FIX: Post moved small action links should respect subfolder installs (#24336)

This change fixes an issue with small action links (when post is moved) to add the subfolder path to the url.

app/models/post.rb

@@ -646,6 +646,10 @@ class Post < ActiveRecord::Base
     "#{Discourse.base_url}#{url}"
   end
 
+  def relative_url
+    "#{Discourse.base_path}#{url}"
+  end
+
   def url(opts = nil)
     opts ||= {}
 

app/models/post_mover.rb

@@ -591,7 +591,7 @@ class PostMover
               if posts.first.is_first_post?
                 "[#{destination_topic.title}](#{destination_topic.relative_url})"
               else
-                "[#{destination_topic.title}](#{posts.first.url})"
+                "[#{destination_topic.title}](#{posts.first.relative_url})"
               end
             ),
         )

spec/models/post_mover_spec.rb

@@ -887,6 +887,27 @@ RSpec.describe PostMover do
             expect(new_post.post_revisions.size).to eq(1)
           end
 
+          context "with subfolder installs" do
+            before { set_subfolder "/forum" }
+
+            it "creates a small action with correct post url" do
+              moved_to = topic.move_posts(user, [p2.id], destination_topic_id: destination_topic.id)
+              small_action = topic.posts.last
+
+              expect(small_action.post_type).to eq(Post.types[:small_action])
+
+              expected_text =
+                I18n.t(
+                  "move_posts.existing_topic_moderator_post",
+                  count: 1,
+                  topic_link: "[#{moved_to.title}](#{p2.reload.relative_url})",
+                  locale: :en,
+                )
+
+              expect(small_action.raw).to eq(expected_text)
+            end
+          end
+
           context "with read state and other stats per user" do
             def create_topic_user(user, topic, opts = {})
               notification_level = opts.delete(:notification_level) || :regular

spec/models/post_spec.rb

@@ -2135,6 +2135,17 @@ RSpec.describe Post do
     end
   end
 
+  describe "relative_url" do
+    it "returns the correct post url with subfolder install" do
+      set_subfolder "/forum"
+      post = Fabricate(:post)
+
+      expect(post.relative_url).to eq(
+        "/forum/t/#{post.topic.slug}/#{post.topic.id}/#{post.post_number}",
+      )
+    end
+  end
+
   describe "public_posts_count_per_day" do
     before do
       freeze_time DateTime.parse("2017-03-01 12:00")