx={{oncomplete:null,onerror:null,onabort:null,error:null,objectStore:()=>({{
+        getAll:()=>{{const get={{onsuccess:null,onerror:null,result:[]}};queueMicrotask(()=>get.onsuccess?.());return get;}},
+      }})}};
+      setTimeout(()=>tx.oncomplete?.(),0);
+      return tx;
+    }},
+  }};
+  indexedDB.lastDb=db;request.result=db;queueMicrotask(()=>request.onsuccess?.());return request;
+}}}};
+(async()=>{{
+  const store=createBackgroundIssueSync.createIssueSyncStore({{indexedDB}});
+  await store.snapshot();
+  indexedDB.lastDb.onversionchange?.();
+  await store.snapshot();
+  process.stdout.write(JSON.stringify(state));
+}})();
+"""
+    output = run_node(script)
+
+    assert output == {"opens": 2, "closes": 1}
+
+
 def test_delivery_receipt_preference_is_account_bound_and_hidden_from_outbox():
     script = f"""
 const createBackgroundIssueSync = require({json.dumps(str(SYNC))});

tests/test_dashboard_session_frontend.py

@@ -14,7 +14,7 @@ SESSION_JS = ROOT / "frontend" / "session.js"
 def run_session_scenario(scenario: str) -> dict:
     harness = f"""
 const createSessionBoundary = require({json.dumps(str(SESSION_JS))});
-const state = {{ requests: [], removed: [], deletedDatabases: [], deletedCaches: [], assigned: '', workerMessages: [], confirmations: [] }};
+const state = {{ requests: [], removed: [], deletedDatabases: [], deletionCompleted: false, deletedCaches: [], assigned: '', assignedAfterDeletion: false, workerMessages: [], confirmations: [], clearErrors: [] }};
 const storage = {{
   values: new Map([['stackchain.private', 'secret'], ['gitea.preference', 'keep']]),
   get length() {{ return this.values.size; }},
@@ -31,10 +31,24 @@ const boundary = createSessionBoundary({{
   }},
   localStorage: storage,
   sessionStorage: storage,
-  indexedDB: {{ deleteDatabase: name => {{ state.deletedDatabases.push(name); return {{ onsuccess: null, onerror: null, onblocked: null }}; }} }},
+  indexedDB: {{ deleteDatabase: name => {{
+    state.deletedDatabases.push(name);
+    const request = {{ onsuccess: null, onerror: null, onblocked: null, error: null }};
+    setTimeout(() => {{
+      if (state.failDeletion) {{ request.error = new Error('database blocked'); request.onerror?.(); }}
+      else {{ state.deletionCompleted = true; request.onsuccess?.(); }}
+    }}, 20);
+    return request;
+  }} }},
   caches: {{ keys: async () => ['stackchain-dashboard-shell-v15', 'gitea-assets'], delete: async key => {{ state.deletedCaches.push(key); }} }},
-  serviceWorker: {{ ready: Promise.resolve({{ active: {{ postMessage: message => state.workerMessages.push(message) }} }}) }},
-  location: {{ assign: value => {{ state.assigned = value; }} }},
+  serviceWorker: {{ ready: Promise.resolve({{ active: {{ postMessage: (message, ports = []) => {{ state.workerMessages.push(message); ports[0]?.postMessage({{ok:true}}); }} }} }}) }},
+  MessageChannel: class {{ constructor() {{
+    const first = {{ onmessage: null, postMessage: data => queueMicrotask(() => second.onmessage?.({{data}})) }};
+    const second = {{ onmessage: null, postMessage: data => queueMicrotask(() => first.onmessage?.({{data}})) }};
+    this.port1 = first; this.port2 = second;
+  }} }},
+  location: {{ assign: value => {{ state.assigned = value; state.assignedAfterDeletion = state.deletionCompleted; }} }},
+  onClearError: error => state.clearErrors.push(error.message),
   confirmAction: message => {{ state.confirmations.push(message); return true; }},
 }});
 (async () => {{ {scenario} }})().catch(error => {{ console.error(error); process.exit(1); }});
@@ -72,6 +86,21 @@ process.stdout.write(JSON.stringify(state));
     assert result["deletedDatabases"] == ["stackchain-background-outbox-v1"]
     assert result["deletedCaches"] == ["stackchain-dashboard-shell-v15"]
     assert result["assigned"] == "/dashboard/login"
+    assert result["assignedAfterDeletion"] is True
+
+
+def test_sign_out_stays_on_page_and_reports_failed_private_outbox_deletion():
+    result = run_session_scenario(
+        """
+state.failDeletion = true;
+try { await boundary.signOut(); } catch (error) { state.signOutError = error.message; }
+process.stdout.write(JSON.stringify(state));
+"""
+    )
+
+    assert result["assigned"] == ""
+    assert result["clearErrors"] == ["Could not clear private queued work from this device."]
+    assert result["signOutError"] == "Could not clear private queued work from this device."
 
 
 def test_sign_out_all_devices_requires_confirmation_and_uses_global_endpoint():

tests/test_service_worker.py

@@ -13,7 +13,7 @@ def run_worker_scenario(scenario: str) -> dict:
 const fs = require('fs');
 const vm = require('vm');
 const listeners = {{}};
-const state = {{ added: [], deleted: [], claimed: false, skipped: false, fetches: [], puts: [], backgroundFlushes: 0, notifications: [], focused: [], opened: [], failFetch: false, fetchStatus: 200, cachedBody: null }};
+const state = {{ added: [], deleted: [], claimed: false, skipped: false, fetches: [], puts: [], backgroundFlushes: 0, outboxPurges: 0, notifications: [], focused: [], opened: [], failFetch: false, fetchStatus: 200, cachedBody: null }};
 const cache = {{
   addAll: async urls => {{ state.added = urls; }},
   match: async request => state.cachedBody === null ? null : new Response(state.cachedBody),
@@ -34,6 +34,7 @@ const context = {{
     registration: {{showNotification: async (title, options) => state.notifications.push({{title,options}})}},
     __issueSync: {{
       flush: async () => {{ state.backgroundFlushes += 1; return state.flushResult; }},
+      purge: async () => {{ state.outboxPurges += 1; }},
       getReceiptPreference: async login => state.receiptLogin === login,
     }},
   }},
@@ -68,9 +69,9 @@ async function dispatchSync(tag) {{
   listeners.sync({{ tag, waitUntil: promise => {{ pending = promise; }} }});
   if (pending) await pending;
 }}
-async function dispatchMessage(data) {{
+async function dispatchMessage(data, ports = []) {{
   let pending;
-  listeners.message({{ data, waitUntil: promise => {{ pending = promise; }} }});
+  listeners.message({{ data, ports, waitUntil: promise => {{ pending = promise; }} }});
   if (pending) await pending;
 }}
 async function dispatchNotificationClick(route) {{
@@ -94,7 +95,7 @@ async function dispatchNotificationClick(route) {{
 def test_mobile_install_flow_ships_in_a_new_shell_cache():
     source = WORKER.read_text()
 
-    assert "stackchain-dashboard-shell-v24" in source
+    assert "stackchain-dashboard-shell-v25" in source
     assert "BASE + 'static/install-app.js'" in source
 
 
@@ -121,6 +122,19 @@ def test_authenticated_page_message_resumes_queued_background_delivery():
     assert result["backgroundFlushes"] == 1
 
 
+def test_device_purge_message_stops_worker_outbox_and_acknowledges_completion():
+    result = run_worker_scenario(
+        """
+  const replies = [];
+  await dispatchMessage({type:'stackchain-purge-outbox'}, [{postMessage: value => replies.push(value)}]);
+  process.stdout.write(JSON.stringify({state,replies}));
+"""
+    )
+
+    assert result["state"]["outboxPurges"] == 1
+    assert result["replies"] == [{"ok": True}]
+
+
 def test_opted_in_background_sync_notifies_privately_and_receipt_tap_focuses_route():
     result = run_worker_scenario(
         """