Fix ordering issue

app/models/ci/project.rb

@@ -33,7 +33,7 @@ module Ci
     belongs_to :gl_project, class_name: '::Project', foreign_key: :gitlab_id
-    has_many :commits, ->() { order(:committed_at) }, dependent: :destroy, class_name: 'Ci::Commit'
+    has_many :commits, ->() { order('CASE WHEN commits.committed_at IS NULL THEN 0 ELSE 1 END', :committed_at, :id) }, dependent: :destroy, class_name: 'Ci::Commit'
     has_many :builds, through: :commits, dependent: :destroy, class_name: 'Ci::Build'
     has_many :runner_projects, dependent: :destroy, class_name: 'Ci::RunnerProject'
     has_many :runners, through: :runner_projects, class_name: 'Ci::Runner'

db/migrate/20150916145038_add_index_for_committed_at_and_id.rb

+class AddIndexForCommittedAtAndId < ActiveRecord::Migration
+  def change
+    add_index :ci_commits, [:project_id, :committed_at, :id]
+  end
+end

db/schema.rb

@@ -11,7 +11,7 @@
 #
 # It's strongly recommended that you check this file into your version control system.
-ActiveRecord::Schema.define(version: 20150914215247) do
+ActiveRecord::Schema.define(version: 20150916145038) do
   # These are extensions that must be enabled in order to support this database
   enable_extension "plpgsql"
@@ -118,6 +118,7 @@ ActiveRecord::Schema.define(version: 20150914215247) do
     t.datetime "committed_at"
   end
+  add_index "ci_commits", ["project_id", "committed_at", "id"], name: "index_ci_commits_on_project_id_and_committed_at_and_id", using: :btree
   add_index "ci_commits", ["project_id", "committed_at"], name: "index_ci_commits_on_project_id_and_committed_at", using: :btree
   add_index "ci_commits", ["project_id", "sha"], name: "index_ci_commits_on_project_id_and_sha", using: :btree
   add_index "ci_commits", ["project_id"], name: "index_ci_commits_on_project_id", using: :btree

spec/models/ci/project_spec.rb

@@ -61,6 +61,24 @@ describe Ci::Project do
     end
   end
+  describe 'ordered commits' do
+    let (:project) { FactoryGirl.create :ci_project }
+
+    it 'returns ordered list of commits' do
+      commit1 = FactoryGirl.create :ci_commit, committed_at: 1.hour.ago, project: project
+      commit2 = FactoryGirl.create :ci_commit, committed_at: 2.hour.ago, project: project
+      project.commits.should == [commit2, commit1]
+    end
+
+    it 'returns commits ordered by committed_at and id, with nulls last' do
+      commit1 = FactoryGirl.create :ci_commit, committed_at: 1.hour.ago, project: project
+      commit2 = FactoryGirl.create :ci_commit, committed_at: nil, project: project
+      commit3 = FactoryGirl.create :ci_commit, committed_at: 2.hour.ago, project: project
+      commit4 = FactoryGirl.create :ci_commit, committed_at: nil, project: project
+      project.commits.should == [commit2, commit4, commit3, commit1]
+    end
+  end
+
   context :valid_project do
     let(:project) { FactoryGirl.create :ci_project }