FEATURE: Deleting a user with their posts also deletes chat messages. (#19194)

This commit introduce a new API for registering callbacks, which we'll execute when a user gets destroyed, and the `delete_posts` opt is true. The chat plugin registers one callback and queues a job to destroy every message from that user in batches.

plugins/chat/spec/jobs/delete_old_chat_messages_spec.rb

@@ -109,40 +109,6 @@ describe Jobs::DeleteOldChatMessages do
       SiteSetting.chat_channel_retention_days = 800
       expect { described_class.new.execute }.not_to change { ChatMessage.in_public_channel.count }
     end
-
-    it "resets last_read_message_id from memberships" do
-      SiteSetting.chat_channel_retention_days = 20
-      membership =
-        UserChatChannelMembership.create!(
-          user: Fabricate(:user),
-          chat_channel: public_channel,
-          last_read_message_id: public_days_old_30.id,
-          following: true,
-          desktop_notification_level: 2,
-          mobile_notification_level: 2,
-        )
-      described_class.new.execute
-
-      expect(membership.reload.last_read_message_id).to be_nil
-    end
-
-    it "deletes flags associated to deleted chat messages" do
-      SiteSetting.chat_channel_retention_days = 10
-      guardian = Guardian.new(Discourse.system_user)
-      Chat::ChatReviewQueue.new.flag_message(
-        public_days_old_20,
-        guardian,
-        ReviewableScore.types[:off_topic],
-      )
-
-      reviewable = ReviewableChatMessage.last
-      expect(reviewable).to be_present
-
-      described_class.new.execute
-
-      expect { public_days_old_20.reload }.to raise_exception(ActiveRecord::RecordNotFound)
-      expect { reviewable.reload }.to raise_exception(ActiveRecord::RecordNotFound)
-    end
   end
 
   describe "dm channels" do
@@ -166,21 +132,5 @@ describe Jobs::DeleteOldChatMessages do
       SiteSetting.chat_dm_retention_days = 800
       expect { described_class.new.execute }.not_to change { ChatMessage.in_dm_channel.count }
     end
-
-    it "resets last_read_message_id from memberships" do
-      SiteSetting.chat_dm_retention_days = 20
-      membership =
-        UserChatChannelMembership.create!(
-          user: Fabricate(:user),
-          chat_channel: dm_channel,
-          last_read_message_id: dm_days_old_30.id,
-          following: true,
-          desktop_notification_level: 2,
-          mobile_notification_level: 2,
-        )
-      described_class.new.execute
-
-      expect(membership.reload.last_read_message_id).to be_nil
-    end
   end
 end

plugins/chat/spec/jobs/regular/delete_user_messages_spec.rb

@@ -0,0 +1,32 @@
+# frozen_string_literal: true
+
+RSpec.describe Jobs::DeleteUserMessages do
+  describe "#execute" do
+    fab!(:user_1) { Fabricate(:user) }
+    fab!(:channel) { Fabricate(:chat_channel) }
+    fab!(:chat_message) { Fabricate(:chat_message, chat_channel: channel, user: user_1) }
+
+    it "deletes messages from the user" do
+      subject.execute(user_id: user_1)
+
+      expect { chat_message.reload }.to raise_error(ActiveRecord::RecordNotFound)
+    end
+
+    it "doesn't delete messages from other users" do
+      user_2 = Fabricate(:user)
+      user_2_message = Fabricate(:chat_message, chat_channel: channel, user: user_2)
+
+      subject.execute(user_id: user_1)
+
+      expect(user_2_message.reload).to be_present
+    end
+
+    it "deletes trashed messages" do
+      chat_message.trash!
+
+      subject.execute(user_id: user_1)
+
+      expect(ChatMessage.with_deleted.where(id: chat_message.id)).to be_empty
+    end
+  end
+end