FIX: Revise and reject post breaks on new topics queued (#24109)

Followup to 9762e65758. This
original commit did not take into account the fact that
new topics can end up in the approval queue as a
ReviewableQueuedPost, and so there was a 500 error raised
when accessing `self.topic` when sending a PM to the user.

app/models/reviewable_queued_post.rb

@@ -163,8 +163,8 @@ class ReviewableQueuedPost < Reviewable
 
   def perform_revise_and_reject_post(performed_by, args)
     pm_translation_args = {
-      topic_title: self.topic.title,
-      topic_url: self.topic.url,
+      topic_title: self.topic&.title || self.payload["title"],
+      topic_url: self.topic&.url,
       reason: args[:revise_custom_reason].presence || args[:revise_reason],
       feedback: args[:revise_feedback],
       original_post: self.payload["raw"],
@@ -172,7 +172,13 @@ class ReviewableQueuedPost < Reviewable
     }
     SystemMessage.create_from_system_user(
       self.target_created_by,
-      :reviewable_queued_post_revise_and_reject,
+      (
+        if self.topic.blank?
+          :reviewable_queued_post_revise_and_reject_new_topic
+        else
+          :reviewable_queued_post_revise_and_reject
+        end
+      ),
       pm_translation_args,
     )
     StaffActionLogger.new(performed_by).log_post_rejected(self, DateTime.now) if performed_by.staff?

config/locales/server.en.yml

@@ -3010,6 +3010,29 @@ en:
         Thanks,
         %{site_name} Moderators
 
+    reviewable_queued_post_revise_and_reject_new_topic:
+      title: "Feedback on your topic"
+      subject_template: "Feedback on new topic titled \"%{topic_title}\""
+      text_body_template: |
+        Hi %{username},
+
+        We've reviewed your new topic titled "%{topic_title}" and have some feedback for you.
+
+        Reason: %{reason}
+
+        Feedback: %{feedback}
+
+        You can edit your topic's original post below and re-submit to make the suggested changes, or reply to this message if you have any questions.
+
+        --------
+
+        %{original_post}
+
+        --------
+
+        Thanks,
+        %{site_name} Moderators
+
     post_hidden_again:
       title: "Post Hidden again"
       subject_template: "Post hidden by community flags, staff notified"

spec/models/reviewable_queued_post_spec.rb

@@ -178,6 +178,40 @@ RSpec.describe ReviewableQueuedPost, type: :model do
           expect(topic.first_post.raw).not_to include("Other...")
           expect(topic.first_post.raw).to include("Boring")
         end
+
+        context "when the topic is nil in the case of a new topic being created" do
+          let(:reviewable) { Fabricate(:reviewable_queued_post_topic) }
+
+          it "works" do
+            args = { revise_reason: "Duplicate", revise_feedback: "This is old news" }
+            expect { reviewable.perform(moderator, :revise_and_reject_post, args) }.to change {
+              Topic.where(archetype: Archetype.private_message).count
+            }
+            topic = Topic.where(archetype: Archetype.private_message).last
+
+            expect(topic.title).to eq(
+              I18n.t(
+                "system_messages.reviewable_queued_post_revise_and_reject_new_topic.subject_template",
+                topic_title: reviewable.payload["title"],
+              ),
+            )
+            translation_params = {
+              username: reviewable.target_created_by.username,
+              topic_title: reviewable.payload["title"],
+              topic_url: nil,
+              reason: args[:revise_reason],
+              feedback: args[:revise_feedback],
+              original_post: reviewable.payload["raw"],
+              site_name: SiteSetting.title,
+            }
+            expect(topic.first_post.raw.chomp).to eq(
+              I18n.t(
+                "system_messages.reviewable_queued_post_revise_and_reject_new_topic.text_body_template",
+                translation_params,
+              ).chomp,
+            )
+          end
+        end
       end
 
       context "with delete_user" do