Fix implication antecedents with aliases

app/models/tag_implication.rb

@@ -8,6 +8,7 @@ class TagImplication < ActiveRecord::Base
   validates_presence_of :creator_id, :antecedent_name, :consequent_name
   validates_uniqueness_of :antecedent_name, :scope => :consequent_name
   validate :absence_of_circular_relation
+  validate :antecedent_is_not_aliased
   validate :consequent_is_not_aliased
 
   module DescendantMethods
@@ -126,6 +127,14 @@ class TagImplication < ActiveRecord::Base
     end
   end
 
+  def antecedent_is_not_aliased
+    # We don't want to implicate a -> b if a is already aliased to c
+    if TagAlias.exists?(["antecedent_name = ?", antecedent_name])
+      self.errors[:base] << "Antecedent tag must not be aliased to another tag"
+      false
+    end
+  end
+
   def consequent_is_not_aliased
     # We don't want to implicate a -> b if b is already aliased to c
     if TagAlias.exists?(["antecedent_name = ?", consequent_name])

db/migrate/20131228230219_update_aliased_implication_antecedents.rb

@@ -0,0 +1,19 @@
+class UpdateAliasedImplicationAntecedents < ActiveRecord::Migration
+  def change
+    execute "set statement_timeout = 0"
+    TagImplication.find_each do |ti|
+      ta = TagAlias.where("antecedent_name = ? AND status != ?", ti.antecedent_name, "pending").first
+      if ta
+        if ta.consequent_name == ti.consequent_name
+          ti.destroy
+        elsif TagImplication.where("antecedent_name = ? AND consequent_name = ?", ta.consequent_name, ti.consequent_name).exists?
+          ti.destroy
+        else
+          ti.antecedent_name = ta.consequent_name
+          ti.save
+        end
+        ta.update_posts
+      end
+    end
+  end
+end