do not notify if the target is not following

packages/backend/src/services/note/reaction/create.ts

@@ -12,6 +12,7 @@ import {
 	Notes,
 	Emojis,
 	Blockings,
+	Followings,
 } from "@/models/index.js";
 import { IsNull, Not } from "typeorm";
 import { perUserReactionsChart } from "@/services/chart/index.js";
@@ -21,6 +22,7 @@ import deleteReaction from "./delete.js";
 import { isDuplicateKeyValueError } from "@/misc/is-duplicate-key-value-error.js";
 import type { NoteReaction } from "@/models/entities/note-reaction.js";
 import { IdentifiableError } from "@/misc/identifiable-error.js";
+import { shouldSilenceInstance } from "@/misc/should-block-instance.js";
 
 export default async (
 	user: { id: User["id"]; host: User["host"] },
@@ -118,8 +120,25 @@ export default async (
 		userId: user.id,
 	});
 
-	// リアクションされたユーザーがローカルユーザーなら通知を作成
+	// Create notification if the reaction target is a local user.
-	if (note.userHost === null) {
+	if (
+		note.userHost === null &&
+		// if a local user reacted, or
+		(Users.isLocalUser(user) ||
+			// if a remote user not in a silenced instance reacted
+			(Users.isRemoteUser(user) &&
+			// if a remote user is in a silenced instance and the target is a local follower.
+				!(
+					(await shouldSilenceInstance(user.host)) &&
+					!(await Followings.exist({
+						where: {
+							followerId: note.userId,
+							followerHost: IsNull(),
+							followeeId: user.id,
+						},
+					}))
+				)))
+	) {
 		createNotification(note.userId, "reaction", {
 			notifierId: user.id,
 			note: note,
@@ -143,7 +162,7 @@ export default async (
 		}
 	});
 
-	//#region 配信
+	//#region deliver
 	if (Users.isLocalUser(user) && !note.localOnly) {
 		const content = renderActivity(await renderLike(record, note));
 		const dm = new DeliverManager(user, content);