DEV: add full_move to MovedPost record small_action modifier (#30236)

This commit adds a new column full_move to the moved_posts table. This is useful to look back at history and determine if a whole topic was moved or partial.

This commit also adds an apply_modifier to skip the creation of the moved posts small action.

app/models/moved_post.rb

@@ -32,6 +32,7 @@ end
 #  old_topic_title   :string
 #  post_user_id      :integer
 #  user_id           :integer
+#  full_move         :boolean
 #
 # Indexes
 #

app/models/post_mover.rb

@@ -92,14 +92,14 @@ class PostMover
           Post.types[:whisper],
         )
         .count
-    moving_all_posts = original_topic_posts_count == posts.length
+    @full_move = original_topic_posts_count == posts.length
 
     @first_post_number_moved =
       posts.first.is_first_post? ? posts[1]&.post_number : posts.first.post_number
 
     if @options[:freeze_original] # in this case we need to add the moderator post after the last copied post
       from_posts = @original_topic.ordered_posts.where("post_number > ?", posts.last.post_number)
-      shift_post_numbers(from_posts) if !moving_all_posts
+      shift_post_numbers(from_posts) if !@full_move
 
       @first_post_number_moved = posts.last.post_number + 1
     end
@@ -114,7 +114,7 @@ class PostMover
     update_upload_security_status
     update_bookmarks
 
-    close_topic_and_schedule_deletion if moving_all_posts
+    close_topic_and_schedule_deletion if @full_move
 
     destination_topic.reload
     DiscourseEvent.trigger(
@@ -366,10 +366,11 @@ class PostMover
     metadata[:created_new_topic] = @creating_new_topic
     metadata[:old_topic_title] = @original_topic_title
     metadata[:user_id] = @user.id
+    metadata[:full_move] = @full_move
 
     DB.exec(<<~SQL, metadata)
-      INSERT INTO moved_posts(old_topic_id, old_topic_title, old_post_id, old_post_number, post_user_id, user_id, new_topic_id, new_topic_title, new_post_id, new_post_number, created_new_topic, created_at, updated_at)
+      INSERT INTO moved_posts(old_topic_id, old_topic_title, old_post_id, old_post_number, post_user_id, user_id, full_move, new_topic_id, new_topic_title, new_post_id, new_post_number, created_new_topic, created_at, updated_at)
-      VALUES (:old_topic_id, :old_topic_title, :old_post_id, :old_post_number, :post_user_id, :user_id, :new_topic_id, :new_topic_title, :new_post_id, :new_post_number, :created_new_topic, :now, :now)
+      VALUES (:old_topic_id, :old_topic_title, :old_post_id, :old_post_number, :post_user_id, :user_id, :full_move, :new_topic_id, :new_topic_title, :new_post_id, :new_post_number, :created_new_topic, :now, :now)
     SQL
   end
 
@@ -613,23 +614,38 @@ class PostMover
     move_type_str = PostMover.move_types[@move_type].to_s
     move_type_str.sub!("topic", "message") if @move_to_pm
 
+    topic_link =
+      if posts.first.is_first_post?
+        "[#{destination_topic.title}](#{destination_topic.relative_url})"
+      else
+        "[#{destination_topic.title}](#{posts.first.relative_url})"
+      end
+
+    post_type = @move_to_pm ? Post.types[:whisper] : Post.types[:small_action]
+
+    continue =
+      DiscoursePluginRegistry.apply_modifier(
+        :post_mover_create_moderator_post,
+        true,
+        user: user,
+        post_type: post_type,
+        post_ids: @post_ids_after_move,
+        full_move: @full_move,
+        original_topic: original_topic,
+        destination_topic: destination_topic,
+        first_post_number_moved: @first_post_number_moved,
+      )
+    return if !continue
+
     message =
       I18n.with_locale(SiteSetting.default_locale) do
         I18n.t(
           "move_posts.#{move_type_str}_moderator_post",
           count: posts.length,
-          topic_link:
+          topic_link: topic_link,
-            (
-              if posts.first.is_first_post?
-                "[#{destination_topic.title}](#{destination_topic.relative_url})"
-              else
-                "[#{destination_topic.title}](#{posts.first.relative_url})"
-              end
-            ),
         )
       end
 
-    post_type = @move_to_pm ? Post.types[:whisper] : Post.types[:small_action]
     original_topic.add_moderator_post(
       user,
       message,

db/migrate/20241211222608_add_full_move_to_moved_post_records.rb

@@ -0,0 +1,7 @@
+# frozen_string_literal: true
+
+class AddFullMoveToMovedPostRecords < ActiveRecord::Migration[7.2]
+  def change
+    add_column :moved_posts, :full_move, :boolean
+  end
+end

spec/models/post_mover_spec.rb

@@ -351,6 +351,42 @@ RSpec.describe PostMover do
             expect(topic.closed).to eq(true)
           end
 
+          it "records full_move=true in MovedPost records when all posts are moved" do
+            post_ids = [p1.id, p2.id, p3.id, p4.id]
+            new_topic =
+              topic.move_posts(
+                user,
+                [p1.id, p2.id, p3.id, p4.id],
+                title: "new testing topic name",
+                category_id: category.id,
+              )
+            expect(
+              MovedPost.where(
+                old_post_id: post_ids,
+                new_topic_id: new_topic.id,
+                full_move: true,
+              ).count,
+            ).to eq(4)
+          end
+
+          it "records full_move=false in MovedPost records when only some posts" do
+            post_ids = [p3.id, p4.id]
+            new_topic =
+              topic.move_posts(
+                user,
+                [p3.id, p4.id],
+                title: "new testing topic name",
+                category_id: category.id,
+              )
+            expect(
+              MovedPost.where(
+                old_post_id: post_ids,
+                new_topic_id: new_topic.id,
+                full_move: false,
+              ).count,
+            ).to eq(2)
+          end
+
           it "does not move posts that do not belong to the existing topic" do
             new_topic =
               topic.move_posts(user, [p2.id, p3.id, p5.id], title: "Logan is a pretty good movie")
@@ -2854,6 +2890,43 @@ RSpec.describe PostMover do
         expect(moderator_post.action_code).to eq("split_topic")
       end
 
+      context "with `post_mover_create_moderator_post` modifier" do
+        fab!(:topic_1) { Fabricate(:topic) }
+        fab!(:topic_2) { Fabricate(:topic) }
+        fab!(:post_1) { Fabricate(:post, topic: topic_1) }
+        fab!(:user)
+
+        before { SiteSetting.delete_merged_stub_topics_after_days = 0 }
+        let(:modifier_block) { Proc.new { |continue, _| false } }
+
+        it "does not create small action post when modifier returns false" do
+          plugin_instance = Plugin::Instance.new
+          plugin_instance.register_modifier(:post_mover_create_moderator_post, &modifier_block)
+
+          expect {
+            PostMover.new(
+              original_topic,
+              Discourse.system_user,
+              [first_post.id, second_post.id],
+              options: {
+                freeze_original: true,
+              },
+            ).to_topic(destination_topic.id)
+          }.not_to change {
+            original_topic
+              .posts
+              .where(post_type: Post.types[:small_action], action_code: "split_topic")
+              .count
+          }
+        ensure
+          DiscoursePluginRegistry.unregister_modifier(
+            plugin_instance,
+            :post_mover_create_moderator_post,
+            &modifier_block
+          )
+        end
+      end
+
       it "keeps posts when moving all posts to a new topic" do
         all_posts_from_original_topic = original_topic.ordered_posts.map(&:raw)