Allow changes of post owner on unpublished local topics (#109)

extensions/discourse_activity_pub_guardian_extension.rb

@@ -10,14 +10,14 @@ def can_edit_post?(post)
   end
 
   def can_change_post_owner?
-    return false if activity_pub_enabled_topic?
+    return false if activity_pub_change_owner_restricted?
     super
   end
 
-  def activity_pub_enabled_topic?
+  def activity_pub_change_owner_restricted?
     return false unless DiscourseActivityPub.enabled && request&.params&.[]("topic_id")
     topic = Topic.find_by(id: request.params["topic_id"].to_i)
-    topic&.activity_pub_enabled
+    topic && (topic.activity_pub_remote? || topic.activity_pub_published?)
   end
 
   def can_admin?(actor)

plugin.rb

@@ -265,7 +265,10 @@
   add_to_class(:topic, :activity_pub_objects_collection) { activity_pub_object.objects_collection }
   add_to_class(:topic, :activity_pub_actor) { activity_pub_taxonomy&.activity_pub_actor }
   add_to_class(:topic, :activity_pub_name) { title }
-
+  add_to_class(:topic, :activity_pub_local?) do
+    !first_post&.activity_pub_object || first_post.activity_pub_object.local
+  end
+  add_to_class(:topic, :activity_pub_remote?) { !activity_pub_local? }
   Post.has_one :activity_pub_object, class_name: "DiscourseActivityPubObject", as: :model
 
   Post.include DiscourseActivityPub::AP::ModelCallbacks

spec/lib/guardian_spec.rb

@@ -52,6 +52,22 @@
   end
 
   describe "can_change_post_owner?" do
+    shared_examples "returns true for admins" do
+      it "returns true for admins" do
+        expect(Guardian.new(admin, request).can_change_post_owner?).to be_truthy
+        expect(Guardian.new(user, request).can_change_post_owner?).to be_falsey
+        expect(Guardian.new(another_user, request).can_change_post_owner?).to be_falsey
+      end
+    end
+
+    shared_examples "returns false for all users" do
+      it "returns false for all users" do
+        expect(Guardian.new(admin, request).can_change_post_owner?).to be_falsey
+        expect(Guardian.new(user, request).can_change_post_owner?).to be_falsey
+        expect(Guardian.new(another_user, request).can_change_post_owner?).to be_falsey
+      end
+    end
+
     describe "a Post" do
       context "with a change owner request" do
         let!(:request) do
@@ -74,19 +90,30 @@
         context "with activity pub enabled" do
           before { toggle_activity_pub(category) }
 
-          it "returns false for all users" do
-            expect(Guardian.new(admin, request).can_change_post_owner?).to be_falsey
-            expect(Guardian.new(user, request).can_change_post_owner?).to be_falsey
-            expect(Guardian.new(another_user, request).can_change_post_owner?).to be_falsey
+          context "when the topic is not published" do
+            include_examples "returns true for admins"
+          end
+
+          context "when the topic is published" do
+            before do
+              post.custom_fields["activity_pub_published_at"] = Time.now
+              post.save_custom_fields(true)
+            end
+
+            include_examples "returns false for all users"
+          end
+
+          context "when the topic is remote" do
+            fab!(:note) do
+              Fabricate(:discourse_activity_pub_object_note, model: post, local: false)
+            end
+
+            include_examples "returns false for all users"
           end
         end
 
         context "with activity pub disabled" do
-          it "returns true for the right users" do
-            expect(Guardian.new(admin, request).can_change_post_owner?).to be_truthy
-            expect(Guardian.new(user, request).can_change_post_owner?).to be_falsey
-            expect(Guardian.new(another_user, request).can_change_post_owner?).to be_falsey
-          end
+          include_examples "returns true for admins"
         end
       end
     end