FIX: Consider all eligible notification types when notifying about a post (#36472)

app/services/post_alerter.rb

@@ -338,11 +338,14 @@ class PostAlerter
     users = users.where.not(id: notified.map(&:id)) if notified.present?
 
     DiscourseEvent.trigger(:before_create_notifications_for_users, users, post)
+    received_notifications = []
     each_user_in_batches(users) do |user|
-      create_notification(user, Notification.types[:watching_first_post], post)
+      if create_notification(user, Notification.types[:watching_first_post], post).present?
+        received_notifications << user
+      end
     end
 
-    users
+    received_notifications
   end
 
   def sync_group_mentions(post, mentioned_groups)
@@ -798,9 +801,7 @@ class PostAlerter
     warn_if_not_sidekiq
 
     DiscourseEvent.trigger(:before_create_notifications_for_users, users, post)
-    users.each { |u| create_notification(u, Notification.types[type], post, opts) }
-
-    users
+    users.select { |u| create_notification(u, Notification.types[type], post, opts).present? }
   end
 
   def pm_watching_users(post)
@@ -843,7 +844,7 @@ class PostAlerter
     # flow will not be sent via group SMTP if it is enabled.
     users = indirectly_targeted_users(post).reject { |u| notified.include?(u) }
     DiscourseEvent.trigger(:before_create_notifications_for_users, users, post)
-    users.each do |user|
+    users.select do |user|
       case TopicUser.get(post.topic, user)&.notification_level
       when TopicUser.notification_levels[:watching]
         create_pm_notification(user, post, emails_to_skip_send)
@@ -1044,6 +1045,7 @@ class PostAlerter
           .pluck(:user_id),
       )
 
+    received_notifications = []
     each_user_in_batches(notify) do |user|
       calculated_type =
         if !new_record && already_seen_user_ids.include?(user.id)
@@ -1056,10 +1058,12 @@ class PostAlerter
       opts = {}
       opts[:display_username] = post.last_editor.username if calculated_type ==
         Notification.types[:edited]
-      create_notification(user, calculated_type, post, opts)
+      if create_notification(user, calculated_type, post, opts).present?
+        received_notifications << user
+      end
     end
 
-    notify
+    received_notifications
   end
 
   def warn_if_not_sidekiq

spec/services/post_alerter_spec.rb

@@ -1931,6 +1931,26 @@ RSpec.describe PostAlerter do
         ).and not_add_notification(staged_non_member, :watching_category_or_tag)
       end
 
+      it "notifies even if the user has disabled link notifications" do
+        linked_post = Fabricate(:post, user: user)
+        topic = Fabricate(:topic, category: category)
+
+        CategoryUser.set_notification_level_for_category(
+          user,
+          CategoryUser.notification_levels[:watching],
+          category.id,
+        )
+        user.user_option.update!(notify_on_linked_posts: false)
+
+        post = create_post(topic:, raw: "Check this out: #{linked_post.full_url}")
+
+        expect(post.topic_links.first.link_post_id).to eq(linked_post.id)
+        expect { PostAlerter.post_created(post) }.to add_notification(
+          user,
+          :watching_category_or_tag,
+        ).and not_add_notification(user, :linked)
+      end
+
       it "does not update existing unread notification" do
         CategoryUser.set_notification_level_for_category(
           user,
@@ -2034,6 +2054,23 @@ RSpec.describe PostAlerter do
 
         expect { PostAlerter.post_created(post) }.to change { Notification.count }.by(1)
       end
+
+      it "notifies even if the user has disabled link notifications" do
+        linked_post = Fabricate(:post, user: user)
+        tag = Fabricate(:tag)
+        topic = Fabricate(:topic, tags: [tag])
+
+        TagUser.change(user.id, tag.id, TagUser.notification_levels[:watching])
+        user.user_option.update!(notify_on_linked_posts: false)
+
+        post = create_post(topic:, raw: "Check this out: #{linked_post.full_url}")
+
+        expect(post.topic_links.first.link_post_id).to eq(linked_post.id)
+        expect { PostAlerter.post_created(post) }.to add_notification(
+          user,
+          :watching_category_or_tag,
+        ).and not_add_notification(user, :linked)
+      end
     end
 
     context "with category and tags" do