#399

backend/app/services/post_import_previewer.rb

@@ -164,7 +164,10 @@ class PostImportPreviewer
                     video_ms: parse_duration(attributes['duration'], errors))
     post.valid?
     post.errors.each { |error| (errors[error.attribute] ||= []) << error.message }
-    errors.delete(:url)
+    if errors[:url]
+      errors[:url].reject! { |message| message.include?('すでに存在') || message.include?('taken') }
+      errors.delete(:url) if errors[:url].empty?
+    end
   end
 
   def parse_duration value, errors

backend/app/services/post_import_runner.rb

@@ -90,6 +90,11 @@ class PostImportRunner
       raise ArgumentError, '取込行の形式が不正です．'
     end
 
-    row.to_h.deep_transform_keys { _1.to_s.underscore }
+    normalised = row.to_h.deep_transform_keys { _1.to_s.underscore }
+    source_row = Integer(normalised['source_row'], exception: false)
+    raise ArgumentError, '元行番号が不正です．' if source_row.nil? || source_row <= 0
+
+    normalised['source_row'] = source_row
+    normalised
   end
 end