fix error handling for invalid characters in tags

app/models/meta_tag.rb

@@ -24,19 +24,25 @@ class MetaTag < ActiveRecord::Base
     :through => :taggings, 
     :dependent => :destroy,
     :skip_duplicates => false
-
+  
   def after_save
     # if you allow editable tag names, you might want before_save instead 
     self.name = name.downcase.strip.squeeze(" ")
   end
-
-  def self.cloud(args = {})
-    find(:all, :select => 'meta_tags.*, count(*) as popularity',
+
+  class << self
+    def find_or_create_by_name!(name)
+      find_by_name(name) || create!(:name => name)
+    end
+
+    def cloud(args = {})
+      find(:all, :select => 'meta_tags.*, count(*) as popularity',
       :limit => args[:limit] || 5,
       :joins => "JOIN taggings ON taggings.meta_tag_id = meta_tags.id",
       :conditions => args[:conditions],
       :group => "meta_tags.id, meta_tags.name",
       :order => "popularity DESC" )
+    end
   end
 
   def <=>(other)

lib/tagging_methods.rb

@@ -10,8 +10,10 @@ def tag_with tags
 
     tags.split(MetaTag::DELIMITER).each do |tag|
       begin
-        MetaTag.find_or_create_by_name(tag.strip.squeeze(" ")).taggables << self
-      rescue ActiveRecord::StatementInvalid => e
+        MetaTag.find_or_create_by_name!(tag.strip.squeeze(" ")).taggables << self
+      rescue ActiveRecord::RecordInvalid => e
+        self.errors.add(:tags, e.record.errors.on(:name))
+      rescue ActiveRecord::StatementInvalid => e  
         # With SQLite3 - a duplicate tagging will result in the following message:
         # SQLite3::SQLException: SQL logic error or missing database: INSERT INTO taggings ("meta_tag_id", "taggable_type", "taggable_id") VALUES(11, 'Page', 74)
         # raise unless e.to_s =~ /duplicate/i