FIX: Moderator notifications when new post auto-silences a user (#35403)

When a user is auto-silenced because they receive enough spam flag, we notify moderators (given the notify_mods_when_user_silenced is enabled).

However, when a user is auto-silenced for other reasons, e.g. typing too fast, we don't send this notification.

This commit:

- Lifts the notification logic into a new UserSilencer#auto_silence method, which delegates 99% of its work to UserSilencer#silence.
- Uses this new method in places where users are auto-silenced.

app/services/spam_rule/auto_silence.rb

@@ -57,24 +57,11 @@ class SpamRule::AutoSilence
   end
 
   def silence_user
-    Post.transaction do
-      silencer =
-        UserSilencer.new(
-          @user,
-          Discourse.system_user,
-          message: :too_many_spam_flags,
-          post_id: @post&.id,
-        )
-
-      if silencer.silence && SiteSetting.notify_mods_when_user_silenced
-        @group_message =
-          GroupMessage.create(
-            Group[:moderators].name,
-            :user_automatically_silenced,
-            user: @user,
-            limit_once_per: false,
-          )
-      end
-    end
+    UserSilencer.auto_silence(
+      @user,
+      Discourse.system_user,
+      message: :too_many_spam_flags,
+      post_id: @post&.id,
+    )
   end
 end

app/services/user_silencer.rb

@@ -11,6 +11,10 @@ class UserSilencer
     UserSilencer.new(user, by_user, opts).silence
   end
 
+  def self.auto_silence(user, by_user = nil, opts = {})
+    UserSilencer.new(user, by_user, opts).auto_silence
+  end
+
   def self.unsilence(user, by_user = nil, opts = {})
     UserSilencer.new(user, by_user, opts).unsilence
   end
@@ -59,6 +63,15 @@ class UserSilencer
     end
   end
 
+  def auto_silence
+    if silence
+      notify_moderators
+      true
+    else
+      false
+    end
+  end
+
   def hide_posts
     return unless @user.trust_level == TrustLevel[0]
 
@@ -87,4 +100,17 @@ class UserSilencer
       StaffActionLogger.new(@by_user).log_unsilence_user(@user) if @by_user
     end
   end
+
+  private
+
+  def notify_moderators
+    return if !SiteSetting.notify_mods_when_user_silenced
+
+    GroupMessage.create(
+      Group[:moderators].name,
+      :user_automatically_silenced,
+      user: @user,
+      limit_once_per: false,
+    )
+  end
 end

lib/new_post_manager.rb

@@ -178,21 +178,21 @@ class NewPostManager
 
     I18n.with_locale(SiteSetting.default_locale) do
       if is_fast_typer?(manager)
-        UserSilencer.silence(
+        UserSilencer.auto_silence(
           manager.user,
           Discourse.system_user,
           keep_posts: true,
           reason: I18n.t("user.new_user_typed_too_fast"),
         )
       elsif auto_silence?(manager) || matches_auto_silence_regex?(manager)
-        UserSilencer.silence(
+        UserSilencer.auto_silence(
           manager.user,
           Discourse.system_user,
           keep_posts: true,
           reason: I18n.t("user.content_matches_auto_silence_regex"),
         )
       elsif reason == :email_spam && is_first_post?(manager)
-        UserSilencer.silence(
+        UserSilencer.auto_silence(
           manager.user,
           Discourse.system_user,
           keep_posts: true,

spec/lib/new_post_manager_spec.rb

@@ -258,17 +258,23 @@ RSpec.describe NewPostManager do
     end
 
     context "with a fast typer" do
-      before { user.update!(trust_level: 0) }
+      before do
+        user.update!(trust_level: 0)
+        SiteSetting.notify_mods_when_user_silenced = true
+      end
 
       it "adds the silence reason in the system locale" do
         manager = build_manager_with("this is new post content")
 
         I18n.with_locale(:fr) do # Simulate french user
-          result = NewPostManager.default_handler(manager)
+          expect { NewPostManager.default_handler(manager) }.to change { user.silenced? }.to(
+            true,
+          ).and change { user.silence_reason }.to(
+                  I18n.t("user.new_user_typed_too_fast", locale: :en),
+                ).and change {
+                        Topic.where("subtype = 'system_message' AND title LIKE '%silenced%'").count
+                      }.by(1)
         end
-
-        expect(user.silenced?).to eq(true)
-        expect(user.silence_reason).to eq(I18n.t("user.new_user_typed_too_fast", locale: :en))
       end
 
       it "runs the watched words check before checking if the user is a fast typer" do
@@ -692,6 +698,8 @@ RSpec.describe NewPostManager do
     let(:user) { Fabricate(:user, refresh_auto_groups: true) }
     let(:admin) { Fabricate(:admin) }
 
+    before { SiteSetting.notify_mods_when_user_silenced = true }
+
     it "silences users if its their first post" do
       manager =
         NewPostManager.new(
@@ -703,9 +711,10 @@ RSpec.describe NewPostManager do
           first_post_checks: true,
         )
 
-      result = manager.perform
-      expect(result.action).to eq(:enqueued)
-      expect(user.silenced?).to be(true)
+      expect { @result = manager.perform }.to change { user.silenced? }.to(true).and change {
+              Topic.where("subtype = 'system_message' AND title LIKE '%silenced%'").count
+            }.by(1)
+      expect(@result.action).to eq(:enqueued)
     end
 
     it "doesn't silence or enqueue exempt users" do

spec/services/auto_silence_spec.rb

@@ -118,14 +118,16 @@ RSpec.describe SpamRule::AutoSilence do
 
         it "sends private message to moderators" do
           SiteSetting.notify_mods_when_user_silenced = true
-          autosilence.silence_user
-          expect(autosilence.group_message).to be_present
+          expect { autosilence.silence_user }.to change {
+            Topic.where("subtype = 'system_message' AND title LIKE '%silenced%'").count
+          }.by(1)
         end
 
         it "doesn't send a pm to moderators if notify_mods_when_user_silenced is false" do
           SiteSetting.notify_mods_when_user_silenced = false
-          autosilence.silence_user
-          expect(autosilence.group_message).to be_blank
+          expect { autosilence.silence_user }.not_to change {
+            Topic.where("subtype = 'system_message' AND title LIKE '%silenced%'").count
+          }
         end
       end
     end