From b040f85790c61a4155a044f3f1fa198e49a96925 Mon Sep 17 00:00:00 2001
From: Benjamin Neff <benjamin@coding4coffee.ch>
Date: Thu, 24 Aug 2017 22:24:06 +0200
Subject: [PATCH] Remove root_guid from reshares when post is deleted

And cleanup old reshares with deleted root posts

closes #7578
---
 Changelog.md                                             | 1 +
 app/models/post.rb                                       | 4 ++++
 .../20170824202628_cleanup_root_guids_from_reshares.rb   | 9 +++++++++
 spec/models/post_spec.rb                                 | 9 +++++++++
 4 files changed, 23 insertions(+)
 create mode 100644 db/migrate/20170824202628_cleanup_root_guids_from_reshares.rb

diff --git a/Changelog.md b/Changelog.md
index fc4830613..a0a8e9049 100644
--- a/Changelog.md
+++ b/Changelog.md
@@ -5,6 +5,7 @@
 * Remove Internet Explorer workarounds [#7557](https://github.com/diaspora/diaspora/pull/7557)
 * Sort notifications by last interaction [#7568](https://github.com/diaspora/diaspora/pull/7568)
 * Remove tiff support from photos [#7576](https://github.com/diaspora/diaspora/pull/7576)
+* Remove reference from reshares when original post is deleted [#7578](https://github.com/diaspora/diaspora/pull/7578)
 
 ## Bug fixes
 * Fix displaying polls with long answers [#7579](https://github.com/diaspora/diaspora/pull/7579)
diff --git a/app/models/post.rb b/app/models/post.rb
index 4a6c51744..e592400f6 100644
--- a/app/models/post.rb
+++ b/app/models/post.rb
@@ -33,6 +33,10 @@ class Post < ApplicationRecord
     self.touch(:interacted_at)
   end
 
+  before_destroy do
+    reshares.update_all(root_guid: nil) # rubocop:disable Rails/SkipsModelValidations
+  end
+
   #scopes
   scope :includes_for_a_stream, -> {
     includes(:o_embed_cache,
diff --git a/db/migrate/20170824202628_cleanup_root_guids_from_reshares.rb b/db/migrate/20170824202628_cleanup_root_guids_from_reshares.rb
new file mode 100644
index 000000000..7a93cca9d
--- /dev/null
+++ b/db/migrate/20170824202628_cleanup_root_guids_from_reshares.rb
@@ -0,0 +1,9 @@
+class CleanupRootGuidsFromReshares < ActiveRecord::Migration[5.1]
+  def up
+    # rubocop:disable Rails/SkipsModelValidations
+    Reshare.joins("LEFT OUTER JOIN posts as root ON root.guid = posts.root_guid")
+           .where("root.id is NULL AND posts.root_guid is NOT NULL")
+           .update_all(root_guid: nil)
+    # rubocop:enable Rails/SkipsModelValidations
+  end
+end
diff --git a/spec/models/post_spec.rb b/spec/models/post_spec.rb
index fdfc1f4b4..db63c2e26 100644
--- a/spec/models/post_spec.rb
+++ b/spec/models/post_spec.rb
@@ -387,4 +387,13 @@ describe Post, :type => :model do
       expect(post.interacted_at).not_to be_blank
     end
   end
+
+  describe "#before_destroy" do
+    it "removes root_guid from reshares" do
+      post = FactoryGirl.create(:status_message, author: alice.person, public: true)
+      reshare = FactoryGirl.create(:reshare, author: bob.person, root: post)
+      post.destroy!
+      expect(reshare.reload.root_guid).to be_nil
+    end
+  end
 end