#419

backend/app/models/tag_name_sanitisation_rule.rb

@@ -10,8 +10,9 @@ class TagNameSanitisationRule < ApplicationRecord
   validate :source_pattern_must_be_regexp
 
   class << self
-    def sanitise(name) =
-        rules.reduce(name.dup) { |name, (pattern, replacement)| name.gsub(pattern, replacement) }
+    def sanitise(name)
+      rules.reduce(name.dup) { |name, (pattern, replacement)| name.gsub(pattern, replacement) }
+    end
 
     def apply!
       TagName.find_each do |tn|

backend/lib/tasks/sync_nico.rake

@@ -143,7 +143,8 @@ namespace :nico do
       desired_tag_ids = kept_tag_ids.to_a
 
       datum['tags'].each do |raw|
-        tag = ExternalTag.find_or_create_by!(platform: :nico, name: raw)
+        name = TagNameSanitisationRule.sanitise(raw)
+        tag = ExternalTag.find_or_create_by!(platform: :nico, name:)
 
         unless tag.nico_tag_versions.exists?
           NicoTagVersionRecorder.record!(external_tag: tag,

backend/spec/tasks/nico_sync_spec.rb

@@ -15,6 +15,11 @@ RSpec.describe 'nico:sync' do
     NicoTagRelation.create!(nico_tag_id: nico_tag.id, tag_id: tag.id)
   end
 
+  def create_nico_sanitisation_rules!
+    TagNameSanitisationRule.create!(priority: 20, source_pattern: '\\?', replacement: '_')
+    TagNameSanitisationRule.create!(priority: 40, source_pattren: '_$', replacement: '')
+  end
+
   it '既存 post を見つけて、nico tag と linked tag を追加し、差分が出たら bot を付ける' do
     # 既存 post（正規表現で拾われるURL）
     post = Post.create!(
@@ -435,17 +440,24 @@ RSpec.describe 'nico:sync' do
     expect(post.tags.map(&:name)).not_to include('bot操作')
   end
 
-  it '外部タグが新規記載されたとき，その時点の連携タグを記載する' do
+  it 'サニタイズ後の既存外部タグを再利用し、その連携タグを記載する' do
     post = create_nico_sync_post!
 
+    create_nico_sanitisation_rules!
+
     external_tag = create_external_tag!('AAA')
     linked_tag = create_tag!('spec_linked', category: :general)
     link_nico_to_tag!(external_tag, linked_tag)
 
-    run_nico_sync_with_tags!(['AAA'])
+    expect {
+      run_nico_sync_with_tags!(['AAA?'])
+    }.not_to change(ExternalTag, :count)
 
-    expect(post.reload.external_tags).to include(external_tag)
+    post.reload
+
+    expect(post.external_tags).to contain_exactly(external_tag)
     expect(post.tags).to include(linked_tag)
+    expect(ExternalTag.exists?(platform: :nico, name: 'AAA?')).to be(false)
   end
 
   it '外部タグに差分がない場合，内外マッピングが変はっても連携タグを再評価しない' do
@@ -520,4 +532,51 @@ RSpec.describe 'nico:sync' do
     # 再記載時点の内外マッピングが新たに適用される．
     expect(post.tags).to include(new_linked_tag)
   end
+
+  it '外部タグだけの変更では bot を付けず、投稿履歴を記録する' do
+    post = create_nico_sync_post!
+    PostVersionRecorder.record!(post:, event_type: :create, created_by_user: nil)
+
+    create_nico_sanitisation_rules!
+
+    expect {
+      run_nico_sync_with_tags!(['AAA?', 'AAA?'])
+    }.to change(PostVersion, :count).by(1)
+        .and change(ExternalTag, :count).by(1)
+        .and change(PostExternalTag, :count).by(1)
+        .and change(NicoTagVersion, :count).by(1)
+        .and change(TagName, :count).by(0)
+
+    external = post.reload.external_tags.sole
+
+    expect(external).to have_attributes(
+        platform: 'nico',
+        name: 'AAA')
+    expect(ExternalTag.exists?(platform: :nico, name: 'AAA?')).to be(false)
+
+    expect(post.tags.map(&:name)).not_to include('bot操作')
+    expect(post.post_versions.order(:version_no).last.tags_json)
+        .to include('external_tag_id' => external.id)
+
+    expect {
+      run_nico_sync_with_tags!(['AAA?'])
+    }.to change(PostVersion, :count).by(0)
+        .and change(NicoTagVersion, :count).by(0)
+
+    expect {
+      run_nico_sync_with_tags!([])
+    }.to change(PostVersion, :count).by(1)
+
+    expect(post.reload.external_tags).to be_empty
+    expect(post.tags.map(&:name)).not_to include('bot操作')
+  end
+
+  it 'nico: prefix を含む従来の規則で外部タグ名をサニタイズする' do
+    post = create_nico_sync_post!
+
+    run_nico_sync_with_tags!(['foo:_bar'])
+
+    expect(post.reload.external_tags.sole)
+        .to have_attributes(platform: 'nico', name: 'foo:_bar')
+  end
 end