From faed1591eff13d072b3c778fc3fa5b8d8712309e Mon Sep 17 00:00:00 2001
From: Linus Rath <minipixxelinfo@gmail.com>
Date: Mon, 7 Sep 2026 22:34:47 +0200
Subject: [PATCH] fix: fail fast when the plugin storage database is blocked
 #840

---
 lib/__tests__/plugin-storage-blocked.test.ts | 59 ++++++++++++++++++++
 lib/plugin-storage.ts                        | 39 +++++++++++--
 2 files changed, 93 insertions(+), 5 deletions(-)
 create mode 100644 lib/__tests__/plugin-storage-blocked.test.ts

diff --git a/lib/__tests__/plugin-storage-blocked.test.ts b/lib/__tests__/plugin-storage-blocked.test.ts
new file mode 100644
index 000000000..4567b23b7
--- /dev/null
+++ b/lib/__tests__/plugin-storage-blocked.test.ts
@@ -0,0 +1,59 @@
+import { describe, it, expect } from 'vitest';
+import 'fake-indexeddb/auto';
+import { fileStorage } from '../plugin-storage';
+
+const DB_NAME = 'bulwark-plugins';
+// One below the version plugin-storage.ts opens, simulating an older tab.
+const PREVIOUS_DB_VERSION = 2;
+
+function openAt(version: number): Promise<IDBDatabase> {
+  return new Promise((resolve, reject) => {
+    const req = indexedDB.open(DB_NAME, version);
+    req.onsuccess = () => resolve(req.result);
+    req.onerror = () => reject(req.error);
+  });
+}
+
+describe('plugin storage when the upgrade is blocked (#840)', () => {
+  it('rejects saveFile instead of hanging while an older tab keeps the DB open', async () => {
+    // An "older tab" that never reacts to versionchange, so the upgrade to the
+    // current DB_VERSION cannot proceed.
+    const olderTab = await openAt(PREVIOUS_DB_VERSION);
+    expect(olderTab.version).toBe(PREVIOUS_DB_VERSION);
+
+    const file = new File(['hello'], 'hello.txt', { type: 'text/plain' });
+    const outcome = await Promise.race([
+      fileStorage.saveFile('blocked-file', file).then(
+        () => 'resolved',
+        (err: unknown) => (err instanceof Error ? err.message : String(err)),
+      ),
+      new Promise<string>((resolve) => setTimeout(() => resolve('timeout'), 2000)),
+    ]);
+
+    expect(outcome).not.toBe('timeout');
+    expect(outcome).not.toBe('resolved');
+    expect(outcome).toMatch(/blocked/i);
+
+    olderTab.close();
+  });
+
+  it('closes its own connection so a later upgrade is not blocked by it', async () => {
+    const file = new File(['hello'], 'hello.txt', { type: 'text/plain' });
+    await fileStorage.saveFile('closed-file', file);
+    expect(await fileStorage.getFile('closed-file')).not.toBeNull();
+
+    // If plugin-storage left its connection open, opening at a higher version
+    // would fire `blocked` (no onversionchange handler on a foreign handle);
+    // with the fix the module closes after every transaction.
+    const blocked = await new Promise<boolean>((resolve, reject) => {
+      const req = indexedDB.open(DB_NAME, 99);
+      req.onblocked = () => resolve(true);
+      req.onsuccess = () => {
+        req.result.close();
+        resolve(false);
+      };
+      req.onerror = () => reject(req.error);
+    });
+    expect(blocked).toBe(false);
+  });
+});
diff --git a/lib/plugin-storage.ts b/lib/plugin-storage.ts
index 988636667..5ce4b5dd5 100644
--- a/lib/plugin-storage.ts
+++ b/lib/plugin-storage.ts
@@ -32,8 +32,23 @@ function openDB(): Promise<IDBDatabase> {
       }
     };
 
-    request.onsuccess = () => resolve(request.result);
+    request.onsuccess = () => {
+      const db = request.result;
+      // Another tab bumping DB_VERSION needs every older connection gone
+      // before its upgrade can run; close ours instead of blocking it.
+      db.onversionchange = () => db.close();
+      resolve(db);
+    };
     request.onerror = () => reject(request.error);
+    // Without this the open request never settles while an older tab keeps
+    // the previous version open, and every caller (attachment upload, plugin
+    // loading) hangs silently. (#840)
+    request.onblocked = () =>
+      reject(
+        new Error(
+          'Plugin storage database is blocked by another open tab. Close other Bulwark tabs and try again.',
+        ),
+      );
   });
 }
 
@@ -42,8 +57,14 @@ async function putItem(storeName: string, key: string, value: string | Blob | Fi
   return new Promise((resolve, reject) => {
     const tx = db.transaction(storeName, 'readwrite');
     tx.objectStore(storeName).put(value, key);
-    tx.oncomplete = () => resolve();
-    tx.onerror = () => reject(tx.error);
+    tx.oncomplete = () => {
+      db.close();
+      resolve();
+    };
+    tx.onerror = () => {
+      db.close();
+      reject(tx.error);
+    };
   });
 }
 
@@ -54,6 +75,8 @@ async function getItem<T = string>(storeName: string, key: string): Promise<T |
     const request = tx.objectStore(storeName).get(key);
     request.onsuccess = () => resolve(request.result ?? null);
     request.onerror = () => reject(request.error);
+    tx.oncomplete = () => db.close();
+    tx.onerror = () => db.close();
   });
 }
 
@@ -62,8 +85,14 @@ async function deleteItem(storeName: string, key: string): Promise<void> {
   return new Promise((resolve, reject) => {
     const tx = db.transaction(storeName, 'readwrite');
     tx.objectStore(storeName).delete(key);
-    tx.oncomplete = () => resolve();
-    tx.onerror = () => reject(tx.error);
+    tx.oncomplete = () => {
+      db.close();
+      resolve();
+    };
+    tx.onerror = () => {
+      db.close();
+      reject(tx.error);
+    };
   });
 }