Possible fix for issue #409

lib/acts_as_taggable_on/tag.rb

@@ -1,4 +1,3 @@
-# coding: utf-8
 module ActsAsTaggableOn
   class Tag < ::ActiveRecord::Base
     include ActsAsTaggableOn::Utils
@@ -72,16 +71,29 @@ def self.find_or_create_all_with_like_by_name(*list)
 
       return [] if list.empty?
 
-      existing_tags = Tag.named_any(list)
+      existing_tags = existing_tags_by_list_name(list)
 
       list.map do |tag_name|
-        comparable_tag_name = comparable_name(tag_name)
-        existing_tag = existing_tags.detect { |tag| comparable_name(tag.name) == comparable_tag_name }
+        existing_tag = existing_tags[comparable_name(tag_name)]
 
         existing_tag || Tag.create(:name => tag_name)
       end
     end
 
+    def self.existing_tags_by_list_name(*list)
+      list = [list].flatten
+
+      return [] if list.empty?
+
+      if !ActsAsTaggableOn.strict_case_match && using_case_insensitive_collation?
+        names_to_find = sanitize_sql([(["SELECT '%s' AS name"]  * list.length).join( " UNION ALL " ), *list])
+        tags = ActsAsTaggableOn::Tag.select("#{all_columns}, names.name AS list_name").joins("INNER JOIN (#{names_to_find}) AS names ON tags.name = names.name")
+      else
+        tags = named_any(list).select("#{all_columns}, #{name_column} AS list_name")
+      end
+      Hash[tags.group_by { |tag| comparable_name(tag.list_name) }.map{|k,v| [k,v.first]}]
+    end
+
     ### INSTANCE METHODS:
 
     def ==(object)
@@ -99,12 +111,20 @@ def count
     class << self
       private
 
+      def all_columns
+        "#{ActsAsTaggableOn::Tag.table_name}.*"
+      end
+
+      def name_column
+        "#{ActsAsTaggableOn::Tag.table_name}.name"
+      end
+
       def comparable_name(str)
         as_8bit_ascii(str).downcase
       end
 
       def binary
-        /mysql/ === ActiveRecord::Base.connection_config[:adapter] ? "BINARY " : nil
+        using_mysql? ? "BINARY " : nil
       end
 
       def as_8bit_ascii(string)

lib/acts_as_taggable_on/utils.rb

@@ -15,10 +15,18 @@ def using_sqlite?
         ::ActiveRecord::Base.connection && ::ActiveRecord::Base.connection.adapter_name == 'SQLite'
       end
 
+      def using_mysql?
+        ::ActiveRecord::Base.connection && ::ActiveRecord::Base.connection.adapter_name.downcase =~ /mysql/
+      end
+
+      def using_case_insensitive_collation?
+        using_mysql? && ::ActiveRecord::Base.connection.collation =~ /_ci\Z/
+      end
+
       def sha_prefix(string)
         Digest::SHA1.hexdigest("#{string}#{rand}")[0..6]
       end
-      
+
       private
       def like_operator
         using_postgresql? ? 'ILIKE' : 'LIKE'

spec/acts_as_taggable_on/tag_spec.rb

@@ -89,6 +89,27 @@
     end
   end
 
+  if ActsAsTaggableOn::Tag.using_case_insensitive_collation?
+    describe "find or create with a case insensitive and accent insensitive database" do
+      before(:each) do
+        @tag.name = "inupiat"
+        @tag.save
+      end
+
+      it "should find existing tags case and accent insensitivly" do
+        ActsAsTaggableOn::Tag.find_or_create_all_with_like_by_name("IÑUPIAT").should == [@tag]
+      end
+
+      it "should find existing tags accent insensitivly" do
+        ActsAsTaggableOn::Tag.find_or_create_all_with_like_by_name("iñupiat").should == [@tag]
+      end
+
+      it "should not let tags with single quotes break the query" do
+        ActsAsTaggableOn::Tag.find_or_create_all_with_like_by_name("their's").map(&:name).should == ["their's"]
+      end
+    end
+  end
+
   it "should require a name" do
     @tag.valid?
 
@@ -192,12 +213,12 @@
         duplicate_tag.stub(:validates_name_uniqueness?).and_return(false)
         duplicate_tag.save
         duplicate_tag.should be_persisted
-      end  
+      end
     end
 
     context "when do need unique names" do
       it "should run uniqueness validation" do
-        duplicate_tag.should_not be_valid        
+        duplicate_tag.should_not be_valid
       end
 
       it "add error to name" do

spec/acts_as_taggable_on/utils_spec.rb

@@ -18,4 +18,39 @@
       TaggableModel.send(:like_operator).should == "LIKE"
     end
   end
+
+  describe "using_mysql?" do
+    it "should return true when the adapter is mysql" do
+      TaggableModel.connection.stub(:adapter_name).and_return("MySQL2")
+      TaggableModel.using_mysql?.should be_true
+    end
+
+    it "should return false when the adapter is not mysql" do
+      TaggableModel.connection.stub(:adapter_name).and_return("PostgreSQL")
+      TaggableModel.using_mysql?.should be_false
+    end
+  end
+
+  describe "using_case_insensitive_collation?" do
+    context "when the adapter is mysql" do
+      before do
+        TaggableModel.connection.stub(:adapter_name).and_return("MySQL2")
+      end
+
+      it "should return true when the collation is case insensitive" do
+        TaggableModel.connection.stub(:collation).and_return("utf8_unicode_ci")
+        TaggableModel.using_case_insensitive_collation?.should be_true
+      end
+
+      it "should return false when the adapter is case sensitive" do
+        TaggableModel.connection.stub(:collation).and_return("utf8_bin")
+        TaggableModel.using_case_insensitive_collation?.should be_false
+      end
+    end
+
+    it "should return false when the adapter is not mysql" do
+      TaggableModel.connection.stub(:adapter_name).and_return("PostgreSQL")
+      TaggableModel.using_case_insensitive_collation?.should be_false
+    end
+  end
 end