From 942b9126a1bac5b61d640e9f60001a7bf114df34 Mon Sep 17 00:00:00 2001
From: Krzysztof Kotlarek <kotlarek.krzysztof@gmail.com>
Date: Thu, 27 May 2021 08:39:51 +1000
Subject: [PATCH] FIX: no error when double save post with poll (#13111)

Some plugins hook into Post after save to set custom fields and save again.

For example: https://github.com/discourse/discourse-category-experts/blob/main/lib/category_experts/post_handler.rb#L27

Problem is that in case like that `raw_changed?` is false but all callback are triggered. `extracted_polls` is class atribute therefore that should be reset with each attempt.

That was causing an error:
```
#<ActiveRecord::RecordNotUnique: PG::UniqueViolation: ERROR:  duplicate key value violates unique constraint
"index_polls_on_post_id_and_name" DETAIL:  Key (post_id, name)=(8967, poll) already exists.
```
---
 plugins/poll/plugin.rb                | 1 +
 plugins/poll/spec/models/poll_spec.rb | 4 ++++
 2 files changed, 5 insertions(+)

diff --git a/plugins/poll/plugin.rb b/plugins/poll/plugin.rb
index b5f657f8652..02224aea194 100644
--- a/plugins/poll/plugin.rb
+++ b/plugins/poll/plugin.rb
@@ -467,6 +467,7 @@ after_initialize do
 
       after_save do
         polls = self.extracted_polls
+        self.extracted_polls = nil
         next if polls.blank? || !polls.is_a?(Hash)
         post = self
 
diff --git a/plugins/poll/spec/models/poll_spec.rb b/plugins/poll/spec/models/poll_spec.rb
index 1b1f8e8c7f5..03ebcd2fbe4 100644
--- a/plugins/poll/spec/models/poll_spec.rb
+++ b/plugins/poll/spec/models/poll_spec.rb
@@ -81,6 +81,10 @@ describe ::DiscoursePoll::Poll do
 
       expect(poll.post).to eq(post)
     end
+  end
 
+  it "is not throwing an error when double save" do
+    post = Fabricate(:post, raw: "[poll]\n- A\n- B\n[/poll]")
+    expect { post.save! }.not_to raise_error
   end
 end