fix: keep planning edits lossless across tabs (#373)

frontend/dashboard.js

@@ -135,6 +135,7 @@
   let activeMyWork = [];
   let laterMyWork = [];
   let todayMyWork = [];
+  const outboxCoordinator = createOutboxCoordinator({ storage: localStorage });
   const todayWork = createTodayWork({
     storage: localStorage,
     getLogin: () => planningOwnerLogin,
@@ -143,6 +144,7 @@
     storage: localStorage,
     getLogin: () => planningOwnerLogin,
     fetchJson: fetchReviewJson,
+    coordinator: outboxCoordinator,
     onRemoteIds: ids => {
       if (!planningOwnerLogin || !todayWork.replace(ids)) return;
       refreshMyWorkView();
@@ -177,6 +179,7 @@
     storage: localStorage,
     getLogin: () => planningOwnerLogin,
     fetchJson: fetchReviewJson,
+    coordinator: outboxCoordinator,
     onRemoteRecords: records => {
       if (!planningOwnerLogin || !laterWork.adopt(records)) return;
       refreshMyWorkView();
@@ -242,7 +245,6 @@
       await registration.sync.register('stackchain-issue-outbox-v1');
     };
   }
-  const outboxCoordinator = createOutboxCoordinator({ storage: localStorage });
   const issueOutbox = createIssueOutbox({
     storage: localStorage, fetchJson: fetchReviewJson, coordinator: outboxCoordinator,
     backgroundSync: backgroundIssueSync,

frontend/later-sync.js

@@ -1,4 +1,4 @@
-function createLaterSync({ storage, getLogin, fetchJson, onRemoteRecords, onStatus, createOperationId, createChannel,
+function createLaterSync({ storage, getLogin, fetchJson, onRemoteRecords, onStatus, createOperationId, createChannel, coordinator,
   setTimer = globalThis.setTimeout, clearTimer = globalThis.clearTimeout, retryBaseMs = 1000, retryMaxMs = 30000 }) {
   const prefix = 'stackchain.later-sync.v1.';
   const migrationPrefix = 'stackchain.later-sync-migrated.v1.';
@@ -8,6 +8,7 @@ function createLaterSync({ storage, getLogin, fetchJson, onRemoteRecords, onStat
   let channelKey = '';
   let retryTimer = null;
   let retryAttempt = 0;
+  const knownOperationKeys = new Set();
 
   function cancelRetry() {
     if (retryTimer !== null) clearTimer?.(retryTimer);
@@ -84,25 +85,52 @@ function createLaterSync({ storage, getLogin, fetchJson, onRemoteRecords, onStat
   function pending() {
     const storageKey = key();
     if (!storageKey || !storage) return [];
+    const recordPrefix = storageKey + '.operation.';
     try {
-      const value = JSON.parse(storage.getItem(storageKey) || '[]');
+      const legacy = JSON.parse(storage.getItem(storageKey) || '[]');
-      return Array.isArray(value) ? value.filter(operation =>
+      if (Array.isArray(legacy)) {
+        legacy.forEach((operation, index) => {
+          if (!operation?.operation_id) return;
+          const recordKey = recordPrefix + encodeURIComponent(operation.operation_id);
+          storage.setItem(recordKey, JSON.stringify({ operation, queued_at: index }));
+          knownOperationKeys.add(recordKey);
+        });
+        if (legacy.length) storage.removeItem(storageKey);
+      }
+      const keys = new Set([...knownOperationKeys].filter(candidate => candidate.startsWith(recordPrefix)));
+      for (let index = 0; index < Number(storage.length || 0); index += 1) {
+        const candidate = storage.key?.(index);
+        if (candidate?.startsWith(recordPrefix)) keys.add(candidate);
+      }
+      const records = [...keys].map(recordKey => {
+        const record = JSON.parse(storage.getItem(recordKey) || 'null');
+        return record ? { ...record, recordKey } : null;
+      }).filter(record => record?.operation)
+        .sort((left, right) => Number(left.queued_at || 0) - Number(right.queued_at || 0) ||
+          left.operation.operation_id.localeCompare(right.operation.operation_id));
+      const latestByItem = new Map();
+      records.forEach(record => latestByItem.set(record.operation.item_id, record));
+      records.filter(record => latestByItem.get(record.operation.item_id) !== record).forEach(record => {
+        storage.removeItem(record.recordKey);
+        knownOperationKeys.delete(record.recordKey);
+      });
+      return records.filter(record => latestByItem.get(record.operation.item_id) === record)
+        .map(record => record.operation).filter(operation =>
           operation && typeof operation.operation_id === 'string' &&
-        ['defer', 'restore'].includes(operation.action) &&
+          ['defer', 'restore'].includes(operation.action) && typeof operation.item_id === 'string' &&
-        typeof operation.item_id === 'string' &&
+          (operation.action === 'restore' || typeof operation.wake_at === 'string'));
-        (operation.action === 'restore' || typeof operation.wake_at === 'string')
-      ) : [];
     } catch (_error) {
       return [];
     }
   }
 
-  function save(operations) {
+  function removeOperation(operationId) {
     const storageKey = key();
     if (!storageKey || !storage) return false;
+    const recordKey = storageKey + '.operation.' + encodeURIComponent(operationId);
     try {
-      if (operations.length) storage.setItem(storageKey, JSON.stringify(operations));
+      storage.removeItem(recordKey);
-      else storage.removeItem(storageKey);
+      knownOperationKeys.delete(recordKey);
       return true;
     } catch (_error) {
       return false;
@@ -118,9 +146,19 @@ function createLaterSync({ storage, getLogin, fetchJson, onRemoteRecords, onStat
   function enqueue(action, itemId, wakeAt = null) {
     if (!['defer', 'restore'].includes(action) || !itemId ||
         (action === 'defer' && typeof wakeAt !== 'string')) return false;
-    const operations = pending().filter(operation => operation.item_id !== itemId);
+    pending().filter(operation => operation.item_id === itemId)
-    operations.push({ operation_id: operationId(), action, item_id: itemId, wake_at: wakeAt });
+      .forEach(operation => removeOperation(operation.operation_id));
-    const saved = save(operations);
+    const operation = { operation_id: operationId(), action, item_id: itemId, wake_at: wakeAt };
+    const storageKey = key();
+    if (!storageKey || !storage) return false;
+    const recordKey = storageKey + '.operation.' + encodeURIComponent(operation.operation_id);
+    let saved = false;
+    try {
+      storage.setItem(recordKey, JSON.stringify({ operation, queued_at: Date.now() }));
+      knownOperationKeys.add(recordKey);
+      saved = true;
+      coordinator?.notify('later');
+    } catch (_error) { /* Report the persistence failure below. */ }
     onStatus?.(saved ? 'pending' : 'error');
     return saved;
   }
@@ -156,9 +194,8 @@ function createLaterSync({ storage, getLogin, fetchJson, onRemoteRecords, onStat
           headers: { 'Content-Type': 'application/json' },
           body: JSON.stringify(operation),
         });
-        const remaining = pending();
+        if (pending().some(candidate => candidate.operation_id === operation.operation_id) &&
-        const delivered = remaining.findIndex(candidate => candidate.operation_id === operation.operation_id);
+            !removeOperation(operation.operation_id)) {
-        if (delivered >= 0 && !save(remaining.filter((_, index) => index !== delivered))) {
           throw new Error('Could not persist Later delivery receipt');
         }
         operations = pending();
@@ -176,7 +213,10 @@ function createLaterSync({ storage, getLogin, fetchJson, onRemoteRecords, onStat
   }
 
   function flush() {
-    if (!flushing) flushing = run().finally(() => { flushing = null; });
+    if (!flushing) {
+      const delivery = coordinator ? coordinator.runExclusive('later', run) : run();
+      flushing = Promise.resolve(delivery).finally(() => { flushing = null; });
+    }
     return flushing;
   }
 
@@ -187,6 +227,10 @@ function createLaterSync({ storage, getLogin, fetchJson, onRemoteRecords, onStat
     );
   }
 
+  coordinator?.subscribe(change => {
+    if (change.queue === 'later' && pending().length) flush();
+  });
+
   return { enqueue, migrate, flush, pending, startLifecycle };
 }
 

frontend/outbox-coordinator.js

@@ -15,7 +15,7 @@ function createOutboxCoordinator({
   let sequence = 0;
 
   function validChange(value) {
-    return value && (value.queue === 'issue' || value.queue === 'authored') ? value : null;
+    return value && ['issue', 'authored', 'today', 'later'].includes(value.queue) ? value : null;
   }
 
   function publish(change) {

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-v52';
+const CACHE = 'stackchain-dashboard-shell-v53';
 const OUTAGE_STATUSES = new Set([500, 502, 503, 504]);
 const NAVIGATION_TIMEOUT_MS = self.__STACKCHAIN_NAVIGATION_TIMEOUT_MS || 4000;
 const SHELL = [

frontend/today-sync.js

@@ -1,4 +1,4 @@
-function createTodaySync({ storage, getLogin, fetchJson, onRemoteIds, onStatus, createOperationId, createChannel,
+function createTodaySync({ storage, getLogin, fetchJson, onRemoteIds, onStatus, createOperationId, createChannel, coordinator,
   setTimer = globalThis.setTimeout, clearTimer = globalThis.clearTimeout, retryBaseMs = 1000, retryMaxMs = 30000 }) {
   const prefix = 'stackchain.today-sync.v1.';
   const migrationPrefix = 'stackchain.today-sync-migrated.v1.';
@@ -8,6 +8,7 @@ function createTodaySync({ storage, getLogin, fetchJson, onRemoteIds, onStatus,
   let channelKey = '';
   let retryTimer = null;
   let retryAttempt = 0;
+  const knownOperationKeys = new Set();
 
   function cancelRetry() {
     if (retryTimer !== null) clearTimer?.(retryTimer);
@@ -79,24 +80,42 @@ function createTodaySync({ storage, getLogin, fetchJson, onRemoteIds, onStatus,
   function pending() {
     const storageKey = key();
     if (!storageKey || !storage) return [];
+    const recordPrefix = storageKey + '.operation.';
     try {
-      const value = JSON.parse(storage.getItem(storageKey) || '[]');
+      const legacy = JSON.parse(storage.getItem(storageKey) || '[]');
-      return Array.isArray(value) ? value.filter(operation =>
+      if (Array.isArray(legacy)) {
-        operation && typeof operation.operation_id === 'string' &&
+        legacy.forEach((operation, index) => {
-        ['add', 'remove', 'move'].includes(operation.action) &&
+          if (!operation?.operation_id) return;
-        typeof operation.item_id === 'string'
+          const recordKey = recordPrefix + encodeURIComponent(operation.operation_id);
-      ) : [];
+          storage.setItem(recordKey, JSON.stringify({ operation, queued_at: index }));
+          knownOperationKeys.add(recordKey);
+        });
+        if (legacy.length) storage.removeItem(storageKey);
+      }
+      const keys = new Set([...knownOperationKeys].filter(candidate => candidate.startsWith(recordPrefix)));
+      for (let index = 0; index < Number(storage.length || 0); index += 1) {
+        const candidate = storage.key?.(index);
+        if (candidate?.startsWith(recordPrefix)) keys.add(candidate);
+      }
+      return [...keys].map(recordKey => JSON.parse(storage.getItem(recordKey) || 'null'))
+        .filter(record => record?.operation)
+        .sort((left, right) => Number(left.queued_at || 0) - Number(right.queued_at || 0) ||
+          left.operation.operation_id.localeCompare(right.operation.operation_id))
+        .map(record => record.operation)
+        .filter(operation => operation && typeof operation.operation_id === 'string' &&
+          ['add', 'remove', 'move'].includes(operation.action) && typeof operation.item_id === 'string');
     } catch (_error) {
       return [];
     }
   }
 
-  function save(operations) {
+  function removeOperation(operationId) {
     const storageKey = key();
     if (!storageKey || !storage) return false;
+    const recordKey = storageKey + '.operation.' + encodeURIComponent(operationId);
     try {
-      if (operations.length) storage.setItem(storageKey, JSON.stringify(operations));
+      storage.removeItem(recordKey);
-      else storage.removeItem(storageKey);
+      knownOperationKeys.delete(recordKey);
       return true;
     } catch (_error) {
       return false;
@@ -117,8 +136,17 @@ function createTodaySync({ storage, getLogin, fetchJson, onRemoteIds, onStatus,
       onStatus?.('pending');
       return true;
     }
-    operations.push({ operation_id: operationId(), action, item_id: itemId, direction });
+    const operation = { operation_id: operationId(), action, item_id: itemId, direction };
-    const saved = save(operations);
+    const storageKey = key();
+    if (!storageKey || !storage) return false;
+    const recordKey = storageKey + '.operation.' + encodeURIComponent(operation.operation_id);
+    let saved = false;
+    try {
+      storage.setItem(recordKey, JSON.stringify({ operation, queued_at: Date.now() }));
+      knownOperationKeys.add(recordKey);
+      saved = true;
+      coordinator?.notify('today');
+    } catch (_error) { /* Report the persistence failure below. */ }
     onStatus?.(saved ? 'pending' : 'error');
     return saved;
   }
@@ -156,17 +184,15 @@ function createTodaySync({ storage, getLogin, fetchJson, onRemoteIds, onStatus,
           });
         } catch (error) {
           if (error?.status !== 409) throw error;
-          const rejected = pending();
+          if (!removeOperation(operation.operation_id)) {
-          if (!save(rejected.filter(candidate => candidate.operation_id !== operation.operation_id))) {
             throw new Error('Could not persist rejected Today operation');
           }
           hadConflict = true;
           operations = pending();
           continue;
         }
-        const remaining = pending();
+        if (pending().some(candidate => candidate.operation_id === operation.operation_id) &&
-        const delivered = remaining.findIndex(candidate => candidate.operation_id === operation.operation_id);
+            !removeOperation(operation.operation_id)) {
-        if (delivered >= 0 && !save(remaining.filter((_, index) => index !== delivered))) {
           throw new Error('Could not persist Today delivery receipt');
         }
         operations = pending();
@@ -184,7 +210,10 @@ function createTodaySync({ storage, getLogin, fetchJson, onRemoteIds, onStatus,
   }
 
   function flush() {
-    if (!flushing) flushing = run().finally(() => { flushing = null; });
+    if (!flushing) {
+      const delivery = coordinator ? coordinator.runExclusive('today', run) : run();
+      flushing = Promise.resolve(delivery).finally(() => { flushing = null; });
+    }
     return flushing;
   }
 
@@ -195,6 +224,10 @@ function createTodaySync({ storage, getLogin, fetchJson, onRemoteIds, onStatus,
     );
   }
 
+  coordinator?.subscribe(change => {
+    if (change.queue === 'today' && pending().length) flush();
+  });
+
   return { enqueue, migrate, flush, pending, startLifecycle };
 }
 

tests/test_later_sync.py

@@ -9,6 +9,7 @@ from tests.dashboard_bundle import dashboard
 
 LATER_SYNC = Path(__file__).parents[1] / "frontend" / "later-sync.js"
 LATER_WORK = Path(__file__).parents[1] / "frontend" / "later-work.js"
+COORDINATOR = Path(__file__).parents[1] / "frontend" / "outbox-coordinator.js"
 
 
 def run_node(script):
@@ -19,6 +20,41 @@ def run_node(script):
     )
 
 
+def test_two_tabs_cannot_erase_each_others_later_edits_or_double_drain():
+    script = f"""
+const createLaterSync=require({json.dumps(str(LATER_SYNC))});
+const createCoordinator=require({json.dumps(str(COORDINATOR))});
+const values=new Map();const storage={{get length(){{return values.size}},key:i=>[...values.keys()][i]||null,getItem:k=>values.get(k)||null,setItem:(k,v)=>values.set(k,v),removeItem:k=>values.delete(k)}};
+const channels=[];const channelFactory=()=>{{const channel={{onmessage:null,postMessage:data=>channels.filter(x=>x!==channel).forEach(x=>x.onmessage?.({{data}})),close(){{}}}};channels.push(channel);return channel}};
+const held=new Set();const locks={{request:async(name,_options,work)=>{{if(held.has(name))return work(null);held.add(name);try{{return await work({{name}})}}finally{{held.delete(name)}}}}}};
+let sequence=0,releaseFirst;const delivered=[];
+const make=tab=>createLaterSync({{storage,getLogin:()=> 'timmy',createOperationId:()=>tab+'-'+(++sequence),coordinator:createCoordinator({{storage,locks,channelFactory,tabId:tab}}),fetchJson:async(_url,options={{}})=>{{if(!options.method)return {{revision:0,records:{{}}}};const operation=JSON.parse(options.body);delivered.push(operation);if(delivered.length===1)await new Promise(resolve=>releaseFirst=resolve);return {{revision:delivered.length,records:{{[operation.item_id]:operation.wake_at}}}}}},onRemoteRecords:()=>{{}},onStatus:()=>{{}}}});
+const first=make('first'),second=make('second');first.enqueue('defer','issue:r:1:','2026-08-10T09:00:00.000Z');
+(async()=>{{const draining=first.flush();while(!releaseFirst)await Promise.resolve();second.enqueue('defer','issue:r:2:','2026-08-11T09:00:00.000Z');const competing=second.flush();releaseFirst();await Promise.all([draining,competing]);await first.flush();process.stdout.write(JSON.stringify({{delivered,pending:first.pending(),keys:[...values.keys()]}}));}})();
+"""
+    result = run_node(script)
+    assert sorted(operation["operation_id"] for operation in result["delivered"]) == ["first-1", "second-2"]
+    assert len(result["delivered"]) == 2
+    assert result["pending"] == []
+    assert not any(".operation." in key for key in result["keys"])
+
+
+def test_concurrent_later_records_for_one_item_deliver_only_the_newest_intent():
+    script = f"""
+const createLaterSync=require({json.dumps(str(LATER_SYNC))});
+const values=new Map();const storage={{get length(){{return values.size}},key:i=>[...values.keys()][i]||null,getItem:k=>values.get(k)||null,setItem:(k,v)=>values.set(k,v),removeItem:k=>values.delete(k)}};
+const prefix='stackchain.later-sync.v1.timmy.operation.';
+values.set(prefix+'old',JSON.stringify({{queued_at:100,operation:{{operation_id:'old',action:'defer',item_id:'issue:r:2:',wake_at:'2026-08-10T09:00:00.000Z'}}}}));
+values.set(prefix+'new',JSON.stringify({{queued_at:101,operation:{{operation_id:'new',action:'restore',item_id:'issue:r:2:',wake_at:null}}}}));
+const delivered=[];const sync=createLaterSync({{storage,getLogin:()=> 'timmy',fetchJson:async(_url,options={{}})=>{{if(!options.method)return {{revision:0,records:{{}}}};delivered.push(JSON.parse(options.body));return {{revision:1,records:{{}}}}}},onRemoteRecords:()=>{{}},onStatus:()=>{{}}}});
+(async()=>{{await sync.flush();process.stdout.write(JSON.stringify({{delivered,pending:sync.pending(),keys:[...values.keys()]}}));}})();
+"""
+    result = run_node(script)
+    assert [operation["operation_id"] for operation in result["delivered"]] == ["new"]
+    assert result["pending"] == []
+    assert not any(".operation." in key for key in result["keys"])
+
+
 def test_offline_deferral_replays_once_and_adopts_server_records():
     script = f"""
 const createLaterSync = require({json.dumps(str(LATER_SYNC))});
@@ -233,5 +269,5 @@ async def test_dashboard_syncs_every_later_change_and_exposes_account_status():
 def test_later_sync_ships_atomically_in_the_offline_shell():
     source = (Path(__file__).parents[1] / "frontend" / "service-worker.js").read_text()
 
-    assert "stackchain-dashboard-shell-v52" in source
+    assert "stackchain-dashboard-shell-v53" in source
     assert "BASE + 'static/later-sync.js'" in source

tests/test_markdown_renderer.py

@@ -137,4 +137,4 @@ def test_markdown_work_bodies_are_mobile_safe_block_containers():
     assert ".markdown-content { min-width:0; max-width:100%; overflow-wrap:anywhere;" in css
     assert ".markdown-content pre { max-width:100%; overflow-x:auto;" in css
     assert ".markdown-content a { min-height:44px;" in css
-    assert "stackchain-dashboard-shell-v52" in worker
+    assert "stackchain-dashboard-shell-v53" in worker

tests/test_mobile_composer_integration.py

@@ -35,4 +35,4 @@ def test_offline_shell_contains_every_local_dashboard_runtime_asset():
     shell_assets = set(re.findall(r"BASE \+ '([^']+)'", worker.split("async function sessionCsrf", 1)[0]))
 
     assert local_assets <= shell_assets, f"Offline shell is missing: {sorted(local_assets - shell_assets)}"
-    assert "stackchain-dashboard-shell-v52" in worker
+    assert "stackchain-dashboard-shell-v53" in worker

tests/test_outbox_coordinator.py

@@ -110,13 +110,15 @@ const seen=[];
 const unsubscribe=second.subscribe(change=>seen.push(change));
 first.notify('issue');
 first.notify('authored');
+first.notify('today');
+first.notify('later');
 unsubscribe();
 first.notify('issue');
 process.stdout.write(JSON.stringify({{seen,signal:JSON.parse(storage.getItem('stackchain.outbox-change.v1'))}}));
 """
     output = run_node(script)
 
-    assert [change["queue"] for change in output["seen"]] == ["issue", "authored"]
+    assert [change["queue"] for change in output["seen"]] == ["issue", "authored", "today", "later"]
     assert output["signal"]["queue"] == "issue"
     assert output["signal"]["tabId"] == "first"
 

tests/test_service_worker.py

@@ -108,7 +108,7 @@ async function dispatchNotificationClick(route) {{
 def test_duplicate_aware_capture_ships_in_a_new_offline_shell():
     source = WORKER.read_text()
 
-    assert "stackchain-dashboard-shell-v52" in source
+    assert "stackchain-dashboard-shell-v53" in source
     assert "BASE + 'static/create-issue-sheet.js'" in source
     assert "BASE + 'static/dashboard.js'" in source
 
@@ -116,14 +116,14 @@ def test_duplicate_aware_capture_ships_in_a_new_offline_shell():
 def test_exact_later_picker_ships_atomically_in_a_new_offline_shell():
     source = WORKER.read_text()
 
-    assert "stackchain-dashboard-shell-v52" in source
+    assert "stackchain-dashboard-shell-v53" in source
     assert "BASE + 'static/later-picker.js'" in source
 
 
 def test_navigation_deadline_ships_in_a_new_shell_cache():
     source = WORKER.read_text()
 
-    assert "stackchain-dashboard-shell-v52" in source
+    assert "stackchain-dashboard-shell-v53" in source
     assert "BASE + 'static/dashboard.css'" in source
     assert "BASE + 'static/dashboard.js'" in source
     assert "BASE + 'static/install-app.js'" in source
@@ -132,21 +132,21 @@ def test_navigation_deadline_ships_in_a_new_shell_cache():
 def test_today_convergence_ships_in_a_new_shell_cache():
     source = WORKER.read_text()
 
-    assert "stackchain-dashboard-shell-v52" in source
+    assert "stackchain-dashboard-shell-v53" in source
     assert "BASE + 'static/today-sync.js'" in source
 
 
 def test_mobile_search_viewport_ships_in_a_new_offline_shell():
     source = WORKER.read_text()
 
-    assert "stackchain-dashboard-shell-v52" in source
+    assert "stackchain-dashboard-shell-v53" in source
     assert "BASE + 'static/mobile-search-viewport.js'" in source
 
 
 def test_update_ownership_flow_ships_atomically_in_a_new_offline_shell():
     source = WORKER.read_text()
 
-    assert "stackchain-dashboard-shell-v52" in source
+    assert "stackchain-dashboard-shell-v53" in source
     assert "BASE + 'static/update-ownership.js'" in source
 
 

tests/test_today_sync.py

@@ -4,6 +4,29 @@ from pathlib import Path
 
 
 TODAY_SYNC = Path(__file__).parents[1] / "frontend" / "today-sync.js"
+COORDINATOR = Path(__file__).parents[1] / "frontend" / "outbox-coordinator.js"
+
+
+def test_two_tabs_cannot_erase_each_others_today_edits_or_double_drain():
+    script = f"""
+const createTodaySync = require({json.dumps(str(TODAY_SYNC))});
+const createCoordinator = require({json.dumps(str(COORDINATOR))});
+const values = new Map();
+const storage = {{get length(){{return values.size}},key:i=>[...values.keys()][i]||null,
+ getItem:k=>values.get(k)||null,setItem:(k,v)=>values.set(k,v),removeItem:k=>values.delete(k)}};
+const channels=[]; const channelFactory=()=>{{const channel={{onmessage:null,postMessage:data=>channels.filter(x=>x!==channel).forEach(x=>x.onmessage?.({{data}})),close(){{}}}};channels.push(channel);return channel}};
+const held=new Set(); const locks={{request:async(name,_options,work)=>{{if(held.has(name))return work(null);held.add(name);try{{return await work({{name}})}}finally{{held.delete(name)}}}}}};
+let sequence=0,releaseFirst;const delivered=[];
+const make=tab=>createTodaySync({{storage,getLogin:()=> 'timmy',createOperationId:()=>tab+'-'+(++sequence),coordinator:createCoordinator({{storage,locks,channelFactory,tabId:tab}}),
+ fetchJson:async(_url,options={{}})=>{{if(!options.method)return {{revision:0,ids:[]}};const operation=JSON.parse(options.body);delivered.push(operation.operation_id);if(delivered.length===1)await new Promise(resolve=>releaseFirst=resolve);return {{revision:delivered.length,ids:delivered}}}},onRemoteIds:()=>{{}},onStatus:()=>{{}}}});
+const first=make('first'),second=make('second');first.enqueue('add','issue:r:1:');
+(async()=>{{const draining=first.flush();while(!releaseFirst)await Promise.resolve();second.enqueue('add','issue:r:2:');const competing=second.flush();releaseFirst();await Promise.all([draining,competing]);await first.flush();process.stdout.write(JSON.stringify({{delivered,pending:first.pending(),keys:[...values.keys()]}}));}})();
+"""
+    result = json.loads(subprocess.run(["node", "-e", script], check=True, capture_output=True, text=True).stdout)
+    assert sorted(result["delivered"]) == ["first-1", "second-2"]
+    assert len(result["delivered"]) == 2
+    assert result["pending"] == []
+    assert not any(".operation." in key for key in result["keys"])
 
 
 def test_operations_enqueued_during_an_inflight_flush_are_drained_before_it_settles():
@@ -63,7 +86,7 @@ sync.enqueue('add', 'issue:r:1:');
 def test_inflight_today_drain_ships_in_a_new_offline_shell():
     source = (Path(__file__).parents[1] / "frontend" / "service-worker.js").read_text()
 
-    assert "stackchain-dashboard-shell-v52" in source
+    assert "stackchain-dashboard-shell-v53" in source
     assert "BASE + 'static/today-sync.js'" in source