FIX: when deleting users with solved posts (#297)

it would raise an error because we delete the topic before and we need the topic record to update various meta data.

This ensures we load the "deleted" version in such cases.

Internal ref - t/130797

plugin.rb

@@ -137,6 +137,9 @@ after_initialize do
 
     def self.unaccept_answer!(post, topic: nil)
       topic ||= post.topic
+      topic ||= Topic.unscoped.find_by(id: post.topic_id)
+
+      return if topic.nil?
 
       DistributedMutex.synchronize("discourse_solved_toggle_answer_#{topic.id}") do
         post.custom_fields.delete(IS_ACCEPTED_ANSWER_CUSTOM_FIELD)

spec/integration/solved_spec.rb

@@ -446,6 +446,7 @@ RSpec.describe "Managing Posts solved status" do
 
       sign_in(user)
     end
+
     describe "updating assignment status on solve when assignment_status_on_solve is set" do
       it "update all assignments to this status when a post is accepted" do
         assigner = Assigner.new(p1.topic, user)
@@ -483,11 +484,11 @@ RSpec.describe "Managing Posts solved status" do
         group.add(user_3)
 
         topic_question = Fabricate(:topic, user: user_1)
-        post_question = Fabricate(:post, topic: topic_question, user: user_1)
 
-        user_2_response = Fabricate(:post, topic: topic_question, user: user_2)
-        assigner = Assigner.new(topic_question, user_2)
-        result = assigner.assign(user_2)
+        Fabricate(:post, topic: topic_question, user: user_1)
+        Fabricate(:post, topic: topic_question, user: user_2)
+
+        result = Assigner.new(topic_question, user_2).assign(user_2)
         expect(result[:success]).to eq(true)
 
         post_response = Fabricate(:post, topic: topic_question, user: user_3)
@@ -503,32 +504,50 @@ RSpec.describe "Managing Posts solved status" do
         expect(post_response.assignment.assigned_to_id).to eq(user_3.id)
       end
 
-      describe "assigned topic reminder"
-      it "excludes solved topics when ignore_solved_topics_in_assigned_reminder is false" do
-        other_topic = Fabricate(:topic, title: "Topic that should be there")
-        post = Fabricate(:post, topic: other_topic, user: user)
+      describe "assigned topic reminder" do
+        it "excludes solved topics when ignore_solved_topics_in_assigned_reminder is false" do
+          other_topic = Fabricate(:topic, title: "Topic that should be there")
+          post = Fabricate(:post, topic: other_topic, user: user)
 
-        other_topic2 = Fabricate(:topic, title: "Topic that should be there2")
-        post2 = Fabricate(:post, topic: other_topic2, user: user)
+          other_topic2 = Fabricate(:topic, title: "Topic that should be there2")
+          post2 = Fabricate(:post, topic: other_topic2, user: user)
 
-        Assigner.new(post.topic, user).assign(user)
-        Assigner.new(post2.topic, user).assign(user)
+          Assigner.new(post.topic, user).assign(user)
+          Assigner.new(post2.topic, user).assign(user)
 
-        reminder = PendingAssignsReminder.new
-        topics = reminder.send(:assigned_topics, user, order: :asc)
-        expect(topics.to_a.length).to eq(2)
+          reminder = PendingAssignsReminder.new
+          topics = reminder.send(:assigned_topics, user, order: :asc)
+          expect(topics.to_a.length).to eq(2)
 
-        DiscourseSolved.accept_answer!(post2, Discourse.system_user)
-        topics = reminder.send(:assigned_topics, user, order: :asc)
-        expect(topics.to_a.length).to eq(2)
-        expect(topics).to include(other_topic2)
+          DiscourseSolved.accept_answer!(post2, Discourse.system_user)
+          topics = reminder.send(:assigned_topics, user, order: :asc)
+          expect(topics.to_a.length).to eq(2)
+          expect(topics).to include(other_topic2)
 
-        SiteSetting.ignore_solved_topics_in_assigned_reminder = true
-        topics = reminder.send(:assigned_topics, user, order: :asc)
-        expect(topics.to_a.length).to eq(1)
-        expect(topics).not_to include(other_topic2)
-        expect(topics).to include(other_topic)
+          SiteSetting.ignore_solved_topics_in_assigned_reminder = true
+          topics = reminder.send(:assigned_topics, user, order: :asc)
+          expect(topics.to_a.length).to eq(1)
+          expect(topics).not_to include(other_topic2)
+          expect(topics).to include(other_topic)
+        end
       end
     end
   end
+
+  describe "#unaccept_answer!" do
+    it "works even when the topic has been deleted" do
+      user = Fabricate(:user, trust_level: 1)
+      topic = Fabricate(:topic, user:)
+      reply = Fabricate(:post, topic:, user:, post_number: 2)
+
+      DiscourseSolved.accept_answer!(reply, user)
+
+      topic.trash!(Discourse.system_user)
+      reply.reload
+
+      expect(reply.topic).to eq(nil)
+
+      expect { DiscourseSolved.unaccept_answer!(reply) }.not_to raise_error
+    end
+  end
 end