From 2b186910d5f6d0437403add932effc233b1b0dfd 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: subscribe newly created mailboxes #951

---
 lib/__tests__/jmap-mailbox-account.test.ts | 2 +-
 lib/jmap/client.ts                         | 5 ++++-
 2 files changed, 5 insertions(+), 2 deletions(-)

diff --git a/lib/__tests__/jmap-mailbox-account.test.ts b/lib/__tests__/jmap-mailbox-account.test.ts
index ca667edf4..39fc3a130 100644
--- a/lib/__tests__/jmap-mailbox-account.test.ts
+++ b/lib/__tests__/jmap-mailbox-account.test.ts
@@ -56,7 +56,7 @@ describe('JMAP mailbox mutations use the requested account', () => {
     expect(captured[0][0]).toBe('Mailbox/set');
     expect(captured[0][1].accountId).toBe('shared-account');
     expect(Object.values(captured[0][1].create as Record<string, unknown>))
-      .toEqual([{ name: 'Child', parentId: 'parent-id' }]);
+      .toEqual([{ name: 'Child', parentId: 'parent-id', isSubscribed: true }]);
     expect(mailbox).toMatchObject({
       id: 'created-mailbox',
       accountId: 'shared-account',
diff --git a/lib/jmap/client.ts b/lib/jmap/client.ts
index 6458e0163..ccb8d4b35 100644
--- a/lib/jmap/client.ts
+++ b/lib/jmap/client.ts
@@ -2691,7 +2691,10 @@ export class JMAPClient implements IJMAPClient {
   async createMailbox(name: string, parentId?: string, accountId?: string): Promise<Mailbox> {
     const targetAccountId = accountId || this.accountId;
     const createId = `new-${Date.now()}`;
-    const createData: Record<string, unknown> = { name };
+    // Subscribe explicitly: IMAP clients that list folders via LSUB
+    // (Thunderbird) hide unsubscribed mailboxes, and the server default is
+    // not guaranteed to be true. (#951)
+    const createData: Record<string, unknown> = { name, isSubscribed: true };
     if (parentId) {
       createData.parentId = parentId;
     }