Fix #3639: Favorite count pixiv tags aren't skipped by translated tags.

app/logical/sources/strategies/base.rb

@@ -83,6 +83,8 @@ module Sources
 
       # Given a tag from the source site, should return an array of corresponding Danbooru tags.
       def translate_tag(untranslated_tag)
+        return [] if untranslated_tag.blank?
+
         translated_tag_names = WikiPage.active.other_names_equal(untranslated_tag).uniq.pluck(:title)
         translated_tag_names = TagAlias.to_aliased(translated_tag_names)
         translated_tags = Tag.where(name: translated_tag_names)

app/logical/sources/strategies/pixiv.rb

@@ -57,7 +57,7 @@ module Sources
       end
 
       def translate_tag(tag)
-        normalized_tag = tag.gsub(/\A(\S+?)_?\d+users入り\Z/i, '\1')
+        normalized_tag = tag.gsub(/\d+users入り\z/i, "")
 
         translated_tags = super(normalized_tag)
         if translated_tags.empty? && normalized_tag.include?("/")

test/unit/sources/pixiv_test.rb

@@ -228,6 +228,15 @@ module Sources
 
           assert_equal([toosaka_rin], @site.translate_tag("遠坂凛"))
         end
+
+        should "not translate '1000users入り' to '1'" do
+          FactoryBot.create(:tag, name: "1", post_count: 1)
+          source = get_source("https://www.pixiv.net/member_illust.php?mode=medium&illust_id=60665428")
+          tags = %w[Fate/GrandOrder グランブルーファンタジー 手袋 1000users入り]
+
+          assert_equal(tags.sort, source.tags.map(&:first).sort)
+          assert_equal(["fate/grand_order"], source.translated_tags.map(&:first))
+        end
       end
     end
   end