fix: improve mailbox role management by ensuring roles are cleared from all mailboxes when reassigning

stores/__tests__/folder-management.test.ts

@@ -226,6 +226,34 @@ describe('email-store folder management', () => {
       expect(client.updateMailbox).toHaveBeenCalledWith('trash-1', { role: 'trash' });
     });
 
+    it('should clear role from ALL mailboxes with that role when reassigning', async () => {
+      // Simulate server anomaly: two mailboxes with role "trash"
+      const extraTrash = makeMailbox({ id: 'trash-2', name: 'Deleted Items', role: 'trash' });
+      useEmailStore.setState({
+        mailboxes: [inbox, sent, trash, custom, extraTrash],
+      });
+
+      const newMailboxes = [inbox, sent, custom,
+        makeMailbox({ id: 'trash-1', name: 'Trash', role: undefined }),
+        makeMailbox({ id: 'trash-2', name: 'Deleted Items', role: undefined }),
+      ];
+      // custom-1 gets the trash role
+      newMailboxes[2] = { ...newMailboxes[2], role: 'trash' };
+
+      const client = makeMockClient({
+        getAllMailboxes: vi.fn().mockResolvedValue(newMailboxes),
+      });
+
+      await useEmailStore.getState().setMailboxRole(client, 'custom-1', 'trash');
+
+      // Should clear trash role from BOTH trash-1 and trash-2
+      expect(client.updateMailbox).toHaveBeenCalledWith('trash-1', { role: null });
+      expect(client.updateMailbox).toHaveBeenCalledWith('trash-2', { role: null });
+      // Then set trash role on custom-1
+      expect(client.updateMailbox).toHaveBeenCalledWith('custom-1', { role: 'trash' });
+      expect(client.updateMailbox).toHaveBeenCalledTimes(3);
+    });
+
     it('should set error on failure', async () => {
       const client = makeMockClient({
         updateMailbox: vi.fn().mockRejectedValue(new Error('Role update failed')),

stores/email-store.ts

@@ -1298,11 +1298,11 @@ export const useEmailStore = create<EmailStore>((set, get) => ({
 
   setMailboxRole: async (client, mailboxId, role) => {
     try {
-      // If assigning a role, first clear that role from any other mailbox
+      // If assigning a role, first clear that role from ALL other mailboxes that have it
       if (role) {
-        const existingMailbox = get().mailboxes.find(mb => mb.role === role && !mb.isShared);
-        if (existingMailbox && existingMailbox.id !== mailboxId) {
-          await client.updateMailbox(existingMailbox.id, { role: null });
+        const existingMailboxes = get().mailboxes.filter(mb => mb.role === role && !mb.isShared && mb.id !== mailboxId);
+        for (const existing of existingMailboxes) {
+          await client.updateMailbox(existing.id, { role: null });
         }
       }
       await client.updateMailbox(mailboxId, { role });