fix(mentions): ignore @everyone and @here in one-to-one DMs (#3199)

fluxer_api/src/api/channel/services/message/MessageMentionService.ts

@@ -90,6 +90,10 @@ export class MessageMentionService {
 		const roleMentions = allMentions.roles;
 		const channelMentions = allMentions.channels;
 		const isDMChannel = channelType === ChannelTypes.DM || channelType === ChannelTypes.DM_PERSONAL_NOTES;
+		if (isDMChannel) {
+			mentionsEveryone = false;
+			mentionsHere = false;
+		}
 		const shouldAddReferencedUser =
 			referencedMessage?.authorId &&
 			referencedMessage.authorId !== message.authorId &&

fluxer_api/src/api/channel/tests/DMEveryoneMention.test.ts

@@ -0,0 +1,44 @@
+// SPDX-License-Identifier: AGPL-3.0-or-later
+
+import {createTestAccount} from '@app/api/auth/tests/AuthTestUtils';
+import {
+	createDmChannel,
+	createFriendship,
+	createGroupDmChannel,
+	sendChannelMessage,
+} from '@app/api/channel/tests/ChannelTestUtils';
+import {type ApiTestHarness, createApiTestHarness} from '@app/api/test/ApiTestHarness';
+import {afterAll, beforeAll, beforeEach, describe, expect, it} from 'vitest';
+
+describe('DM everyone mention', () => {
+	let harness: ApiTestHarness;
+	beforeAll(async () => {
+		harness = await createApiTestHarness();
+	});
+	beforeEach(async () => {
+		await harness.reset();
+	});
+	afterAll(async () => {
+		await harness?.shutdown();
+	});
+	it('does not mention everyone in a one-to-one DM', async () => {
+		const user1 = await createTestAccount(harness);
+		const user2 = await createTestAccount(harness);
+		await createFriendship(harness, user1, user2);
+		const dm = await createDmChannel(harness, user1.token, user2.userId);
+		const everyone = await sendChannelMessage(harness, user1.token, dm.id, '@everyone test');
+		const here = await sendChannelMessage(harness, user1.token, dm.id, '@here test');
+		expect(everyone.mention_everyone).toBe(false);
+		expect(here.mention_everyone).toBe(false);
+	});
+	it('still mentions everyone in a group DM', async () => {
+		const user1 = await createTestAccount(harness);
+		const user2 = await createTestAccount(harness);
+		const user3 = await createTestAccount(harness);
+		await createFriendship(harness, user1, user2);
+		await createFriendship(harness, user1, user3);
+		const groupDm = await createGroupDmChannel(harness, user1.token, [user2.userId, user3.userId]);
+		const message = await sendChannelMessage(harness, user1.token, groupDm.id, '@everyone test');
+		expect(message.mention_everyone).toBe(true);
+	});
+});