From c9f6beba05d1fc6ecab60b6de305792c6ad25698 Mon Sep 17 00:00:00 2001
From: Guo Xiang Tan <tgx_world@hotmail.com>
Date: Fri, 26 Apr 2019 10:25:55 +0800
Subject: [PATCH] FIX: Incorrect DB query for `AddUploadsToCategories`
 migration.

This is a regression as a result of 7896c74c2bd161f85c976fcd8468797721df30d9. Most instances would have ran the migrations and some might have run this migration with the incorrect query. Impact of this is small for now but I'm fixing this for correctness purposes.
---
 ...0161202034856_add_uploads_to_categories.rb | 16 +++----
 .../migrate/add_uploads_to_categories_spec.rb | 44 +++++++++++++++++++
 2 files changed, 52 insertions(+), 8 deletions(-)
 create mode 100644 spec/db/migrate/add_uploads_to_categories_spec.rb

diff --git a/db/migrate/20161202034856_add_uploads_to_categories.rb b/db/migrate/20161202034856_add_uploads_to_categories.rb
index 7aa3b646283..92522f76645 100644
--- a/db/migrate/20161202034856_add_uploads_to_categories.rb
+++ b/db/migrate/20161202034856_add_uploads_to_categories.rb
@@ -4,19 +4,19 @@ class AddUploadsToCategories < ActiveRecord::Migration[4.2]
     add_column :categories, :uploaded_background_id, :integer, index: true
 
     execute <<~SQL
-    UPDATE categories
+    UPDATE categories c1
     SET uploaded_logo_id = u.id
-    FROM categories c
-    LEFT JOIN uploads u ON u.url = c.logo_url
-    WHERE u.url IS NOT NULL
+    FROM categories c2
+    INNER JOIN uploads u ON u.url = c2.logo_url
+    WHERE c1.id = c2.id
     SQL
 
     execute <<~SQL
-    UPDATE categories
+    UPDATE categories c1
     SET uploaded_background_id = u.id
-    FROM categories c
-    LEFT JOIN uploads u ON u.url = c.background_url
-    WHERE u.url IS NOT NULL
+    FROM categories c2
+    INNER JOIN uploads u ON u.url = c2.background_url
+    WHERE c1.id = c2.id
     SQL
   end
 end
diff --git a/spec/db/migrate/add_uploads_to_categories_spec.rb b/spec/db/migrate/add_uploads_to_categories_spec.rb
new file mode 100644
index 00000000000..b349a3172fe
--- /dev/null
+++ b/spec/db/migrate/add_uploads_to_categories_spec.rb
@@ -0,0 +1,44 @@
+require 'rails_helper'
+require 'migration/column_dropper'
+require_relative '../../../db/migrate/20161202034856_add_uploads_to_categories'
+
+RSpec.describe AddUploadsToCategories do
+  before do
+    %i{logo_url background_url}.each do |column|
+      DB.exec("ALTER TABLE categories ADD COLUMN #{column} VARCHAR;")
+    end
+
+    %i{uploaded_logo_id uploaded_background_id}.each do |column|
+      DB.exec("ALTER TABLE categories DROP COLUMN IF EXISTS #{column}")
+    end
+  end
+
+  it "should migrate the data properly" do
+    upload1 = Fabricate(:upload)
+    upload2 = Fabricate(:upload)
+
+    category1 = Fabricate(:category,
+      logo_url: upload1.url,
+      background_url: upload2.url
+    )
+
+    category2 = Fabricate(:category,
+      logo_url: upload2.url,
+      background_url: upload1.url
+    )
+
+    silence_stdout { described_class.new.up }
+
+    Discourse.reset_active_record_cache
+
+    category1.reload
+
+    expect(category1.uploaded_logo_id).to eq(upload1.id)
+    expect(category1.uploaded_background_id).to eq(upload2.id)
+
+    category2.reload
+
+    expect(category2.uploaded_logo_id).to eq(upload2.id)
+    expect(category2.uploaded_background_id).to eq(upload1.id)
+  end
+end