Merge branch 'master' into refactor/ci-config-add-logical-validationrefactor/ci-config-add-logical-validation

* master: (414 commits)
  Remove suggested colors hover underline
  Fix markdown anchor icon interaction
  Fix expiration date picker after update
  Refactored code to rely less on IDs that could change
  Move CHANGELOG entry for !5858 from 8.11 to 8.12
  Hides merge request section in edit project when disabled
  Fix a typo
  Change minimum Unicorns required to two
  Update memory requirements
  Added `.term-bold` declaration.
  Change the inline code to codeblocks for the new features doc guideline
  Fix GitLab import button
  Rename behaviour to behavior in bug issue template for consistency
  Convert datetime coffeescript spec to ES6
  Align add button on repository view
  Update CHANGELOG with 8.11.4 entries.
  removed null return - renamed 'placeTop' to 'placeProfileAvatarsToTop'
  Refactor Ci::Build#raw_trace
  Move CHANGELOG entry to a proper version
  Change widths of content in MR pipeline tab
  ...

Conflicts:
	lib/gitlab/ci/config/node/jobs.rb

22 files changed, 392 insertions, 751 deletions

diff --git a/app/models/ability.rb b/app/models/ability.rb
index a49dd703926..fa8f8bc3a5f 100644
--- a/app/models/ability.rb
+++ b/app/models/ability.rb
@@ -1,34 +1,5 @@
 class Ability
   class << self
-    # rubocop: disable Metrics/CyclomaticComplexity
-    def allowed(user, subject)
-      return anonymous_abilities(user, subject) if user.nil?
-      return [] unless user.is_a?(User)
-      return [] if user.blocked?
-
-      abilities_by_subject_class(user: user, subject: subject)
-    end
-
-    def abilities_by_subject_class(user:, subject:)
-      case subject
-      when CommitStatus then commit_status_abilities(user, subject)
-      when Project then project_abilities(user, subject)
-      when Issue then issue_abilities(user, subject)
-      when Note then note_abilities(user, subject)
-      when ProjectSnippet then project_snippet_abilities(user, subject)
-      when PersonalSnippet then personal_snippet_abilities(user, subject)
-      when MergeRequest then merge_request_abilities(user, subject)
-      when Group then group_abilities(user, subject)
-      when Namespace then namespace_abilities(user, subject)
-      when GroupMember then group_member_abilities(user, subject)
-      when ProjectMember then project_member_abilities(user, subject)
-      when User then user_abilities
-      when ExternalIssue, Deployment, Environment then project_abilities(user, subject.project)
-      when Ci::Runner then runner_abilities(user, subject)
-      else []
-      end.concat(global_abilities(user))
-    end
-
     # Given a list of users and a project this method returns the users that can
     # read the given project.
     def users_that_can_read_project(users, project)
@@ -61,359 +32,7 @@ class Ability
       issues.select { |issue| issue.visible_to_user?(user) }
     end
 
-    # List of possible abilities for anonymous user
-    def anonymous_abilities(user, subject)
-      if subject.is_a?(PersonalSnippet)
-        anonymous_personal_snippet_abilities(subject)
-      elsif subject.is_a?(ProjectSnippet)
-        anonymous_project_snippet_abilities(subject)
-      elsif subject.is_a?(CommitStatus)
-        anonymous_commit_status_abilities(subject)
-      elsif subject.is_a?(Project) || subject.respond_to?(:project)
-        anonymous_project_abilities(subject)
-      elsif subject.is_a?(Group) || subject.respond_to?(:group)
-        anonymous_group_abilities(subject)
-      elsif subject.is_a?(User)
-        anonymous_user_abilities
-      else
-        []
-      end
-    end
-
-    def anonymous_project_abilities(subject)
-      project = if subject.is_a?(Project)
-                  subject
-                else
-                  subject.project
-                end
-
-      if project && project.public?
-        rules = [
-          :read_project,
-          :read_board,
-          :read_list,
-          :read_wiki,
-          :read_label,
-          :read_milestone,
-          :read_project_snippet,
-          :read_project_member,
-          :read_merge_request,
-          :read_note,
-          :read_pipeline,
-          :read_commit_status,
-          :read_container_image,
-          :download_code
-        ]
-
-        # Allow to read builds by anonymous user if guests are allowed
-        rules << :read_build if project.public_builds?
-
-        # Allow to read issues by anonymous user if issue is not confidential
-        rules << :read_issue unless subject.is_a?(Issue) && subject.confidential?
-
-        rules - project_disabled_features_rules(project)
-      else
-        []
-      end
-    end
-
-    def anonymous_commit_status_abilities(subject)
-      rules = anonymous_project_abilities(subject.project)
-      # If subject is Ci::Build which inherits from CommitStatus filter the abilities
-      rules = filter_build_abilities(rules) if subject.is_a?(Ci::Build)
-      rules
-    end
-
-    def anonymous_group_abilities(subject)
-      rules = []
-
-      group = if subject.is_a?(Group)
-                subject
-              else
-                subject.group
-              end
-
-      rules << :read_group if group.public?
-
-      rules
-    end
-
-    def anonymous_personal_snippet_abilities(snippet)
-      if snippet.public?
-        [:read_personal_snippet]
-      else
-        []
-      end
-    end
-
-    def anonymous_project_snippet_abilities(snippet)
-      if snippet.public?
-        [:read_project_snippet]
-      else
-        []
-      end
-    end
-
-    def anonymous_user_abilities
-      [:read_user] unless restricted_public_level?
-    end
-
-    def global_abilities(user)
-      rules = []
-      rules << :create_group if user.can_create_group
-      rules << :read_users_list
-      rules
-    end
-
-    def project_abilities(user, project)
-      key = "/user/#{user.id}/project/#{project.id}"
-
-      if RequestStore.active?
-        RequestStore.store[key] ||= uncached_project_abilities(user, project)
-      else
-        uncached_project_abilities(user, project)
-      end
-    end
-
-    def uncached_project_abilities(user, project)
-      rules = []
-      # Push abilities on the users team role
-      rules.push(*project_team_rules(project.team, user))
-
-      owner = user.admin? ||
-              project.owner == user ||
-              (project.group && project.group.has_owner?(user))
-
-      if owner
-        rules.push(*project_owner_rules)
-      end
-
-      if project.public? || (project.internal? && !user.external?)
-        rules.push(*public_project_rules)
-
-        # Allow to read builds for internal projects
-        rules << :read_build if project.public_builds?
-
-        unless owner || project.team.member?(user) || project_group_member?(project, user)
-          rules << :request_access if project.request_access_enabled
-        end
-      end
-
-      if project.archived?
-        rules -= project_archived_rules
-      end
-
-      (rules - project_disabled_features_rules(project)).uniq
-    end
-
-    def project_team_rules(team, user)
-      # Rules based on role in project
-      if team.master?(user)
-        project_master_rules
-      elsif team.developer?(user)
-        project_dev_rules
-      elsif team.reporter?(user)
-        project_report_rules
-      elsif team.guest?(user)
-        project_guest_rules
-      else
-        []
-      end
-    end
-
-    def public_project_rules
-      @public_project_rules ||= project_guest_rules + [
-        :download_code,
-        :fork_project,
-        :read_commit_status,
-        :read_pipeline,
-        :read_container_image
-      ]
-    end
-
-    def project_guest_rules
-      @project_guest_rules ||= [
-        :read_project,
-        :read_wiki,
-        :read_issue,
-        :read_board,
-        :read_list,
-        :read_label,
-        :read_milestone,
-        :read_project_snippet,
-        :read_project_member,
-        :read_merge_request,
-        :read_note,
-        :create_project,
-        :create_issue,
-        :create_note,
-        :upload_file
-      ]
-    end
-
-    def project_report_rules
-      @project_report_rules ||= project_guest_rules + [
-        :download_code,
-        :fork_project,
-        :create_project_snippet,
-        :update_issue,
-        :admin_issue,
-        :admin_label,
-        :admin_list,
-        :read_commit_status,
-        :read_build,
-        :read_container_image,
-        :read_pipeline,
-        :read_environment,
-        :read_deployment
-      ]
-    end
-
-    def project_dev_rules
-      @project_dev_rules ||= project_report_rules + [
-        :admin_merge_request,
-        :update_merge_request,
-        :create_commit_status,
-        :update_commit_status,
-        :create_build,
-        :update_build,
-        :create_pipeline,
-        :update_pipeline,
-        :create_merge_request,
-        :create_wiki,
-        :push_code,
-        :resolve_note,
-        :create_container_image,
-        :update_container_image,
-        :create_environment,
-        :create_deployment
-      ]
-    end
-
-    def project_archived_rules
-      @project_archived_rules ||= [
-        :create_merge_request,
-        :push_code,
-        :push_code_to_protected_branches,
-        :update_merge_request,
-        :admin_merge_request
-      ]
-    end
-
-    def project_master_rules
-      @project_master_rules ||= project_dev_rules + [
-        :push_code_to_protected_branches,
-        :update_project_snippet,
-        :update_environment,
-        :update_deployment,
-        :admin_milestone,
-        :admin_project_snippet,
-        :admin_project_member,
-        :admin_merge_request,
-        :admin_note,
-        :admin_wiki,
-        :admin_project,
-        :admin_commit_status,
-        :admin_build,
-        :admin_container_image,
-        :admin_pipeline,
-        :admin_environment,
-        :admin_deployment
-      ]
-    end
-
-    def project_owner_rules
-      @project_owner_rules ||= project_master_rules + [
-        :change_namespace,
-        :change_visibility_level,
-        :rename_project,
-        :remove_project,
-        :archive_project,
-        :remove_fork_project,
-        :destroy_merge_request,
-        :destroy_issue
-      ]
-    end
-
-    def project_disabled_features_rules(project)
-      rules = []
-
-      unless project.issues_enabled
-        rules += named_abilities('issue')
-      end
-
-      unless project.merge_requests_enabled
-        rules += named_abilities('merge_request')
-      end
-
-      unless project.issues_enabled or project.merge_requests_enabled
-        rules += named_abilities('label')
-        rules += named_abilities('milestone')
-      end
-
-      unless project.snippets_enabled
-        rules += named_abilities('project_snippet')
-      end
-
-      unless project.wiki_enabled
-        rules += named_abilities('wiki')
-      end
-
-      unless project.builds_enabled
-        rules += named_abilities('build')
-        rules += named_abilities('pipeline')
-        rules += named_abilities('environment')
-        rules += named_abilities('deployment')
-      end
-
-      unless project.container_registry_enabled
-        rules += named_abilities('container_image')
-      end
-
-      rules
-    end
-
-    def group_abilities(user, group)
-      rules = []
-      rules << :read_group if can_read_group?(user, group)
-
-      owner = user.admin? || group.has_owner?(user)
-      master = owner || group.has_master?(user)
-
-      # Only group masters and group owners can create new projects
-      if master
-        rules += [
-          :create_projects,
-          :admin_milestones
-        ]
-      end
-
-      # Only group owner and administrators can admin group
-      if owner
-        rules += [
-          :admin_group,
-          :admin_namespace,
-          :admin_group_member,
-          :change_visibility_level
-        ]
-      end
-
-      if group.public? || (group.internal? && !user.external?)
-        rules << :request_access if group.request_access_enabled && group.users.exclude?(user)
-      end
-
-      rules.flatten
-    end
-
-    def can_read_group?(user, group)
-      return true if user.admin?
-      return true if group.public?
-      return true if group.internal? && !user.external?
-      return true if group.users.include?(user)
-
-      GroupProjectsFinder.new(group).execute(user).any?
-    end
-
+    # TODO: make this private and use the actual abilities stuff for this
     def can_edit_note?(user, note)
       return false if !note.editable? || !user.present?
       return true if note.author == user || user.admin?
@@ -426,207 +45,23 @@ class Ability
       end
     end
 
-    def namespace_abilities(user, namespace)
-      rules = []
-
-      # Only namespace owner and administrators can admin it
-      if namespace.owner == user || user.admin?
-        rules += [
-          :create_projects,
-          :admin_namespace
-        ]
-      end
-
-      rules.flatten
-    end
-
-    [:issue, :merge_request].each do |name|
-      define_method "#{name}_abilities" do |user, subject|
-        rules = []
-
-        if subject.author == user || (subject.respond_to?(:assignee) && subject.assignee == user)
-          rules += [
-            :"read_#{name}",
-            :"update_#{name}",
-          ]
-        end
-
-        rules += project_abilities(user, subject.project)
-        rules = filter_confidential_issues_abilities(user, subject, rules) if subject.is_a?(Issue)
-        rules
-      end
-    end
-
-    def note_abilities(user, note)
-      rules = []
-
-      if note.author == user
-        rules += [
-          :read_note,
-          :update_note,
-          :admin_note,
-          :resolve_note
-        ]
-      end
-
-      if note.respond_to?(:project) && note.project
-        rules += project_abilities(user, note.project)
-      end
-
-      if note.for_merge_request? && note.noteable.author == user
-        rules << :resolve_note
-      end
-
-      rules
-    end
-
-    def personal_snippet_abilities(user, snippet)
-      rules = []
-
-      if snippet.author == user
-        rules += [
-          :read_personal_snippet,
-          :update_personal_snippet,
-          :admin_personal_snippet
-        ]
-      end
-
-      if snippet.public? || (snippet.internal? && !user.external?)
-        rules << :read_personal_snippet
-      end
-
-      rules
+    def allowed?(user, action, subject)
+      allowed(user, subject).include?(action)
     end
 
-    def project_snippet_abilities(user, snippet)
-      rules = []
-
-      if snippet.author == user || user.admin?
-        rules += [
-          :read_project_snippet,
-          :update_project_snippet,
-          :admin_project_snippet
-        ]
-      end
-
-      if snippet.public? || (snippet.internal? && !user.external?) || (snippet.private? && snippet.project.team.member?(user))
-        rules << :read_project_snippet
-      end
-
-      rules
-    end
-
-    def group_member_abilities(user, subject)
-      rules = []
-      target_user = subject.user
-      group = subject.group
-
-      unless group.last_owner?(target_user)
-        can_manage = group_abilities(user, group).include?(:admin_group_member)
-
-        if can_manage
-          rules << :update_group_member
-          rules << :destroy_group_member
-        elsif user == target_user
-          rules << :destroy_group_member
-        end
-      end
-
-      rules
-    end
-
-    def project_member_abilities(user, subject)
-      rules = []
-      target_user = subject.user
-      project = subject.project
-
-      unless target_user == project.owner
-        can_manage = project_abilities(user, project).include?(:admin_project_member)
-
-        if can_manage
-          rules << :update_project_member
-          rules << :destroy_project_member
-        elsif user == target_user
-          rules << :destroy_project_member
-        end
-      end
-
-      rules
-    end
-
-    def commit_status_abilities(user, subject)
-      rules = project_abilities(user, subject.project)
-      # If subject is Ci::Build which inherits from CommitStatus filter the abilities
-      rules = filter_build_abilities(rules) if subject.is_a?(Ci::Build)
-      rules
-    end
-
-    def filter_build_abilities(rules)
-      # If we can't read build we should also not have that
-      # ability when looking at this in context of commit_status
-      %w(read create update admin).each do |rule|
-        rules.delete(:"#{rule}_commit_status") unless rules.include?(:"#{rule}_build")
-      end
-      rules
-    end
-
-    def runner_abilities(user, runner)
-      if user.is_admin?
-        [:assign_runner]
-      elsif runner.is_shared? || runner.locked?
-        []
-      elsif user.ci_authorized_runners.include?(runner)
-        [:assign_runner]
-      else
-        []
-      end
-    end
+    def allowed(user, subject)
+      return uncached_allowed(user, subject) unless RequestStore.active?
 
-    def user_abilities
-      [:read_user]
-    end
-
-    def abilities
-      @abilities ||= begin
-        abilities = Six.new
-        abilities << self
-        abilities
-      end
+      user_key = user ? user.id : 'anonymous'
+      subject_key = subject ? "#{subject.class.name}/#{subject.id}" : 'global'
+      key = "/ability/#{user_key}/#{subject_key}"
+      RequestStore[key] ||= uncached_allowed(user, subject).freeze
     end
 
     private
 
-    def restricted_public_level?
-      current_application_settings.restricted_visibility_levels.include?(Gitlab::VisibilityLevel::PUBLIC)
-    end
-
-    def named_abilities(name)
-      [
-        :"read_#{name}",
-        :"create_#{name}",
-        :"update_#{name}",
-        :"admin_#{name}"
-      ]
-    end
-
-    def filter_confidential_issues_abilities(user, issue, rules)
-      return rules if user.admin? || !issue.confidential?
-
-      unless issue.author == user || issue.assignee == user || issue.project.team.member?(user, Gitlab::Access::REPORTER)
-        rules.delete(:admin_issue)
-        rules.delete(:read_issue)
-        rules.delete(:update_issue)
-      end
-
-      rules
-    end
-
-    def project_group_member?(project, user)
-      project.group &&
-      (
-        project.group.members.exists?(user_id: user.id) ||
-        project.group.requesters.exists?(user_id: user.id)
-      )
+    def uncached_allowed(user, subject)
+      BasePolicy.class_for(subject).abilities(user, subject)
     end
   end
 end
diff --git a/app/models/application_setting.rb b/app/models/application_setting.rb
index f0bcb2d7cda..246477ffe88 100644
--- a/app/models/application_setting.rb
+++ b/app/models/application_setting.rb
@@ -146,7 +146,7 @@ class ApplicationSetting < ActiveRecord::Base
       default_project_visibility: Settings.gitlab.default_projects_features['visibility_level'],
       default_snippet_visibility: Settings.gitlab.default_projects_features['visibility_level'],
       domain_whitelist: Settings.gitlab['domain_whitelist'],
-      import_sources: %w[github bitbucket gitlab gitorious google_code fogbugz git gitlab_project],
+      import_sources: %w[github bitbucket gitlab google_code fogbugz git gitlab_project],
       shared_runners_enabled: Settings.gitlab_ci['shared_runners_enabled'],
       max_artifacts_size: Settings.artifacts['max_size'],
       require_two_factor_authentication: false,
diff --git a/app/models/ci/build.rb b/app/models/ci/build.rb
index 096b3b801af..61052437318 100644
--- a/app/models/ci/build.rb
+++ b/app/models/ci/build.rb
@@ -208,22 +208,31 @@ module Ci
       end
     end
 
+    def has_trace_file?
+      File.exist?(path_to_trace) || has_old_trace_file?
+    end
+
     def has_trace?
       raw_trace.present?
     end
 
     def raw_trace
-      if File.file?(path_to_trace)
-        File.read(path_to_trace)
-      elsif project.ci_id && File.file?(old_path_to_trace)
-        # Temporary fix for build trace data integrity
-        File.read(old_path_to_trace)
+      if File.exist?(trace_file_path)
+        File.read(trace_file_path)
       else
         # backward compatibility
         read_attribute :trace
       end
     end
 
+    ##
+    # Deprecated
+    #
+    # This is a hotfix for CI build data integrity, see #4246
+    def has_old_trace_file?
+      project.ci_id && File.exist?(old_path_to_trace)
+    end
+
     def trace
       trace = raw_trace
       if project && trace.present? && project.runners_token.present?
@@ -262,6 +271,14 @@ module Ci
       end
     end
 
+    def trace_file_path
+      if has_old_trace_file?
+        old_path_to_trace
+      else
+        path_to_trace
+      end
+    end
+
     def dir_to_trace
       File.join(
         Settings.gitlab_ci.builds_path,
@@ -352,7 +369,7 @@ module Ci
     end
 
     def artifacts?
-      !artifacts_expired? && artifacts_file.exists?
+      !artifacts_expired? && self[:artifacts_file].present?
     end
 
     def artifacts_metadata?
diff --git a/app/models/ci/pipeline.rb b/app/models/ci/pipeline.rb
index 087abe4cbb1..bd1737c7587 100644
--- a/app/models/ci/pipeline.rb
+++ b/app/models/ci/pipeline.rb
@@ -1,7 +1,7 @@
 module Ci
   class Pipeline < ActiveRecord::Base
     extend Ci::Model
-    include Statuseable
+    include HasStatus
 
     self.table_name = 'ci_commits'
 
@@ -65,8 +65,8 @@ module Ci
     end
 
     # ref can't be HEAD or SHA, can only be branch/tag name
-    scope :latest_successful_for, ->(ref = default_branch) do
-      where(ref: ref).success.order(id: :desc).limit(1)
+    def self.latest_successful_for(ref)
+      where(ref: ref).order(id: :desc).success.first
     end
 
     def self.truncate_sha(sha)
@@ -83,7 +83,7 @@ module Ci
     end
 
     def stages_with_latest_statuses
-      statuses.latest.order(:stage_idx).group_by(&:stage)
+      statuses.latest.includes(project: :namespace).order(:stage_idx).group_by(&:stage)
     end
 
     def project_id
diff --git a/app/models/commit.rb b/app/models/commit.rb
index 817d063e4a2..e64fd1e0c1b 100644
--- a/app/models/commit.rb
+++ b/app/models/commit.rb
@@ -108,15 +108,6 @@ class Commit
     @diff_line_count
   end
 
-  # Returns a string describing the commit for use in a link title
-  #
-  # Example
-  #
-  #   "Commit: Alex Denisov - Project git clone panel"
-  def link_title
-    "Commit: #{author_name} - #{title}"
-  end
-
   # Returns the commits title.
   #
   # Usually, the commit title is the first line of the commit message.
diff --git a/app/models/commit_range.rb b/app/models/commit_range.rb
index 630ee9601e0..656a242c265 100644
--- a/app/models/commit_range.rb
+++ b/app/models/commit_range.rb
@@ -4,12 +4,10 @@
 #
 #   range = CommitRange.new('f3f85602...e86e1013', project)
 #   range.exclude_start?  # => false
-#   range.reference_title # => "Commits f3f85602 through e86e1013"
 #   range.to_s            # => "f3f85602...e86e1013"
 #
 #   range = CommitRange.new('f3f856029bc5f966c5a7ee24cf7efefdd20e6019..e86e1013709735be5bb767e2b228930c543f25ae', project)
 #   range.exclude_start?  # => true
-#   range.reference_title # => "Commits f3f85602^ through e86e1013"
 #   range.to_param        # => {from: "f3f856029bc5f966c5a7ee24cf7efefdd20e6019^", to: "e86e1013709735be5bb767e2b228930c543f25ae"}
 #   range.to_s            # => "f3f85602..e86e1013"
 #
@@ -109,11 +107,6 @@ class CommitRange
     reference
   end
 
-  # Returns a String for use in a link's title attribute
-  def reference_title
-    "Commits #{sha_start} through #{sha_to}"
-  end
-
   # Return a Hash of parameters for passing to a URL helper
   #
   # See `namespace_project_compare_url`
diff --git a/app/models/commit_status.rb b/app/models/commit_status.rb
index 84ceeac7d3e..4a628924499 100644
--- a/app/models/commit_status.rb
+++ b/app/models/commit_status.rb
@@ -1,5 +1,5 @@
 class CommitStatus < ActiveRecord::Base
-  include Statuseable
+  include HasStatus
   include Importable
 
   self.table_name = 'ci_builds'
@@ -25,6 +25,8 @@ class CommitStatus < ActiveRecord::Base
   scope :retried, -> { where.not(id: latest) }
   scope :ordered, -> { order(:name) }
   scope :ignored, -> { where(allow_failure: true, status: [:failed, :canceled]) }
+  scope :latest_ci_stages, -> { latest.ordered.includes(project: :namespace) }
+  scope :retried_ci_stages, -> { retried.ordered.includes(project: :namespace) }
 
   state_machine :status do
     event :enqueue do
diff --git a/app/models/concerns/awardable.rb b/app/models/concerns/awardable.rb
index 800a16ab246..d8d4575bb4d 100644
--- a/app/models/concerns/awardable.rb
+++ b/app/models/concerns/awardable.rb
@@ -2,7 +2,7 @@ module Awardable
   extend ActiveSupport::Concern
 
   included do
-    has_many :award_emoji, -> { includes(:user) }, as: :awardable, dependent: :destroy
+    has_many :award_emoji, -> { includes(:user).order(:id) }, as: :awardable, dependent: :destroy
 
     if self < Participable
       # By default we always load award_emoji user association
@@ -59,6 +59,18 @@ module Awardable
     true
   end
 
+  def awardable_votes?(name)
+    AwardEmoji::UPVOTE_NAME == name || AwardEmoji::DOWNVOTE_NAME == name
+  end
+
+  def user_can_award?(current_user, name)
+    if user_authored?(current_user)
+      !awardable_votes?(normalize_name(name))
+    else
+      true
+    end
+  end
+
   def awarded_emoji?(emoji_name, current_user)
     award_emoji.where(name: emoji_name, user: current_user).exists?
   end
diff --git a/app/models/concerns/statuseable.rb b/app/models/concerns/has_status.rb
index 750f937b724..f7b8352405c 100644
--- a/app/models/concerns/statuseable.rb
+++ b/app/models/concerns/has_status.rb
@@ -1,4 +1,4 @@
-module Statuseable
+module HasStatus
   extend ActiveSupport::Concern
 
   AVAILABLE_STATUSES = %w[created pending running success failed canceled skipped]
diff --git a/app/models/concerns/issuable.rb b/app/models/concerns/issuable.rb
index 8e11d4f57cf..22231b2e0f0 100644
--- a/app/models/concerns/issuable.rb
+++ b/app/models/concerns/issuable.rb
@@ -196,6 +196,10 @@ module Issuable
     end
   end
 
+  def user_authored?(user)
+    user == author
+  end
+
   def subscribed_without_subscriptions?(user)
     participants(user).include?(user)
   end
diff --git a/app/models/concerns/note_on_diff.rb b/app/models/concerns/note_on_diff.rb
index a881fb83b7f..b8dd27a7afe 100644
--- a/app/models/concerns/note_on_diff.rb
+++ b/app/models/concerns/note_on_diff.rb
@@ -28,4 +28,8 @@ module NoteOnDiff
   def can_be_award_emoji?
     false
   end
+
+  def to_discussion
+    Discussion.new([self])
+  end
 end
diff --git a/app/models/concerns/project_features_compatibility.rb b/app/models/concerns/project_features_compatibility.rb
new file mode 100644
index 00000000000..9216122923e
--- /dev/null
+++ b/app/models/concerns/project_features_compatibility.rb
@@ -0,0 +1,37 @@
+# Makes api V3 compatible with old project features permissions methods
+#
+# After migrating issues_enabled merge_requests_enabled builds_enabled snippets_enabled and wiki_enabled
+# fields to a new table "project_features", support for the old fields is still needed in the API.
+
+module ProjectFeaturesCompatibility
+  extend ActiveSupport::Concern
+
+  def wiki_enabled=(value)
+    write_feature_attribute(:wiki_access_level, value)
+  end
+
+  def builds_enabled=(value)
+    write_feature_attribute(:builds_access_level, value)
+  end
+
+  def merge_requests_enabled=(value)
+    write_feature_attribute(:merge_requests_access_level, value)
+  end
+
+  def issues_enabled=(value)
+    write_feature_attribute(:issues_access_level, value)
+  end
+
+  def snippets_enabled=(value)
+    write_feature_attribute(:snippets_access_level, value)
+  end
+
+  private
+
+  def write_feature_attribute(field, value)
+    build_project_feature unless project_feature
+
+    access_level = value == "true" ? ProjectFeature::ENABLED : ProjectFeature::DISABLED
+    project_feature.update_attribute(field, access_level)
+  end
+end
diff --git a/app/models/concerns/taskable.rb b/app/models/concerns/taskable.rb
index df2a9e3e84b..a3ac577cf3e 100644
--- a/app/models/concerns/taskable.rb
+++ b/app/models/concerns/taskable.rb
@@ -52,11 +52,11 @@ module Taskable
   end
 
   # Return a string that describes the current state of this Taskable's task
-  # list items, e.g. "20 tasks (12 completed, 8 remaining)"
+  # list items, e.g. "12 of 20 tasks completed"
   def task_status
     return '' if description.blank?
 
     sum = tasks.summary
-    "#{sum.item_count} tasks (#{sum.complete_count} completed, #{sum.incomplete_count} remaining)"
+    "#{sum.complete_count} of #{sum.item_count} #{'task'.pluralize(sum.item_count)} completed"
   end
 end
diff --git a/app/models/diff_note.rb b/app/models/diff_note.rb
index c8320ff87fa..4442cefc7e9 100644
--- a/app/models/diff_note.rb
+++ b/app/models/diff_note.rb
@@ -107,10 +107,6 @@ class DiffNote < Note
     self.noteable.find_diff_discussion(self.discussion_id)
   end
 
-  def to_discussion
-    Discussion.new([self])
-  end
-
   private
 
   def supported?
diff --git a/app/models/event.rb b/app/models/event.rb
index fd736d12359..a0b7b0dc2b5 100644
--- a/app/models/event.rb
+++ b/app/models/event.rb
@@ -65,7 +65,7 @@ class Event < ActiveRecord::Base
     elsif created_project?
       true
     elsif issue? || issue_note?
-      Ability.abilities.allowed?(user, :read_issue, note? ? note_target : target)
+      Ability.allowed?(user, :read_issue, note? ? note_target : target)
     else
       ((merge_request? || note?) && target.present?) || milestone?
     end
diff --git a/app/models/merge_request.rb b/app/models/merge_request.rb
index 5330a07ee35..b0b1313f94a 100644
--- a/app/models/merge_request.rb
+++ b/app/models/merge_request.rb
@@ -10,14 +10,16 @@ class MergeRequest < ActiveRecord::Base
   belongs_to :source_project, foreign_key: :source_project_id, class_name: "Project"
   belongs_to :merge_user, class_name: "User"
 
-  has_one :merge_request_diff, dependent: :destroy
+  has_many :merge_request_diffs, dependent: :destroy
+  has_one :merge_request_diff,
+    -> { order('merge_request_diffs.id DESC') }
 
   has_many :events, as: :target, dependent: :destroy
 
   serialize :merge_params, Hash
 
-  after_create :create_merge_request_diff, unless: :importing?
-  after_update :update_merge_request_diff
+  after_create :ensure_merge_request_diff, unless: :importing?
+  after_update :reload_diff_if_branch_changed
 
   delegate :commits, :real_size, to: :merge_request_diff, prefix: nil
 
@@ -89,13 +91,13 @@ class MergeRequest < ActiveRecord::Base
     end
   end
 
-  validates :source_project, presence: true, unless: [:allow_broken, :importing?]
+  validates :source_project, presence: true, unless: [:allow_broken, :importing?, :closed_without_fork?]
   validates :source_branch, presence: true
   validates :target_project, presence: true
   validates :target_branch, presence: true
   validates :merge_user, presence: true, if: :merge_when_build_succeeds?
-  validate :validate_branches, unless: [:allow_broken, :importing?]
-  validate :validate_fork
+  validate :validate_branches, unless: [:allow_broken, :importing?, :closed_without_fork?]
+  validate :validate_fork, unless: :closed_without_fork?
 
   scope :by_branch, ->(branch_name) { where("(source_branch LIKE :branch) OR (target_branch LIKE :branch)", branch: branch_name) }
   scope :cared, ->(user) { where('assignee_id = :user OR author_id = :user', user: user.id) }
@@ -170,10 +172,10 @@ class MergeRequest < ActiveRecord::Base
   end
 
   def diffs(diff_options = nil)
-    if self.compare
-      self.compare.diffs(diff_options)
+    if compare
+      compare.diffs(diff_options)
     else
-      Gitlab::Diff::FileCollection::MergeRequest.new(self, diff_options: diff_options)
+      merge_request_diff.diffs(diff_options)
     end
   end
 
@@ -184,8 +186,8 @@ class MergeRequest < ActiveRecord::Base
   def diff_base_commit
     if persisted?
       merge_request_diff.base_commit
-    elsif diff_start_commit && diff_head_commit
-      self.target_project.merge_base_commit(diff_start_sha, diff_head_sha)
+    else
+      branch_merge_base_commit
     end
   end
 
@@ -238,12 +240,21 @@ class MergeRequest < ActiveRecord::Base
 
   def source_branch_head
     source_branch_ref = @source_branch_sha || source_branch
-    source_project.repository.commit(source_branch) if source_branch_ref
+    source_project.repository.commit(source_branch_ref) if source_branch_ref
   end
 
   def target_branch_head
     target_branch_ref = @target_branch_sha || target_branch
-    target_project.repository.commit(target_branch) if target_branch_ref
+    target_project.repository.commit(target_branch_ref) if target_branch_ref
+  end
+
+  def branch_merge_base_commit
+    start_sha = target_branch_sha
+    head_sha  = source_branch_sha
+
+    if start_sha && head_sha
+      target_project.merge_base_commit(start_sha, head_sha)
+    end
   end
 
   def target_branch_sha
@@ -267,16 +278,16 @@ class MergeRequest < ActiveRecord::Base
   # Return diff_refs instance trying to not touch the git repository
   def diff_sha_refs
     if merge_request_diff && merge_request_diff.diff_refs_by_sha?
-      return Gitlab::Diff::DiffRefs.new(
-        base_sha:  merge_request_diff.base_commit_sha,
-        start_sha: merge_request_diff.start_commit_sha,
-        head_sha:  merge_request_diff.head_commit_sha
-      )
+      merge_request_diff.diff_refs
     else
       diff_refs
     end
   end
 
+  def branch_merge_base_sha
+    branch_merge_base_commit.try(:sha)
+  end
+
   def validate_branches
     if target_project == source_project && target_branch == source_branch
       errors.add :branch_conflict, "You can not use same project/branch for source and target"
@@ -294,36 +305,49 @@ class MergeRequest < ActiveRecord::Base
 
   def validate_fork
     return true unless target_project && source_project
+    return true if target_project == source_project
+    return true unless forked_source_project_missing?
 
-    if target_project == source_project
-      true
-    else
-      # If source and target projects are different
-      # we should check if source project is actually a fork of target project
-      if source_project.forked_from?(target_project)
-        true
-      else
-        errors.add :validate_fork,
-                   'Source project is not a fork of target project'
-      end
-    end
+    errors.add :validate_fork,
+               'Source project is not a fork of the target project'
   end
 
-  def update_merge_request_diff
+  def closed_without_fork?
+    closed? && forked_source_project_missing?
+  end
+
+  def forked_source_project_missing?
+    return false unless for_fork?
+    return true unless source_project
+
+    !source_project.forked_from?(target_project)
+  end
+
+  def ensure_merge_request_diff
+    merge_request_diff || create_merge_request_diff
+  end
+
+  def create_merge_request_diff
+    merge_request_diffs.create
+    reload_merge_request_diff
+  end
+
+  def reload_merge_request_diff
+    merge_request_diff(true)
+  end
+
+  def reload_diff_if_branch_changed
     if source_branch_changed? || target_branch_changed?
       reload_diff
     end
   end
 
   def reload_diff
-    return unless merge_request_diff && open?
+    return unless open?
 
     old_diff_refs = self.diff_refs
-
-    merge_request_diff.reload_content
-
+    create_merge_request_diff
     MergeRequests::MergeRequestDiffCacheService.new.execute(self)
-
     new_diff_refs = self.diff_refs
 
     update_diff_notes_positions(
@@ -387,7 +411,7 @@ class MergeRequest < ActiveRecord::Base
   def can_remove_source_branch?(current_user)
     !source_project.protected_branch?(source_branch) &&
       !source_project.root_ref?(source_branch) &&
-      Ability.abilities.allowed?(current_user, :push_code, source_project) &&
+      Ability.allowed?(current_user, :push_code, source_project) &&
       diff_head_commit == source_branch_head
   end
 
@@ -705,7 +729,9 @@ class MergeRequest < ActiveRecord::Base
   end
 
   def pipeline
-    @pipeline ||= source_project.pipeline(diff_head_sha, source_branch) if diff_head_sha && source_project
+    return unless diff_head_sha && source_project
+
+    @pipeline ||= source_project.pipeline_for(source_branch, diff_head_sha)
   end
 
   def all_pipelines
@@ -777,8 +803,12 @@ class MergeRequest < ActiveRecord::Base
     return @conflicts_can_be_resolved_in_ui = false unless has_complete_diff_refs?
 
     begin
-      @conflicts_can_be_resolved_in_ui = conflicts.files.each(&:lines)
-    rescue Gitlab::Conflict::Parser::ParserError, Gitlab::Conflict::FileCollection::ConflictSideMissing
+      # Try to parse each conflict. If the MR's mergeable status hasn't been updated,
+      # ensure that we don't say there are conflicts to resolve when there are no conflict
+      # files.
+      conflicts.files.each(&:lines)
+      @conflicts_can_be_resolved_in_ui = conflicts.files.length > 0
+    rescue Rugged::OdbError, Gitlab::Conflict::Parser::ParserError, Gitlab::Conflict::FileCollection::ConflictSideMissing
       @conflicts_can_be_resolved_in_ui = false
     end
   end
diff --git a/app/models/merge_request_diff.rb b/app/models/merge_request_diff.rb
index 32cc6a3bfea..445179a4487 100644
--- a/app/models/merge_request_diff.rb
+++ b/app/models/merge_request_diff.rb
@@ -8,8 +8,6 @@ class MergeRequestDiff < ActiveRecord::Base
 
   belongs_to :merge_request
 
-  delegate :source_branch_sha, :target_branch_sha, :target_branch, :source_branch, to: :merge_request, prefix: nil
-
   state_machine :state, initial: :empty do
     state :collected
     state :overflow
@@ -24,12 +22,47 @@ class MergeRequestDiff < ActiveRecord::Base
   serialize :st_commits
   serialize :st_diffs
 
-  after_create :reload_content, unless: :importing?
-  after_save :keep_around_commits, unless: :importing?
+  # All diff information is collected from repository after object is created.
+  # It allows you to override variables like head_commit_sha before getting diff.
+  after_create :save_git_content, unless: :importing?
+
+  def self.select_without_diff
+    select(column_names - ['st_diffs'])
+  end
 
-  def reload_content
+  # Collect information about commits and diff from repository
+  # and save it to the database as serialized data
+  def save_git_content
+    ensure_commits_sha
+    save_commits
     reload_commits
-    reload_diffs
+    save_diffs
+    keep_around_commits
+  end
+
+  def ensure_commits_sha
+    merge_request.fetch_ref
+    self.start_commit_sha ||= merge_request.target_branch_sha
+    self.head_commit_sha  ||= merge_request.source_branch_sha
+    self.base_commit_sha  ||= find_base_sha
+    save
+  end
+
+  # Override head_commit_sha to keep compatibility with merge request diff
+  # created before version 8.4 that does not store head_commit_sha in separate db field.
+  def head_commit_sha
+    if persisted? && super.nil?
+      last_commit.try(:sha)
+    else
+      super
+    end
+  end
+
+  # This method will rely on repository branch sha
+  # in case start_commit_sha is nil. Its necesarry for old merge request diff
+  # created before version 8.4 to work
+  def safe_start_commit_sha
+    start_commit_sha || merge_request.target_branch_sha
   end
 
   def size
@@ -38,14 +71,11 @@ class MergeRequestDiff < ActiveRecord::Base
 
   def raw_diffs(options = {})
     if options[:ignore_whitespace_change]
-      @raw_diffs_no_whitespace ||= begin
-        compare = Gitlab::Git::Compare.new(
+      @diffs_no_whitespace ||=
+        Gitlab::Git::Compare.new(
           repository.raw_repository,
-          self.start_commit_sha || self.target_branch_sha,
-          self.head_commit_sha || self.source_branch_sha,
-        )
-        compare.diffs(options)
-      end
+          safe_start_commit_sha,
+          head_commit_sha).diffs(options)
     else
       @raw_diffs ||= {}
       @raw_diffs[options] ||= load_diffs(st_diffs, options)
@@ -56,6 +86,11 @@ class MergeRequestDiff < ActiveRecord::Base
     @commits ||= load_commits(st_commits || [])
   end
 
+  def reload_commits
+    @commits = nil
+    commits
+  end
+
   def last_commit
     commits.first
   end
@@ -65,55 +100,60 @@ class MergeRequestDiff < ActiveRecord::Base
   end
 
   def base_commit
-    return unless self.base_commit_sha
+    return unless base_commit_sha
 
-    project.commit(self.base_commit_sha)
+    project.commit(base_commit_sha)
   end
 
   def start_commit
-    return unless self.start_commit_sha
+    return unless start_commit_sha
 
-    project.commit(self.start_commit_sha)
+    project.commit(start_commit_sha)
   end
 
   def head_commit
-    return last_commit unless self.head_commit_sha
+    return unless head_commit_sha
+
+    project.commit(head_commit_sha)
+  end
+
+  def diff_refs
+    return unless start_commit_sha || base_commit_sha
 
-    project.commit(self.head_commit_sha)
+    Gitlab::Diff::DiffRefs.new(
+      base_sha:  base_commit_sha,
+      start_sha: start_commit_sha,
+      head_sha:  head_commit_sha
+    )
   end
 
   def diff_refs_by_sha?
     base_commit_sha? && head_commit_sha? && start_commit_sha?
   end
 
+  def diffs(diff_options = nil)
+    Gitlab::Diff::FileCollection::MergeRequestDiff.new(self, diff_options: diff_options)
+  end
+
+  def project
+    merge_request.target_project
+  end
+
   def compare
     @compare ||=
-      begin
-        # Update ref for merge request
-        merge_request.fetch_ref
+      Gitlab::Git::Compare.new(
+        repository.raw_repository,
+        safe_start_commit_sha,
+        head_commit_sha
+      )
+  end
 
-        Gitlab::Git::Compare.new(
-          repository.raw_repository,
-          self.target_branch_sha,
-          self.source_branch_sha
-        )
-      end
+  def latest?
+    self == merge_request.merge_request_diff
   end
 
   private
 
-  # Collect array of Git::Commit objects
-  # between target and source branches
-  def unmerged_commits
-    commits = compare.commits
-
-    if commits.present?
-      commits = Commit.decorate(commits, merge_request.source_project).reverse
-    end
-
-    commits
-  end
-
   def dump_commits(commits)
     commits.map(&:to_hash)
   end
@@ -122,26 +162,21 @@ class MergeRequestDiff < ActiveRecord::Base
     array.map { |hash| Commit.new(Gitlab::Git::Commit.new(hash), merge_request.source_project) }
   end
 
-  # Reload all commits related to current merge request from repo
+  # Load all commits related to current merge request diff from repo
   # and save it as array of hashes in st_commits db field
-  def reload_commits
+  def save_commits
     new_attributes = {}
 
-    commit_objects = unmerged_commits
+    commits = compare.commits
 
-    if commit_objects.present?
-      new_attributes[:st_commits] = dump_commits(commit_objects)
+    if commits.present?
+      commits = Commit.decorate(commits, merge_request.source_project).reverse
+      new_attributes[:st_commits] = dump_commits(commits)
     end
 
     update_columns_serialized(new_attributes)
   end
 
-  # Collect array of Git::Diff objects
-  # between target and source branches
-  def unmerged_diffs
-    compare.diffs(Commit.max_diff_options)
-  end
-
   def dump_diffs(diffs)
     if diffs.respond_to?(:map)
       diffs.map(&:to_hash)
@@ -162,16 +197,16 @@ class MergeRequestDiff < ActiveRecord::Base
     end
   end
 
-  # Reload diffs between branches related to current merge request from repo
+  # Load diffs between branches related to current merge request diff from repo
   # and save it as array of hashes in st_diffs db field
-  def reload_diffs
+  def save_diffs
     new_attributes = {}
     new_diffs = []
 
     if commits.size.zero?
       new_attributes[:state] = :empty
     else
-      diff_collection = unmerged_diffs
+      diff_collection = compare.diffs(Commit.max_diff_options)
 
       if diff_collection.overflow?
         # Set our state to 'overflow' to make the #empty? and #collected?
@@ -188,32 +223,17 @@ class MergeRequestDiff < ActiveRecord::Base
     end
 
     new_attributes[:st_diffs] = new_diffs
-
-    new_attributes[:start_commit_sha] = self.target_branch_sha
-    new_attributes[:head_commit_sha] = self.source_branch_sha
-    new_attributes[:base_commit_sha] = branch_base_sha
-
     update_columns_serialized(new_attributes)
-
-    keep_around_commits
-  end
-
-  def project
-    merge_request.target_project
   end
 
   def repository
     project.repository
   end
 
-  def branch_base_commit
-    return unless self.source_branch_sha && self.target_branch_sha
-
-    project.merge_base_commit(self.source_branch_sha, self.target_branch_sha)
-  end
+  def find_base_sha
+    return unless head_commit_sha && start_commit_sha
 
-  def branch_base_sha
-    branch_base_commit.try(:sha)
+    project.merge_base_commit(head_commit_sha, start_commit_sha).try(:sha)
   end
 
   def utf8_st_diffs
@@ -248,8 +268,8 @@ class MergeRequestDiff < ActiveRecord::Base
   end
 
   def keep_around_commits
-    repository.keep_around(target_branch_sha)
-    repository.keep_around(source_branch_sha)
-    repository.keep_around(branch_base_sha)
+    repository.keep_around(start_commit_sha)
+    repository.keep_around(head_commit_sha)
+    repository.keep_around(base_commit_sha)
   end
 end
diff --git a/app/models/note.rb b/app/models/note.rb
index f2656df028b..b94e3cff2ce 100644
--- a/app/models/note.rb
+++ b/app/models/note.rb
@@ -223,6 +223,10 @@ class Note < ActiveRecord::Base
     end
   end
 
+  def user_authored?(user)
+    user == author
+  end
+
   def award_emoji?
     can_be_award_emoji? && contains_emoji_only?
   end
diff --git a/app/models/project.rb b/app/models/project.rb
index 8cf093be4c3..a6de2c48071 100644
--- a/app/models/project.rb
+++ b/app/models/project.rb
@@ -11,24 +11,23 @@ class Project < ActiveRecord::Base
   include AfterCommitQueue
   include CaseSensitivity
   include TokenAuthenticatable
+  include ProjectFeaturesCompatibility
 
   extend Gitlab::ConfigHelper
 
   UNKNOWN_IMPORT_URL = 'http://unknown.git'
 
+  delegate :feature_available?, :builds_enabled?, :wiki_enabled?, :merge_requests_enabled?, to: :project_feature, allow_nil: true
+
   default_value_for :archived, false
   default_value_for :visibility_level, gitlab_config_features.visibility_level
-  default_value_for :issues_enabled, gitlab_config_features.issues
-  default_value_for :merge_requests_enabled, gitlab_config_features.merge_requests
-  default_value_for :builds_enabled, gitlab_config_features.builds
-  default_value_for :wiki_enabled, gitlab_config_features.wiki
-  default_value_for :snippets_enabled, gitlab_config_features.snippets
   default_value_for :container_registry_enabled, gitlab_config_features.container_registry
   default_value_for(:repository_storage) { current_application_settings.repository_storage }
   default_value_for(:shared_runners_enabled) { current_application_settings.shared_runners_enabled }
 
   after_create :ensure_dir_exist
   after_save :ensure_dir_exist, if: :namespace_id_changed?
+  after_initialize :setup_project_feature
 
   # set last_activity_at to the same as created_at
   after_create :set_last_activity_at
@@ -62,10 +61,10 @@ class Project < ActiveRecord::Base
   belongs_to :group, -> { where(type: Group) }, foreign_key: 'namespace_id'
   belongs_to :namespace
 
-  has_one :board, dependent: :destroy
-
   has_one :last_event, -> {order 'events.created_at DESC'}, class_name: 'Event', foreign_key: 'project_id'
 
+  has_one :board, dependent: :destroy
+
   # Project services
   has_many :services
   has_one :campfire_service, dependent: :destroy
@@ -130,6 +129,7 @@ class Project < ActiveRecord::Base
   has_many :notification_settings, dependent: :destroy, as: :source
 
   has_one :import_data, dependent: :destroy, class_name: "ProjectImportData"
+  has_one :project_feature, dependent: :destroy
 
   has_many :commit_statuses, dependent: :destroy, class_name: 'CommitStatus', foreign_key: :gl_project_id
   has_many :pipelines, dependent: :destroy, class_name: 'Ci::Pipeline', foreign_key: :gl_project_id
@@ -142,6 +142,7 @@ class Project < ActiveRecord::Base
   has_many :deployments, dependent: :destroy
 
   accepts_nested_attributes_for :variables, allow_destroy: true
+  accepts_nested_attributes_for :project_feature
 
   delegate :name, to: :owner, allow_nil: true, prefix: true
   delegate :members, to: :team, prefix: true
@@ -159,8 +160,6 @@ class Project < ActiveRecord::Base
     length: { within: 0..255 },
     format: { with: Gitlab::Regex.project_path_regex,
               message: Gitlab::Regex.project_path_regex_message }
-  validates :issues_enabled, :merge_requests_enabled,
-            :wiki_enabled, inclusion: { in: [true, false] }
   validates :namespace, presence: true
   validates_uniqueness_of :name, scope: :namespace_id
   validates_uniqueness_of :path, scope: :namespace_id
@@ -196,6 +195,9 @@ class Project < ActiveRecord::Base
   scope :for_milestones, ->(ids) { joins(:milestones).where('milestones.id' => ids).distinct }
   scope :with_push, -> { joins(:events).where('events.action = ?', Event::PUSHED) }
 
+  scope :with_builds_enabled, -> { joins('LEFT JOIN project_features ON projects.id = project_features.project_id').where('project_features.builds_access_level IS NULL or project_features.builds_access_level > 0') }
+  scope :with_issues_enabled, -> { joins('LEFT JOIN project_features ON projects.id = project_features.project_id').where('project_features.issues_access_level IS NULL or project_features.issues_access_level > 0') }
+
   scope :active, -> { joins(:issues, :notes, :merge_requests).order('issues.created_at, notes.created_at, merge_requests.created_at DESC') }
   scope :abandoned, -> { where('projects.last_activity_at < ?', 6.months.ago) }
 
@@ -390,6 +392,13 @@ class Project < ActiveRecord::Base
     end
   end
 
+  def lfs_enabled?
+    return false unless Gitlab.config.lfs.enabled
+    return Gitlab.config.lfs.enabled if self[:lfs_enabled].nil?
+
+    self[:lfs_enabled]
+  end
+
   def repository_storage_path
     Gitlab.config.repositories.storages[repository_storage]
   end
@@ -436,7 +445,7 @@ class Project < ActiveRecord::Base
 
   # ref can't be HEAD, can only be branch/tag name or SHA
   def latest_successful_builds_for(ref = default_branch)
-    latest_pipeline = pipelines.latest_successful_for(ref).first
+    latest_pipeline = pipelines.latest_successful_for(ref)
 
     if latest_pipeline
       latest_pipeline.builds.latest.with_artifacts
@@ -680,6 +689,10 @@ class Project < ActiveRecord::Base
     update_column(:has_external_issue_tracker, services.external_issue_trackers.any?)
   end
 
+  def has_wiki?
+    wiki_enabled? || has_external_wiki?
+  end
+
   def external_wiki
     if has_external_wiki.nil?
       cache_has_external_wiki # Populate
@@ -1035,6 +1048,7 @@ class Project < ActiveRecord::Base
                                         "refs/heads/#{branch}",
                                         force: true)
     repository.copy_gitattributes(branch)
+    repository.expire_avatar_cache(branch)
     reload_default_branch
   end
 
@@ -1095,16 +1109,21 @@ class Project < ActiveRecord::Base
     !namespace.share_with_group_lock
   end
 
-  def pipeline(sha, ref)
+  def pipeline_for(ref, sha = nil)
+    sha ||= commit(ref).try(:sha)
+
+    return unless sha
+
     pipelines.order(id: :desc).find_by(sha: sha, ref: ref)
   end
 
-  def ensure_pipeline(sha, ref, current_user = nil)
-    pipeline(sha, ref) || pipelines.create(sha: sha, ref: ref, user: current_user)
+  def ensure_pipeline(ref, sha, current_user = nil)
+    pipeline_for(ref, sha) ||
+      pipelines.create(sha: sha, ref: ref, user: current_user)
   end
 
   def enable_ci
-    self.builds_enabled = true
+    project_feature.update_attribute(:builds_access_level, ProjectFeature::ENABLED)
   end
 
   def any_runners?(&block)
@@ -1271,6 +1290,11 @@ class Project < ActiveRecord::Base
 
   private
 
+  # Prevents the creation of project_feature record for every project
+  def setup_project_feature
+    build_project_feature unless project_feature
+  end
+
   def default_branch_protected?
     current_application_settings.default_branch_protection == Gitlab::Access::PROTECTION_FULL ||
       current_application_settings.default_branch_protection == Gitlab::Access::PROTECTION_DEV_CAN_MERGE
diff --git a/app/models/project_feature.rb b/app/models/project_feature.rb
new file mode 100644
index 00000000000..9c602c582bd
--- /dev/null
+++ b/app/models/project_feature.rb
@@ -0,0 +1,63 @@
+class ProjectFeature < ActiveRecord::Base
+  # == Project features permissions
+  #
+  # Grants access level to project tools
+  #
+  # Tools can be enabled only for users, everyone or disabled
+  # Access control is made only for non private projects
+  #
+  # levels:
+  #
+  # Disabled: not enabled for anyone
+  # Private:  enabled only for team members
+  # Enabled:  enabled for everyone able to access the project
+  #
+
+  # Permision levels
+  DISABLED = 0
+  PRIVATE  = 10
+  ENABLED  = 20
+
+  FEATURES = %i(issues merge_requests wiki snippets builds)
+
+  belongs_to :project
+
+  def feature_available?(feature, user)
+    raise ArgumentError, 'invalid project feature' unless FEATURES.include?(feature)
+
+    get_permission(user, public_send("#{feature}_access_level"))
+  end
+
+  def builds_enabled?
+    return true unless builds_access_level
+
+    builds_access_level > DISABLED
+  end
+
+  def wiki_enabled?
+    return true unless wiki_access_level
+
+    wiki_access_level > DISABLED
+  end
+
+  def merge_requests_enabled?
+    return true unless merge_requests_access_level
+
+    merge_requests_access_level > DISABLED
+  end
+
+  private
+
+  def get_permission(user, level)
+    case level
+    when DISABLED
+      false
+    when PRIVATE
+      user && (project.team.member?(user) || user.admin?)
+    when ENABLED
+      true
+    else
+      true
+    end
+  end
+end
diff --git a/app/models/repository.rb b/app/models/repository.rb
index bdc3b9d1c1c..f891e8374d2 100644
--- a/app/models/repository.rb
+++ b/app/models/repository.rb
@@ -120,8 +120,21 @@ class Repository
     commits
   end
 
-  def find_branch(name)
-    raw_repository.branches.find { |branch| branch.name == name }
+  def find_branch(name, fresh_repo: true)
+    # Since the Repository object may have in-memory index changes, invalidating the memoized Repository object may
+    # cause unintended side effects. Because finding a branch is a read-only operation, we can safely instantiate
+    # a new repo here to ensure a consistent state to avoid a libgit2 bug where concurrent access (e.g. via git gc)
+    # may cause the branch to "disappear" erroneously or have the wrong SHA.
+    #
+    # See: https://github.com/libgit2/libgit2/issues/1534 and https://gitlab.com/gitlab-org/gitlab-ce/issues/15392
+    raw_repo =
+      if fresh_repo
+        Gitlab::Git::Repository.new(path_to_repo)
+      else
+        raw_repository
+      end
+
+    raw_repo.find_branch(name)
   end
 
   def find_tag(name)
@@ -1065,7 +1078,7 @@ class Repository
 
     @avatar ||= cache.fetch(:avatar) do
       AVATAR_FILES.find do |file|
-        blob_at_branch('master', file)
+        blob_at_branch(root_ref, file)
       end
     end
   end
diff --git a/app/models/user.rb b/app/models/user.rb
index ad3cfbc03e4..6996740eebd 100644
--- a/app/models/user.rb
+++ b/app/models/user.rb
@@ -433,7 +433,7 @@ class User < ActiveRecord::Base
   #
   # This logic is duplicated from `Ability#project_abilities` into a SQL form.
   def projects_where_can_admin_issues
-    authorized_projects(Gitlab::Access::REPORTER).non_archived.where.not(issues_enabled: false)
+    authorized_projects(Gitlab::Access::REPORTER).non_archived.with_issues_enabled
   end
 
   def is_admin?
@@ -460,16 +460,12 @@ class User < ActiveRecord::Base
     can?(:create_group, nil)
   end
 
-  def abilities
-    Ability.abilities
-  end
-
   def can_select_namespace?
     several_namespaces? || admin
   end
 
   def can?(action, subject)
-    abilities.allowed?(self, action, subject)
+    Ability.allowed?(self, action, subject)
   end
 
   def first_name