fix(unified-inbox): don't discard every account's envelopes if one account fails

src/store/mainStore/actions.js

@@ -722,13 +722,22 @@ export default function mainStoreActions() {
 				const mailbox = this.getMailbox(mailboxId)
 
 				if (mailbox.isUnified) {
+					// One account's fetch rejecting must not discard every
+					// other account's already-successful envelopes. Promise.all()
+					// rejects as soon as any single promise rejects, so a single
+					// slow/unreachable account used to make the whole unified
+					// mailbox render nothing at all instead of everything except
+					// that one account. See #9072.
 					const fetchIndividualLists = pipe(
 						map((mb) => this.fetchEnvelopes({
 							mailboxId: mb.databaseId,
 							query,
 							addToUnifiedMailboxes: false,
 							sort: this.getPreference('sort-order'),
 							view: this.getPreference('layout-message-view'),
+						}).catch((error) => {
+							logger.error(`Failed to fetch envelopes for unified constituent mailbox ${mb.databaseId}: ${error}`, { error })
+							return []
 						})),
 						Promise.all.bind(Promise),
 						andThen(map(sliceToPage)),
@@ -825,12 +834,18 @@ export default function mainStoreActions() {
 						logger.debug('not enough local envelopes for the next unified page. ' + mbs.length + ' fetches required', {
 							mailboxes: mbs.map((mb) => mb.databaseId),
 						})
+						// Same reasoning as fetchEnvelopes() above: one account
+						// failing must not fail pagination for every other
+						// account sharing this unified mailbox.
 						return pipe(
 							map((mb) => this.fetchNextEnvelopes({
 								mailboxId: mb.databaseId,
 								query,
 								quantity,
 								addToUnifiedMailboxes: false,
+							}).catch((error) => {
+								logger.error(`Failed to fetch next envelopes for unified constituent mailbox ${mb.databaseId}: ${error}`, { error })
+								return []
 							})),
 							Promise.all.bind(Promise),
 							andThen(() => this.fetchNextEnvelopes({

src/tests/unit/store/actions.spec.js

@@ -197,6 +197,73 @@ describe('Vuex store actions', () => {
 		})
 	})
 
+	it('creates a unified page from the accounts that succeed even if another account fails', async () => {
+		const account13 = {
+			id: 13,
+			personalNamespace: '',
+			mailboxes: [],
+		}
+		const account14 = {
+			id: 14,
+			personalNamespace: '',
+			mailboxes: [],
+		}
+
+		store.addAccountMutation(account13)
+		store.addAccountMutation(account14)
+		store.addMailboxMutation({
+			account: account13,
+			mailbox: {
+				id: 'INBOX',
+				name: 'INBOX',
+				databaseId: 21,
+				accountId: 13,
+				specialRole: 'inbox',
+			},
+		})
+		store.addMailboxMutation({
+			account: account14,
+			mailbox: {
+				id: 'INBOX',
+				name: 'INBOX',
+				databaseId: 31,
+				accountId: 14,
+				specialRole: 'inbox',
+			},
+		})
+
+		store.addEnvelopesMutation = vi.fn()
+
+		MessageService.fetchEnvelopes.mockImplementation(async (accountId) => {
+			if (accountId === 14) {
+				throw new Error('account 14 is temporarily unavailable')
+			}
+
+			return [{
+				databaseId: 123,
+				mailboxId: 21,
+				uid: 321,
+				subject: 'msg1',
+			}]
+		})
+
+		const envelopes = await store.fetchEnvelopes({
+			mailboxId: UNIFIED_INBOX_ID,
+		})
+
+		// The unreachable account (14) contributes nothing, but the
+		// reachable one (13) still renders instead of the whole unified
+		// fetch coming back empty.
+		expect(envelopes).toEqual([
+			{
+				databaseId: 123,
+				mailboxId: 21,
+				uid: 321,
+				subject: 'msg1',
+			},
+		])
+	})
+
 	it('fetches the next individual page', async () => {
 		const msgs1 = reverse(range(30, 40))
 		const page1 = reverse(range(10, 30))