#399

backend/app/services/post_import_runner.rb

@@ -46,6 +46,13 @@ class PostImportRunner
     end
 
     { source_row: row['source_row'], status: 'failed', errors: e.record.errors.to_hash }
+  rescue ActiveRecord::RecordNotUnique
+    existing_post = existing_post_for_race(row)
+    raise unless existing_post
+
+    { source_row: row['source_row'],
+      status: 'skipped',
+      existing_post_id: existing_post.id }
   rescue Tag::NicoTagNormalisationError
     { source_row: row['source_row'],
       status: 'failed',
@@ -66,8 +73,10 @@ class PostImportRunner
       errors: { base: ['登録中にエラーが発生しました．'] } }
   end
 
-  def existing_post_for_race row, record
-    return nil unless record.errors.of_kind?(:url, :taken)
+  def existing_post_for_race row, record = nil
+    if record && !(record.errors.of_kind?(:url, :taken))
+      return nil
+    end
 
     normal_url = PostUrlNormaliser.normalise(row['url'])
     return nil if normal_url.blank?