attempt to fix conflicts with mirror URL callbacks

app/models/project.rb

@@ -90,7 +90,8 @@ class Project < ActiveRecord::Base
   after_destroy :remove_pages
 
   after_update :update_forks_visibility_level
-  after_update :remove_mirror_repository_reference, if: :import_url_changed?
+  after_update :remove_mirror_repository_reference,
+               if: ->(project) { project.mirror? && project.import_url_changed? }
 
   ActsAsTaggableOn.strict_case_match = true
   acts_as_taggable_on :tags
@@ -1261,6 +1262,8 @@ class Project < ActiveRecord::Base
   end
 
   def remove_mirror_repository_reference
+    # return if it's the first assignment
+    return unless changes['import_url'] && changes['import_url'].first
     repository.remove_remote(Repository::MIRROR_REMOTE)
   end
 

db/schema.rb

@@ -808,8 +808,8 @@ ActiveRecord::Schema.define(version: 20160414064845) do
     t.integer "project_id"
     t.text    "data"
     t.text    "encrypted_credentials"
-    t.text    "encrypted_credentials_iv"
-    t.text    "encrypted_credentials_salt"
+    t.string  "encrypted_credentials_iv"
+    t.string  "encrypted_credentials_salt"
   end
 
   create_table "projects", force: :cascade do |t|