fix: only offer archiving when the archive folder can take the mail #578

The list resolved the Archive folder with a loose name match ("Archives",
"Archived" or any name containing "archive"), while the store's archive
actions only accept the `archive` role or a folder named exactly
"Archive". With a role-less "Archives" folder the swipe and bulk archive
were offered but silently did nothing.

`findArchiveMailbox` now uses the webmail's rules (role first, then the
exact name, case-insensitive) and both store archive actions resolve
through it, so the list offers archiving only when it will run and
otherwise shows the existing "no Archive folder" message.

src/lib/__tests__/mailbox-tree.test.ts

@@ -1,6 +1,7 @@
 import { describe, it, expect } from 'vitest';
 import {
   buildMailboxTree,
+  findArchiveMailbox,
   flattenVisible,
   mailboxAccountId,
   mailboxesForSiblingOf,
@@ -205,3 +206,28 @@ describe('role-folder deduplication (#771)', () => {
     expect(tree.find((n) => n.id === 'proj')?.children.map((n) => n.id)).toEqual(['proj-sent']);
   });
 });
+
+describe('findArchiveMailbox (#578)', () => {
+  it('prefers the archive role over a folder named Archive', () => {
+    const found = findArchiveMailbox([
+      own('named', 'Archive'),
+      own('role', 'Old mail', { role: 'archive' }),
+    ]);
+    expect(found?.id).toBe('role');
+  });
+
+  it('falls back to a role-less folder named exactly "Archive", any case', () => {
+    expect(findArchiveMailbox([own('inbox', 'Inbox', { role: 'inbox' }), own('a', 'ARCHIVE')])?.id)
+      .toBe('a');
+  });
+
+  it('does not treat "Archives" or folders merely containing "archive" as the Archive', () => {
+    // The store's archive actions only file into a folder this resolver
+    // returns; a looser match here offered an archive that did nothing.
+    expect(findArchiveMailbox([
+      own('plural', 'Archives'),
+      own('past', 'Archived'),
+      own('proj', 'Project archive 2019'),
+    ])).toBeUndefined();
+  });
+});

src/lib/mailbox-tree.ts

@@ -272,15 +272,16 @@ export function findTrashMailbox(mailboxes: Mailbox[]): Mailbox | undefined {
   });
 }
 
+/**
+ * The Archive folder: the `archive` role, else a role-less folder named
+ * exactly "Archive" (any case), as the webmail matches it. Whatever offers
+ * the archive action must resolve through this, like the store's archive
+ * actions do: a looser list-only match used to offer archiving into e.g.
+ * "Archives", which the store then silently ignored. (#578)
+ */
 export function findArchiveMailbox(mailboxes: Mailbox[]): Mailbox | undefined {
-  const roleMatch = mailboxes.find((m) => m.role === 'archive');
-  if (roleMatch) return roleMatch;
-
-  const names = ['archive', 'archives', 'archived'];
-  return mailboxes.find((m) => {
-    const lower = m.name.toLowerCase();
-    return names.includes(lower) || names.some((n) => lower.includes(n));
-  });
+  return mailboxes.find((m) => m.role === 'archive')
+    ?? mailboxes.find((m) => m.name.toLowerCase() === 'archive');
 }
 
 export function findJunkMailbox(mailboxes: Mailbox[]): Mailbox | undefined {

src/stores/email-store.ts

@@ -34,7 +34,7 @@ import {
 } from '../api/email';
 import { useNetworkStore } from './network-store';
 import { JMAPMethodError } from '../api/jmap-result';
-import { mailboxesForSiblingOf, mailboxesOfAccount, findJunkMailbox } from '../lib/mailbox-tree';
+import { mailboxesForSiblingOf, mailboxesOfAccount, findJunkMailbox, findArchiveMailbox } from '../lib/mailbox-tree';
 import { toWildcardQuery } from '../lib/search-utils';
 import { orderForMailbox, sanitizeSortLevels, type SortLevel } from '../lib/message-list-order';
 import { buildListSort, markKeywordSortUnsupported } from '../lib/keyword-sort-polarity';
@@ -1251,9 +1251,7 @@ export const useEmailStore = create<EmailState>()(
     // Archive into the *same account's* Archive folder — a shared mailbox's
     // messages can't be filed into the user's own.
     const scoped = actionMailboxes(state, viewed);
-    const archiveMailbox = scoped.find(
-      (m) => m.role === 'archive' || m.name.toLowerCase() === 'archive',
-    );
+    const archiveMailbox = findArchiveMailbox(scoped);
     if (!archiveMailbox) return;
     const archive = refFor(state.mailboxes, archiveMailbox.id);
     if (email.mailboxIds?.[archive.id]) return;
@@ -1379,9 +1377,7 @@ export const useEmailStore = create<EmailState>()(
   archiveEmailsBatch: async (emailIds) => {
     const state = get();
     const scoped = mailboxesForSiblingOf(state.mailboxes, state.currentMailboxId);
-    const archiveMailbox = scoped.find(
-      (m) => m.role === 'archive' || m.name.toLowerCase() === 'archive',
-    );
+    const archiveMailbox = findArchiveMailbox(scoped);
     if (!archiveMailbox) return;
     const archive = refFor(state.mailboxes, archiveMailbox.id);
     const targets = state.emails.filter(