Project#default_branch use repo HEAD instead of DB value now

Drop default_branch field from projects table
Use repository.root_ref as value for defautl_branch method
Fixes issue with default_branch and HEAD getting out of sync
Signed-off-by: Dmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>

app/contexts/projects/update_context.rb

@@ -3,6 +3,16 @@ module Projects
     def execute(role = :default)
       params[:project].delete(:namespace_id)
       params[:project].delete(:public) unless can?(current_user, :change_public_mode, project)
+      new_branch = params[:project].delete(:default_branch)
+
+      if project.repository.exists? && new_branch != project.repository.root_ref
+        GitlabShellWorker.perform_async(
+          :update_repository_head,
+          project.path_with_namespace,
+          new_branch
+        )
+      end
+
       project.update_attributes(params[:project], as: role)
     end
   end

app/models/project.rb

@@ -28,7 +28,7 @@ class Project < ActiveRecord::Base
   include Gitlab::ShellAdapter
   extend Enumerize
 
-  attr_accessible :name, :path, :description, :default_branch, :issues_tracker, :label_list,
+  attr_accessible :name, :path, :description, :issues_tracker, :label_list,
     :issues_enabled, :wall_enabled, :merge_requests_enabled, :snippets_enabled, :issues_tracker_id,
     :wiki_enabled, :public, :import_url, :last_activity_at, as: [:default, :admin]
 
@@ -36,6 +36,8 @@ class Project < ActiveRecord::Base
 
   acts_as_taggable_on :labels, :issues_default_labels
 
+  attr_accessor :new_default_branch
+
   # Relations
   belongs_to :creator,      foreign_key: "creator_id", class_name: "User"
   belongs_to :group,        foreign_key: "namespace_id", conditions: "type = 'Group'"
@@ -143,7 +145,7 @@ class Project < ActiveRecord::Base
   end
 
   def repository
-    @repository ||= Repository.new(path_with_namespace, default_branch)
+    @repository ||= Repository.new(path_with_namespace)
   end
 
   def saved?
@@ -451,4 +453,8 @@ class Project < ActiveRecord::Base
   def project_member(user)
     users_projects.where(user_id: user).first
   end
+
+  def default_branch
+    @default_branch ||= repository.root_ref if repository.exists?
+  end
 end

app/models/repository.rb

@@ -3,7 +3,7 @@ class Repository
 
   attr_accessor :raw_repository, :path_with_namespace
 
-  def initialize(path_with_namespace, default_branch)
+  def initialize(path_with_namespace, default_branch = nil)
     @path_with_namespace = path_with_namespace
     @raw_repository = Gitlab::Git::Repository.new(path_to_repo) if path_with_namespace
   rescue Gitlab::Git::Repository::NoRepository

app/observers/project_observer.rb

@@ -30,12 +30,6 @@ class ProjectObserver < BaseObserver
   def after_update(project)
     project.send_move_instructions if project.namespace_id_changed?
     project.rename_repo if project.path_changed?
-
-    GitlabShellWorker.perform_async(
-      :update_repository_head,
-      project.path_with_namespace,
-      project.default_branch
-    ) if project.default_branch_changed?
   end
 
   def before_destroy(project)

db/migrate/20131106151520_remove_default_branch.rb

+class RemoveDefaultBranch < ActiveRecord::Migration
+  def up
+    remove_column :projects, :default_branch
+  end
+
+  def down
+    add_column :projects, :default_branch, :string
+  end
+end

db/schema.rb

@@ -11,7 +11,7 @@
 #
 # It's strongly recommended to check this file into your version control system.
 
-ActiveRecord::Schema.define(:version => 20131009115346) do
+ActiveRecord::Schema.define(:version => 20131106151520) do
 
   create_table "deploy_keys_projects", :force => true do |t|
     t.integer  "deploy_key_id", :null => false
@@ -171,7 +171,6 @@ ActiveRecord::Schema.define(:version => 20131009115346) do
     t.datetime "created_at",                                   :null => false
     t.datetime "updated_at",                                   :null => false
     t.integer  "creator_id"
-    t.string   "default_branch"
     t.boolean  "issues_enabled",         :default => true,     :null => false
     t.boolean  "wall_enabled",           :default => true,     :null => false
     t.boolean  "merge_requests_enabled", :default => true,     :null => false