From 5e2815932655af7085322388095984e082c1199e Mon Sep 17 00:00:00 2001
From: miteruzo <miteruzo@naver.com>
Date: Wed, 11 Mar 2026 12:43:08 +0900
Subject: [PATCH] #287

---
 backend/app/models/tag.rb                          |  6 +++++-
 .../20260311123100_add_discarded_at_to_tags.rb     |  6 ++++++
 backend/db/schema.rb                               | 14 +++++++++++++-
 3 files changed, 24 insertions(+), 2 deletions(-)
 create mode 100644 backend/db/migrate/20260311123100_add_discarded_at_to_tags.rb

diff --git a/backend/app/models/tag.rb b/backend/app/models/tag.rb
index eaf51da..d083dc6 100644
--- a/backend/app/models/tag.rb
+++ b/backend/app/models/tag.rb
@@ -1,8 +1,12 @@
 class Tag < ApplicationRecord
+  include Discard::Model
+
   class NicoTagNormalisationError < ArgumentError
     ;
   end
 
+  default_scope -> { kept }
+
   has_many :post_tags, inverse_of: :tag
   has_many :active_post_tags, -> { kept }, class_name: 'PostTag', inverse_of: :tag
   has_many :post_tags_with_discarded, -> { with_discarded }, class_name: 'PostTag'
@@ -160,7 +164,7 @@ class Tag < ApplicationRecord
         end
 
         tag_name = st.tag_name
-        st.destroy!
+        st.discard!
         tag_name.reload
         tag_name.update!(canonical: target_tag.tag_name)
       end
diff --git a/backend/db/migrate/20260311123100_add_discarded_at_to_tags.rb b/backend/db/migrate/20260311123100_add_discarded_at_to_tags.rb
new file mode 100644
index 0000000..4bd5c5d
--- /dev/null
+++ b/backend/db/migrate/20260311123100_add_discarded_at_to_tags.rb
@@ -0,0 +1,6 @@
+class AddDiscardedAtToTags < ActiveRecord::Migration[8.0]
+  def change
+    add_column :tags, :discarded_at, :datetime
+    add_index :tags, :discarded_at
+  end
+end
diff --git a/backend/db/schema.rb b/backend/db/schema.rb
index 8077fac..b6ffbd3 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_03_03_122700) do
+ActiveRecord::Schema[8.0].define(version: 2026_03_11_123100) 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
@@ -127,6 +127,16 @@ ActiveRecord::Schema[8.0].define(version: 2026_03_03_122700) do
     t.index ["tag_id"], name: "index_tag_implications_on_tag_id"
   end
 
+  create_table "tag_name_sanitisation_rules", primary_key: "priority", id: :integer, charset: "utf8mb4", collation: "utf8mb4_0900_ai_ci", force: :cascade do |t|
+    t.string "source_pattern", null: false
+    t.string "replacement", null: false
+    t.datetime "created_at", null: false
+    t.datetime "updated_at", null: false
+    t.datetime "discarded_at"
+    t.index ["discarded_at"], name: "index_tag_name_sanitisation_rules_on_discarded_at"
+    t.index ["source_pattern"], name: "index_tag_name_sanitisation_rules_on_source_pattern", unique: true
+  end
+
   create_table "tag_names", charset: "utf8mb4", collation: "utf8mb4_0900_ai_ci", force: :cascade do |t|
     t.string "name", null: false
     t.bigint "canonical_id"
@@ -150,6 +160,8 @@ ActiveRecord::Schema[8.0].define(version: 2026_03_03_122700) do
     t.datetime "created_at", null: false
     t.datetime "updated_at", null: false
     t.integer "post_count", default: 0, null: false
+    t.datetime "discarded_at"
+    t.index ["discarded_at"], name: "index_tags_on_discarded_at"
     t.index ["tag_name_id"], name: "index_tags_on_tag_name_id", unique: true
   end