tags: don't allow aliases inside *_(cosplay) tags.

Don't treat *_(cosplay) tags as being invisibly aliased when a character tag is aliased. For example,
if toosaka_rin is aliased to tohsaka_rin, and toosaka_rin_(cosplay) is later added to a post, don't
magically translate the tag to tohsaka_rin_(cosplay). Instead, treat it as an error to create a
*_(cosplay) tag for an aliased character tag.

This removes some of the complexity and magic behavior surrounding *_(cosplay) tags.

app/logical/post_edit.rb

@@ -42,7 +42,6 @@ class PostEdit
     def tag_names
       tag_names = current_tag_names + effective_added_tag_names - user_removed_tag_names
       tag_names = post.add_automatic_tags(tag_names)
-      tag_names = ::Tag.convert_cosplay_tags(tag_names)
       tag_names += ::Tag.automatic_tags_for(tag_names)
       tag_names += TagImplication.tags_implied_by(tag_names).map(&:name)
       tag_names.uniq.sort

app/logical/tag_name_validator.rb

@@ -46,12 +46,13 @@ class TagNameValidator < ActiveModel::EachValidator
     when "new", "search", "and", "or", "not"
       record.errors.add(attribute, "'#{value}' is a reserved name and cannot be used")
     when /\A(.+)_\(cosplay\)\z/i
-      # XXX don't allow aliases here?
-      tag_name = TagAlias.to_aliased([$1]).first
-      tag = Tag.find_by_name(tag_name)
+      tag_name = $1;
+      char_tag = Tag.find_by_name(tag_name)
 
-      if tag.present? && !tag.empty? && !tag.character?
-        record.errors.add(attribute, "#{tag_name} must be a character tag")
+      if char_tag.present? && char_tag.antecedent_alias.present?
+        record.errors.add(attribute, "'#{value}' is not allowed because '#{tag_name}' is aliased to '#{char_tag.antecedent_alias.consequent_name}'")
+      elsif char_tag.present? && !char_tag.empty? && !char_tag.character?
+        record.errors.add(attribute, "'#{value}' is not allowed because '#{tag_name}' is not a character tag")
       end
     end
   end

app/models/tag.rb

@@ -362,7 +362,7 @@ class Tag < ApplicationRecord
 
   def self.automatic_tags_for(names)
     tags = []
-    tags += names.grep(/\A(.+)_\(cosplay\)\z/i) { TagAlias.to_aliased([$1]).first }
+    tags += names.grep(/\A(.+)_\(cosplay\)\z/i) { $1 }
     tags << "cosplay" if names.any?(/_\(cosplay\)\z/i)
     tags << "school_uniform" if names.any?(/_school_uniform\z/i)
     tags << "meme" if names.any?(/_\(meme\)\z/i)
@@ -370,13 +370,6 @@ class Tag < ApplicationRecord
   end
 
   concerning :CosplayTagMethods do
-    class_methods do
-      def convert_cosplay_tags(tags)
-        cosplay_tags, other_tags = tags.partition {|tag| tag.match(/\A(.+)_\(cosplay\)\Z/) }
-        cosplay_tags.grep(/\A(.+)_\(cosplay\)\Z/) { "#{TagAlias.to_aliased([$1]).first}_(cosplay)" } + other_tags
-      end
-    end
-
     def create_character_tag_for_cosplay_tag
       character_name = name.delete_suffix("_(cosplay)")
       Tag.find_or_create_by_name("char:#{character_name}")

test/unit/bulk_update_request_test.rb

@@ -392,7 +392,6 @@ class BulkUpdateRequestTest < ActiveSupport::TestCase
           should "move the *_(cosplay) tag as well" do
             @post = create(:post, tag_string: "toosaka_rin_(cosplay)")
             @wiki = create(:wiki_page, title: "toosaka_rin_(cosplay)")
-            @ta = create(:tag_alias, antecedent_name: "toosaka_rin", consequent_name: "tohsaka_rin")
 
             create_bur!("rename toosaka_rin -> tohsaka_rin", @admin)
 
@@ -401,6 +400,18 @@ class BulkUpdateRequestTest < ActiveSupport::TestCase
           end
         end
 
+        context "when aliasing a character tag with a *_(cosplay) tag" do
+          should "move the *_(cosplay) tag as well" do
+            @post = create(:post, tag_string: "toosaka_rin_(cosplay)")
+            @wiki = create(:wiki_page, title: "toosaka_rin_(cosplay)")
+
+            create_bur!("alias toosaka_rin -> tohsaka_rin", @admin)
+
+            assert_equal("cosplay tohsaka_rin tohsaka_rin_(cosplay)", @post.reload.tag_string)
+            assert_equal("tohsaka_rin_(cosplay)", @wiki.reload.title)
+          end
+        end
+
         context "when renaming an artist tag with a *_(style) tag" do
           should "move the *_(style) tag as well" do
             create(:tag, name: "tanaka_takayuki", category: Tag.categories.artist)

test/unit/post_test.rb

@@ -577,7 +577,11 @@ class PostTest < ActiveSupport::TestCase
             @post.add_tag("jim_(cosplay)")
             @post.save
 
-            assert(@post.has_tag?("james"), "expected 'jim' to be aliased to 'james'")
+            assert_equal(false, @post.has_tag?("jim_(cosplay)"))
+            assert_equal(false, @post.has_tag?("james_(cosplay)"))
+            assert_equal(false, @post.has_tag?("jim"))
+            assert_equal(false, @post.has_tag?("james"))
+            assert_match(/'jim_\(cosplay\)' is not allowed because 'jim' is aliased to 'james'/, @post.warnings.full_messages.join)
           end
 
           should "apply implications after the character tag is added" do
@@ -1213,6 +1217,7 @@ class PostTest < ActiveSupport::TestCase
           refute(@post.has_tag?("little_red_riding_hood"))
           refute(@post.has_tag?("cosplay"))
           assert(@post.warnings[:base].grep(/Couldn't add tag/).present?)
+          assert_match(/'little_red_riding_hood_\(cosplay\)' is not allowed because 'little_red_riding_hood' is not a character tag/, @post.warnings.full_messages.join)
         end
 
         should "allow creating a _(cosplay) tag for an empty general tag" do

test/unit/tag_test.rb

@@ -195,11 +195,13 @@ class TagTest < ActiveSupport::TestCase
         setup do
           create(:tag, name: "bkub", category: Tag.categories.artist)
           create(:tag, name: "fumimi", category: Tag.categories.character)
+          create(:tag_alias, antecedent_name: "orin", consequent_name: "kaenbyou_rin")
         end
 
         should allow_value("fumimi_(cosplay)").for(:name)
         should allow_value("new_tag_(cosplay)").for(:name)
         should_not allow_value("bkub_(cosplay)").for(:name)
+        should_not allow_value("orin_(cosplay)").for(:name)
       end
     end
   end