From 820e4ac828d2e83bc9c0993b7898eb043128d47f Mon Sep 17 00:00:00 2001
From: Codex Night Worker <codex-night@localhost>
Date: Sun, 15 Nov 2026 13:46:32 +0900
Subject: [PATCH] WIP: preserve failed Codex job issue-242-hhdxc839

---
 .../20261115000000_add_post_count_index_to_tags.rb  |  5 +++++
 backend/db/schema.rb                                |  3 ++-
 backend/spec/models/tag_spec.rb                     | 13 +++++++++++++
 3 files changed, 20 insertions(+), 1 deletion(-)
 create mode 100644 backend/db/migrate/20261115000000_add_post_count_index_to_tags.rb

diff --git a/backend/db/migrate/20261115000000_add_post_count_index_to_tags.rb b/backend/db/migrate/20261115000000_add_post_count_index_to_tags.rb
new file mode 100644
index 0000000..4aa781e
--- /dev/null
+++ b/backend/db/migrate/20261115000000_add_post_count_index_to_tags.rb
@@ -0,0 +1,5 @@
+class AddPostCountIndexToTags < ActiveRecord::Migration[8.0]
+  def change
+    add_index :tags, :post_count
+  end
+end
diff --git a/backend/db/schema.rb b/backend/db/schema.rb
index bf72236..fa8382f 100644
--- a/backend/db/schema.rb
+++ b/backend/db/schema.rb
@@ -10,7 +10,7 @@
 #
 # It's strongly recommended that you check this file into your version control system.
 
-ActiveRecord::Schema[8.0].define(version: 2026_10_15_010000) do
+ActiveRecord::Schema[8.0].define(version: 2026_11_15_000000) do
   create_table "active_storage_attachments", charset: "utf8mb4", collation: "utf8mb4_0900_ai_ci", force: :cascade do |t|
     t.string "name", null: false
     t.string "record_type", null: false
@@ -630,6 +630,7 @@ ActiveRecord::Schema[8.0].define(version: 2026_10_15_010000) do
     t.integer "post_count", default: 0, null: false
     t.integer "version_no", null: false
     t.index ["deprecated_at"], name: "index_tags_on_deprecated_at"
+    t.index ["post_count"], name: "index_tags_on_post_count"
     t.check_constraint "(`deprecated_at` is null) or (`category` <> _utf8mb4'nico')", name: "chk_tags_deprecated_at_not_nico"
     t.check_constraint "`version_no` > 0", name: "chk_tags_version_no_positive"
   end
diff --git a/backend/spec/models/tag_spec.rb b/backend/spec/models/tag_spec.rb
index a247f93..1e2438b 100644
--- a/backend/spec/models/tag_spec.rb
+++ b/backend/spec/models/tag_spec.rb
@@ -2,6 +2,19 @@ require 'rails_helper'
 
 RSpec.describe Tag, type: :model do
   include WikiRecords
+
+  describe 'post_count index' do
+    it 'has a non-unique index on post_count alone' do
+      indexes = described_class.connection.indexes(described_class.table_name)
+
+      expect(indexes).to include(
+          have_attributes(
+              name: 'index_tags_on_post_count',
+              columns: ['post_count'],
+              unique: false))
+    end
+  end
+
   describe '#has_description?' do
     let(:tag) { create(:tag) }