FEATURE: Create revision when bulk moving topics (#10802)

This behavior can be configured with the new "create_revision_on_bulk_topic_moves" site setting. It's enabled by default.

lib/topics_bulk_action.rb

@@ -86,9 +86,26 @@ class TopicsBulkAction
   end
 
   def change_category
-    topics.each do |t|
-      if guardian.can_edit?(t)
-        @changed_ids << t.id if t.change_category_to_id(@operation[:category_id])
+    updatable_topics = topics.where.not(category_id: @operation[:category_id])
+
+    if SiteSetting.create_revision_on_bulk_topic_moves
+      opts = {
+        bypass_bump: true,
+        validate_post: false,
+        bypass_rate_limiter: true
+      }
+
+      updatable_topics.each do |t|
+        if guardian.can_edit?(t)
+          changes = { category_id: @operation[:category_id] }
+          @changed_ids << t.id if t.first_post.revise(@user, changes, opts)
+        end
+      end
+    else
+      updatable_topics.each do |t|
+        if guardian.can_edit?(t)
+          @changed_ids << t.id if t.change_category_to_id(@operation[:category_id])
+        end
       end
     end
   end