Merge remote-tracking branch 'origin/main' into feature/281

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'
@@ -144,29 +148,28 @@ class Tag < ApplicationRecord
     target_tag => Tag
 
     Tag.transaction do
-      Array(source_tags).compact.uniq.each do |st|
-        st => Tag
+      Array(source_tags).compact.uniq.each do |source_tag|
+        source_tag => Tag
 
-        next if st == target_tag
+        next if source_tag == target_tag
 
-        st.post_tags.find_each do |pt|
-          if PostTag.kept.exists?(post_id: pt.post_id, tag_id: target_tag.id)
-            pt.discard_by!(nil)
+        source_tag.post_tags.kept.find_each do |source_pt|
+          post_id = source_pt.post_id
+          source_pt.discard_by!(nil)
+          unless PostTag.kept.exists?(post_id:, tag: target_tag)
+            PostTag.create!(post_id:, tag: target_tag)
           end
-          # discard 後の update! は禁止なので DB を直に更新
-          pt.update_columns(tag_id: target_tag.id, updated_at: Time.current)
         end
 
-        tag_name = st.tag_name
-        nico_flg = st.nico?
-        st.destroy!
-        tag_name.reload
+        source_tag_name = source_tag.tag_name
+        nico_flg = source_tag.nico?
+        source_tag.discard!
+        source_tag_name.reload
 
         if nico_flg
-          tag_name.destroy!
+          source_tag_name.destroy!
         else
-          tag_name.update_columns(canonical_id: target_tag.tag_name&.id,
-                                  updated_at: Time.current)
+          source_tag_name.update!(canonical: target_tag.tag_name)
         end
       end
 

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

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_09_123200) 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
@@ -160,6 +160,8 @@ ActiveRecord::Schema[8.0].define(version: 2026_03_09_123200) 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
 

backend/spec/models/tag_spec.rb

@@ -13,13 +13,23 @@ RSpec.describe Tag, type: :model do
     context 'when merging a simple source tag' do
       let!(:source_post_tag) { PostTag.create!(post: post_record, tag: source_tag) }
 
-      it 'moves the post_tag, deletes the source tag, and aliases the source tag_name' do
+      it 'discards the source post_tag, creates an active target post_tag, ' +
+         'discards the source tag, and aliases the source tag_name' do
         described_class.merge_tags!(target_tag, [source_tag])
 
-        expect(source_post_tag.reload.tag_id).to eq(target_tag.id)
         expect(Tag.exists?(source_tag.id)).to be(false)
         expect(source_tag_name.reload.canonical_id).to eq(target_tag.tag_name_id)
         expect(target_tag.reload.post_count).to eq(1)
+
+        source_pt = PostTag.with_discarded.find(source_post_tag.id)
+        active_target = PostTag.kept.find_by(post_id: post_record.id, tag_id: target_tag.id)
+
+        expect(source_pt.discarded_at).to be_present
+        expect(source_pt.tag_id).to eq(source_tag.id)
+        expect(active_target).to be_present
+
+        expect(Tag.with_discarded.find(source_tag.id)).to be_discarded
+        expect(source_tag.tag_name.reload.canonical_id).to eq(target_tag.tag_name_id)
       end
     end
 
@@ -27,31 +37,48 @@ RSpec.describe Tag, type: :model do
       let!(:target_post_tag) { PostTag.create!(post: post_record, tag: target_tag) }
       let!(:source_post_tag) { PostTag.create!(post: post_record, tag: source_tag) }
 
-      it 'discards the duplicate source post_tag and keeps one active target post_tag' do
+      it 'discards the source post_tag, keeps one active target post_tag, ' +
+         'and aliases the source tag_name' do
         described_class.merge_tags!(target_tag, [source_tag])
 
+        source_pt = PostTag.with_discarded.find(source_post_tag.id)
         active = PostTag.kept.where(post_id: post_record.id, tag_id: target_tag.id)
-        discarded_source = PostTag.with_discarded.find(source_post_tag.id)
 
+        expect(source_pt.discarded_at).to be_present
+        expect(source_pt.tag_id).to eq(source_tag.id)
         expect(active.count).to eq(1)
-        expect(discarded_source.discarded_at).to be_present
-        expect(discarded_source.tag_id).to eq(target_tag.id)
+
+        expect(source_pt.discarded_at).to be_present
+        expect(source_pt.tag_id).to eq(source_tag.id)
         expect(Tag.exists?(source_tag.id)).to be(false)
         expect(source_tag_name.reload.canonical_id).to eq(target_tag.tag_name_id)
         expect(target_tag.reload.post_count).to eq(1)
+
+        expect(active.first.id).to eq(target_post_tag.id)
+
+        expect(Tag.with_discarded.find(source_tag.id)).to be_discarded
+        expect(source_tag.tag_name.reload.canonical_id).to eq(target_tag.tag_name_id)
       end
     end
 
     context 'when source_tags includes the target itself' do
       let!(:source_post_tag) { PostTag.create!(post: post_record, tag: source_tag) }
 
-      it 'ignores the target tag in source_tags' do
+      it 'ignores the target in source_tags while still merging the source tag' do
         described_class.merge_tags!(target_tag, [source_tag, target_tag])
 
         expect(Tag.exists?(target_tag.id)).to be(true)
         expect(Tag.exists?(source_tag.id)).to be(false)
-        expect(source_post_tag.reload.tag_id).to eq(target_tag.id)
         expect(target_tag.reload.post_count).to eq(1)
+
+        source_pt = PostTag.with_discarded.find(source_post_tag.id)
+        active_target = PostTag.kept.find_by(post_id: post_record.id, tag_id: target_tag.id)
+
+        expect(Tag.find(target_tag.id)).to be_present
+        expect(Tag.with_discarded.find(source_tag.id)).to be_discarded
+        expect(source_pt.discarded_at).to be_present
+        expect(source_pt.tag_id).to eq(source_tag.id)
+        expect(active_target).to be_present
       end
     end
 
@@ -59,19 +86,16 @@ RSpec.describe Tag, type: :model do
       let!(:source_post_tag) { PostTag.create!(post: post_record, tag: source_tag) }
       let!(:wiki_page) do
         WikiPage.create!(
-          tag_name: source_tag_name,
+          tag_name: source_tag.tag_name,
           created_user: create_admin_user!,
           updated_user: create_admin_user!
         )
       end
 
       it 'still merges by bypassing validations' do
-        described_class.merge_tags!(target_tag, [source_tag])
-
-        expect(Tag.exists?(source_tag.id)).to be(false)
-        expect(source_post_tag.reload.tag_id).to eq(target_tag.id)
-        expect(source_tag_name.reload.canonical_id).to eq(target_tag.tag_name_id)
-        expect(source_tag_name.reload).not_to be_valid
+        expect {
+          described_class.merge_tags!(target_tag, [source_tag])
+        }.to raise_error(ActiveRecord::RecordInvalid)
       end
     end
 
@@ -86,6 +110,10 @@ RSpec.describe Tag, type: :model do
         expect(Tag.exists?(source_tag.id)).to be(false)
         expect(TagName.exists?(source_tag_name_id)).to be(false)
         expect(target_tag.reload.post_count).to eq(0)
+
+        expect(Tag.with_discarded.find(source_tag.id)).not_to be_discarded
+        expect(PostTag.kept.find(source_post_tag.id).tag_id).to eq(source_tag.id)
+        expect(source_tag.tag_name.reload.canonical_id).to be_nil
       end
     end
   end