Merge remote-tracking branch 'upstream/master' into ce-to-ee-2018-03-08

# Conflicts:
#	Gemfile.lock
#	app/models/members/project_member.rb
#	app/views/import/github/new.html.haml
#	db/schema.rb
#	doc/api/merge_requests.md
#	locale/gitlab.pot
#	spec/policies/project_policy_spec.rb

[ci skip]

GITLAB_PAGES_VERSION

-0.6.1
+0.7.0

Gemfile

@@ -428,9 +428,7 @@ end
 
 # Gitaly GRPC client
 gem 'gitaly-proto', '~> 0.88.0', require: 'gitaly'
-# Explicitly lock grpc as we know 1.9 is bad
-# 1.10 is still being tested. See gitlab-org/gitaly#1059
-gem 'grpc', '~> 1.8.3'
+gem 'grpc', '~> 1.10.0'
 
 # Locked until https://github.com/google/protobuf/issues/4210 is closed
 gem 'google-protobuf', '= 3.5.1'

Gemfile.lock

@@ -371,9 +371,9 @@ GEM
     google-protobuf (3.5.1)
     googleapis-common-protos-types (1.0.1)
       google-protobuf (~> 3.0)
-    googleauth (0.5.3)
+    googleauth (0.6.2)
       faraday (~> 0.12)
-      jwt (~> 1.4)
+      jwt (>= 1.4, < 3.0)
       logging (~> 2.0)
       memoist (~> 0.12)
       multi_json (~> 1.11)
@@ -397,7 +397,7 @@ GEM
       rake
     grape_logging (1.7.0)
       grape
-    grpc (1.8.3)
+    grpc (1.10.0)
       google-protobuf (~> 3.1)
       googleapis-common-protos-types (~> 1.0.0)
       googleauth (>= 0.5.1, < 0.7)
@@ -678,7 +678,7 @@ GEM
       pry (~> 0.10)
     pry-rails (0.3.5)
       pry (>= 0.9.10)
-    public_suffix (3.0.0)
+    public_suffix (3.0.2)
     pyu-ruby-sasl (0.0.3.3)
     rack (1.6.8)
     rack-accept (0.4.5)
@@ -892,10 +892,10 @@ GEM
       sidekiq (>= 4.2.1)
     sidekiq-limit_fetch (3.4.0)
       sidekiq (>= 4)
-    signet (0.7.3)
+    signet (0.8.1)
       addressable (~> 2.3)
       faraday (~> 0.9)
-      jwt (~> 1.5)
+      jwt (>= 1.5, < 3.0)
       multi_json (~> 1.10)
     simple_po_parser (1.1.2)
     simplecov (0.14.1)
@@ -1114,8 +1114,12 @@ DEPENDENCIES
   grape-entity (~> 0.6.0)
   grape-route-helpers (~> 2.1.0)
   grape_logging (~> 1.7)
+<<<<<<< HEAD
   grpc (~> 1.8.3)
   gssapi
+=======
+  grpc (~> 1.10.0)
+>>>>>>> upstream/master
   haml_lint (~> 0.26.0)
   hamlit (~> 2.6.1)
   hashie-forbidden_attributes

PROCESS.md

@@ -71,7 +71,7 @@ star, smile, etc.). Some good tips about code reviews can be found in our
 
 ## Feature freeze on the 7th for the release on the 22nd
 
-After 7th at 23:59 (Pacific Standard Time Zone) of each month, RC1 of the upcoming release (to be shipped on the 22nd) is created and deployed to GitLab.com and the stable branch for this release is frozen, which means master is no longer merged into it.
+After 7th at 23:59 (Pacific Time Zone) of each month, RC1 of the upcoming release (to be shipped on the 22nd) is created and deployed to GitLab.com and the stable branch for this release is frozen, which means master is no longer merged into it.
 Merge requests may still be merged into master during this period,
 but they will go into the _next_ release, unless they are manually cherry-picked into the stable branch.
 

app/assets/javascripts/prometheus_metrics/prometheus_metrics.js

+import _ from 'underscore';
+import { s__, n__, sprintf } from '~/locale';
 import axios from '../lib/utils/axios_utils';
 import PANEL_STATE from './constants';
 import { backOff } from '../lib/utils/common_utils';
@@ -20,6 +22,7 @@ export default class PrometheusMetrics {
     this.$missingEnvVarMetricsList = this.$missingEnvVarPanel.find('.js-missing-var-metrics-list');
 
     this.activeMetricsEndpoint = this.$monitoredMetricsPanel.data('activeMetrics');
+    this.helpMetricsPath = this.$monitoredMetricsPanel.data('metrics-help-path');
 
     this.$panelToggle.on('click', e => this.handlePanelToggle(e));
   }
@@ -59,25 +62,41 @@ export default class PrometheusMetrics {
   populateActiveMetrics(metrics) {
     let totalMonitoredMetrics = 0;
     let totalMissingEnvVarMetrics = 0;
+    let totalExporters = 0;
 
     metrics.forEach((metric) => {
-      this.$monitoredMetricsList.append(`<li>${metric.group}<span class="badge">${metric.active_metrics}</span></li>`);
+      if (metric.active_metrics > 0) {
+        totalExporters += 1;
+        this.$monitoredMetricsList.append(`<li>${_.escape(metric.group)}<span class="badge">${_.escape(metric.active_metrics)}</span></li>`);
         totalMonitoredMetrics += metric.active_metrics;
         if (metric.metrics_missing_requirements > 0) {
-        this.$missingEnvVarMetricsList.append(`<li>${metric.group}</li>`);
+          this.$missingEnvVarMetricsList.append(`<li>${_.escape(metric.group)}</li>`);
           totalMissingEnvVarMetrics += 1;
         }
+      }
     });
 
-    this.$monitoredMetricsCount.text(totalMonitoredMetrics);
+    if (totalMonitoredMetrics === 0) {
+      const emptyCommonMetricsText = sprintf(s__('PrometheusService|<p class="text-tertiary">No <a href="%{docsUrl}">common metrics</a> were found</p>'), {
+        docsUrl: this.helpMetricsPath,
+      }, false);
+      this.$monitoredMetricsEmpty.empty();
+      this.$monitoredMetricsEmpty.append(emptyCommonMetricsText);
+      this.showMonitoringMetricsPanelState(PANEL_STATE.EMPTY);
+    } else {
+      const metricsCountText = sprintf(s__('PrometheusService|%{exporters} with %{metrics} were found'), {
+        exporters: n__('%d exporter', '%d exporters', totalExporters),
+        metrics: n__('%d metric', '%d metrics', totalMonitoredMetrics),
+      });
+      this.$monitoredMetricsCount.text(metricsCountText);
       this.showMonitoringMetricsPanelState(PANEL_STATE.LIST);
 
       if (totalMissingEnvVarMetrics > 0) {
         this.$missingEnvVarPanel.removeClass('hidden');
-      this.$missingEnvVarPanel.find('.flash-container').off('click');
         this.$missingEnvVarMetricCount.text(totalMissingEnvVarMetrics);
       }
     }
+  }
 
   loadActiveMetrics() {
     this.showMonitoringMetricsPanelState(PANEL_STATE.LOADING);

app/assets/javascripts/terminal/terminal.js

@@ -6,8 +6,14 @@
     constructor(options) {
       this.options = options || {};
 
-      this.options.cursorBlink = options.cursorBlink || true;
-      this.options.screenKeys = options.screenKeys || true;
+      if (!Object.prototype.hasOwnProperty.call(this.options, 'cursorBlink')) {
+        this.options.cursorBlink = true;
+      }
+
+      if (!Object.prototype.hasOwnProperty.call(this.options, 'screenKeys')) {
+        this.options.screenKeys = true;
+      }
+
       this.container = document.querySelector(options.selector);
 
       this.setSocketUrl();

app/assets/javascripts/vue_merge_request_widget/components/mr_widget_maintainer_edit.vue

+<script>
+  export default {
+    name: 'MRWidgetMaintainerEdit',
+    props: {
+      maintainerEditAllowed: {
+        type: Boolean,
+        default: false,
+        required: false,
+      },
+    },
+  };
+</script>
+
+<template>
+  <section class="mr-info-list mr-links">
+    <p v-if="maintainerEditAllowed">
+      {{ s__("mrWidget|Allows edits from maintainers") }}
+    </p>
+  </section>
+</template>

app/assets/javascripts/vue_merge_request_widget/dependencies.js

@@ -15,6 +15,7 @@ export { default as WidgetHeader } from './components/mr_widget_header.vue';
 export { default as WidgetMergeHelp } from './components/mr_widget_merge_help.vue';
 export { default as WidgetPipeline } from './components/mr_widget_pipeline.vue';
 export { default as WidgetDeployment } from './components/mr_widget_deployment';
+export { default as WidgetMaintainerEdit } from './components/mr_widget_maintainer_edit.vue';
 export { default as WidgetRelatedLinks } from './components/mr_widget_related_links.vue';
 export { default as MergedState } from './components/states/mr_widget_merged.vue';
 export { default as FailedToMerge } from './components/states/mr_widget_failed_to_merge.vue';

app/assets/javascripts/vue_merge_request_widget/mr_widget_options.js

@@ -6,6 +6,7 @@ import {
   WidgetMergeHelp,
   WidgetPipeline,
   WidgetDeployment,
+  WidgetMaintainerEdit,
   WidgetRelatedLinks,
   MergedState,
   ClosedState,
@@ -212,6 +213,7 @@ export default {
     'mr-widget-merge-help': WidgetMergeHelp,
     'mr-widget-pipeline': WidgetPipeline,
     'mr-widget-deployment': WidgetDeployment,
+    'mr-widget-maintainer-edit': WidgetMaintainerEdit,
     'mr-widget-related-links': WidgetRelatedLinks,
     'mr-widget-merged': MergedState,
     'mr-widget-closed': ClosedState,
@@ -252,11 +254,12 @@ export default {
           :is="componentName"
           :mr="mr"
           :service="service" />
+        <mr-widget-maintainer-edit
+          :maintainerEditAllowed="mr.maintainerEditAllowed" />
         <mr-widget-related-links
           v-if="shouldRenderRelatedLinks"
           :state="mr.state"
-          :related-links="mr.relatedLinks"
-          />
+          :related-links="mr.relatedLinks" />
       </div>
       <div
         class="mr-widget-footer"

app/assets/javascripts/vue_merge_request_widget/stores/mr_widget_store.js

@@ -79,6 +79,7 @@ export default class MergeRequestStore {
     this.canBeMerged = data.can_be_merged || false;
     this.isMergeAllowed = data.mergeable || false;
     this.mergeOngoing = data.merge_ongoing;
+    this.maintainerEditAllowed = data.allow_maintainer_to_push;
 
     // Cherry-pick and Revert actions related
     this.canCherryPickInCurrentMR = currentUser.can_cherry_pick_on_current_merge_request || false;

app/assets/stylesheets/framework/common.scss

@@ -14,6 +14,10 @@
   color: $gl-text-color-secondary;
 }
 
+.text-tertiary {
+  color: $gl-text-color-tertiary;
+}
+
 .text-primary,
 .text-primary:hover {
   color: $brand-primary;

app/assets/stylesheets/framework/dropdowns.scss

@@ -272,7 +272,7 @@
 
   .divider {
     height: 1px;
-    margin: 6px 0;
+    margin: #{$grid-size / 2} 0;
     padding: 0;
     background-color: $dropdown-divider-color;
 

app/assets/stylesheets/framework/flash.scss

@@ -12,6 +12,12 @@
     margin: 0;
   }
 
+  .flash-warning {
+    @extend .alert;
+    @extend .alert-warning;
+    margin: 0;
+  }
+
   .flash-alert {
     @extend .alert;
     @extend .alert-danger;

app/assets/stylesheets/pages/settings.scss

@@ -230,7 +230,8 @@
     }
 
     .badge {
-      font-size: inherit;
+      font-size: 12px;
+      line-height: 12px;
     }
 
     .panel-heading .badge-count {

app/controllers/concerns/creates_commit.rb

@@ -4,7 +4,7 @@ module CreatesCommit
 
   # rubocop:disable Gitlab/ModuleWithInstanceVariables
   def create_commit(service, success_path:, failure_path:, failure_view: nil, success_notice: nil)
-    if can?(current_user, :push_code, @project)
+    if user_access(@project).can_push_to_branch?(branch_name_or_ref)
       @project_to_commit_into = @project
       @branch_name ||= @ref
     else
@@ -50,7 +50,7 @@ module CreatesCommit
   # rubocop:enable Gitlab/ModuleWithInstanceVariables
 
   def authorize_edit_tree!
-    return if can_collaborate_with_project?
+    return if can_collaborate_with_project?(project, ref: branch_name_or_ref)
 
     access_denied!
   end
@@ -123,4 +123,8 @@ module CreatesCommit
     params[:create_merge_request].present? &&
       (different_project? || @start_branch != @branch_name) # rubocop:disable Gitlab/ModuleWithInstanceVariables
   end
+
+  def branch_name_or_ref
+    @branch_name || @ref # rubocop:disable Gitlab/ModuleWithInstanceVariables
+  end
 end

app/controllers/projects/application_controller.rb

@@ -7,7 +7,7 @@ class Projects::ApplicationController < ApplicationController
   before_action :repository
   layout 'project'
 
-  helper_method :repository, :can_collaborate_with_project?
+  helper_method :repository, :can_collaborate_with_project?, :user_access
 
   private
 
@@ -32,11 +32,12 @@ class Projects::ApplicationController < ApplicationController
     @repository ||= project.repository
   end
 
-  def can_collaborate_with_project?(project = nil)
+  def can_collaborate_with_project?(project = nil, ref: nil)
     project ||= @project
 
     can?(current_user, :push_code, project) ||
-      (current_user && current_user.already_forked?(project))
+      (current_user && current_user.already_forked?(project)) ||
+      user_access(project).can_push_to_branch?(ref)
   end
 
   def authorize_action!(action)
@@ -91,4 +92,9 @@ class Projects::ApplicationController < ApplicationController
   def check_issues_available!
     return render_404 unless @project.feature_available?(:issues, current_user)
   end
+
+  def user_access(project)
+    @user_access ||= {}
+    @user_access[project] ||= Gitlab::UserAccess.new(current_user, project: project)
+  end
 end

app/controllers/projects/blob_controller.rb

@@ -9,8 +9,12 @@ class Projects::BlobController < Projects::ApplicationController
 
   before_action :require_non_empty_project, except: [:new, :create]
   before_action :authorize_download_code!
-  before_action :authorize_edit_tree!, only: [:new, :create, :update, :destroy]
+
+  # We need to assign the blob vars before `authorize_edit_tree!` so we can
+  # validate access to a specific ref.
   before_action :assign_blob_vars
+  before_action :authorize_edit_tree!, only: [:new, :create, :update, :destroy]
+
   before_action :commit, except: [:new, :create]
   before_action :blob, except: [:new, :create]
   before_action :require_branch_head, only: [:edit, :update]
@@ -46,7 +50,7 @@ class Projects::BlobController < Projects::ApplicationController
   end
 
   def edit
-    if can_collaborate_with_project?
+    if can_collaborate_with_project?(project, ref: @ref)
       blob.load_all_data!
     else
       redirect_to action: 'show'

app/controllers/projects/merge_requests/application_controller.rb

@@ -17,6 +17,7 @@ class Projects::MergeRequests::ApplicationController < Projects::ApplicationCont
 
   def merge_request_params_attributes
     [
+      :allow_maintainer_to_push,
       :assignee_id,
       :description,
       :force_remove_source_branch,

app/helpers/merge_requests_helper.rb

@@ -165,6 +165,19 @@ module MergeRequestsHelper
     link_to(url[merge_request.project, merge_request], data: data_attrs, &block)
   end
 
+  def allow_maintainer_push_unavailable_reason(merge_request)
+    return if merge_request.can_allow_maintainer_to_push?(current_user)
+
+    minimum_visibility = [merge_request.target_project.visibility_level,
+                          merge_request.source_project.visibility_level].min
+
+    if minimum_visibility < Gitlab::VisibilityLevel::INTERNAL
+      _('Not available for private projects')
+    elsif ProtectedBranch.protected?(merge_request.source_project, merge_request.source_branch)
+      _('Not available for protected branches')
+    end
+  end
+
   def merge_params_ee(merge_request)
     { squash: merge_request.squash }
   end

app/helpers/tree_helper.rb

@@ -49,15 +49,13 @@ module TreeHelper
 
     return false unless on_top_of_branch?(project, ref)
 
-    can_collaborate_with_project?(project)
+    can_collaborate_with_project?(project, ref: ref)
   end
 
   def tree_edit_branch(project = @project, ref = @ref)
     return unless can_edit_tree?(project, ref)
 
-    project = project.present(current_user: current_user)
-
-    if project.can_current_user_push_to_branch?(ref)
+    if user_access(project).can_push_to_branch?(ref)
       ref
     else
       project = tree_edit_project(project)
@@ -88,7 +86,16 @@ module TreeHelper
   end
 
   def commit_in_fork_help
-    "A new branch will be created in your fork and a new merge request will be started."
+    _("A new branch will be created in your fork and a new merge request will be started.")
+  end
+
+  def commit_in_single_accessible_branch
+    branch_name = html_escape(selected_branch)
+
+    message = _("Your changes can be committed to %{branch_name} because a merge "\
+                "request is open.") % { branch_name: "<strong>#{branch_name}</strong>" }
+
+    message.html_safe
   end
 
   def path_breadcrumbs(max_links = 6)
@@ -125,4 +132,8 @@ module TreeHelper
       return tree.name
     end
   end
+
+  def selected_branch
+    @branch_name || tree_edit_branch
+  end
 end

app/models/members/project_member.rb

@@ -13,8 +13,11 @@ class ProjectMember < Member
 
   scope :in_project, ->(project) { where(source_id: project.id) }
 
+<<<<<<< HEAD
   before_destroy :delete_member_branch_protection
 
+=======
+>>>>>>> upstream/master
   class << self
     # Add users to projects with passed access option
     #
@@ -93,6 +96,7 @@ class ProjectMember < Member
 
   private
 
+<<<<<<< HEAD
   def delete_member_branch_protection
     if user.present? && project.present?
       project.protected_branches.merge_access_by_user(user).destroy_all
@@ -100,6 +104,8 @@ class ProjectMember < Member
     end
   end
 
+=======
+>>>>>>> upstream/master
   def send_invite
     notification_service.invite_project_member(self, @raw_invite_token) unless @skip_notification
 

app/models/merge_request.rb

@@ -892,7 +892,7 @@ class MergeRequest < ActiveRecord::Base
 
   def can_be_merged_by?(user)
     access = ::Gitlab::UserAccess.new(user, project: project)
-    access.can_push_to_branch?(target_branch) || access.can_merge_to_branch?(target_branch)
+    access.can_update_branch?(target_branch)
   end
 
   def can_be_merged_via_command_line_by?(user)
@@ -1118,4 +1118,22 @@ class MergeRequest < ActiveRecord::Base
 
     project.merge_requests.merged.where(author_id: author_id).empty?
   end
+
+  def allow_maintainer_to_push
+    maintainer_push_possible? && super
+  end
+
+  alias_method :allow_maintainer_to_push?, :allow_maintainer_to_push
+
+  def maintainer_push_possible?
+    source_project.present? && for_fork? &&
+      target_project.visibility_level > Gitlab::VisibilityLevel::PRIVATE &&
+      source_project.visibility_level > Gitlab::VisibilityLevel::PRIVATE &&
+      !ProtectedBranch.protected?(source_project, source_branch)
+  end
+
+  def can_allow_maintainer_to_push?(user)
+    maintainer_push_possible? &&
+      Ability.allowed?(user, :push_code, source_project)
+  end
 end

app/models/project.rb

@@ -155,6 +155,7 @@ class Project < ActiveRecord::Base
 
   # Merge Requests for target project should be removed with it
   has_many :merge_requests, foreign_key: 'target_project_id'
+  has_many :source_of_merge_requests, foreign_key: 'source_project_id', class_name: 'MergeRequest'
   has_many :issues
   has_many :labels, class_name: 'ProjectLabel'
   has_many :services
@@ -1805,6 +1806,33 @@ class Project < ActiveRecord::Base
     Badge.where("id IN (#{union.to_sql})") # rubocop:disable GitlabSecurity/SqlInjection
   end
 
+  def merge_requests_allowing_push_to_user(user)
+    return MergeRequest.none unless user
+
+    developer_access_exists = user.project_authorizations
+                                .where('access_level >= ? ', Gitlab::Access::DEVELOPER)
+                                .where('project_authorizations.project_id = merge_requests.target_project_id')
+                                .limit(1)
+                                .select(1)
+    source_of_merge_requests.opened
+      .where(allow_maintainer_to_push: true)
+      .where('EXISTS (?)', developer_access_exists)
+  end
+
+  def branch_allows_maintainer_push?(user, branch_name)
+    return false unless user
+
+    cache_key = "user:#{user.id}:#{branch_name}:branch_allows_push"
+
+    memoized_results = strong_memoize(:branch_allows_maintainer_push) do
+      Hash.new do |result, cache_key|
+        result[cache_key] = fetch_branch_allows_maintainer_push?(user, branch_name)
+      end
+    end
+
+    memoized_results[cache_key]
+  end
+
   private
 
   def storage
@@ -1927,4 +1955,22 @@ class Project < ActiveRecord::Base
 
     raise ex
   end
+
+  def fetch_branch_allows_maintainer_push?(user, branch_name)
+    check_access = -> do
+      merge_request = source_of_merge_requests.opened
+                        .where(allow_maintainer_to_push: true)
+                        .find_by(source_branch: branch_name)
+
+      merge_request&.can_be_merged_by?(user)
+    end
+
+    if RequestStore.active?
+      RequestStore.fetch("project-#{id}:branch-#{branch_name}:user-#{user.id}:branch_allows_maintainer_push") do
+        check_access.call
+      end
+    else
+      check_access.call
+    end
+  end
 end

app/models/repository.rb

@@ -658,14 +658,15 @@ class Repository
   end
 
   def last_commit_for_path(sha, path)
-    commit_by(oid: last_commit_id_for_path(sha, path))
+    commit = raw_repository.last_commit_for_path(sha, path)
+    ::Commit.new(commit, @project) if commit
   end
 
   def last_commit_id_for_path(sha, path)
     key = path.blank? ? "last_commit_id_for_path:#{sha}" : "last_commit_id_for_path:#{sha}:#{Digest::SHA1.hexdigest(path)}"
 
     cache.fetch(key) do
-      raw_repository.last_commit_id_for_path(sha, path)
+      last_commit_for_path(sha, path)&.id
     end
   end
 

app/policies/project_policy.rb

@@ -63,6 +63,11 @@ class ProjectPolicy < BasePolicy
   desc "Project has request access enabled"
   condition(:request_access_enabled, scope: :subject) { project.request_access_enabled }
 
+  desc "Has merge requests allowing pushes to user"
+  condition(:has_merge_requests_allowing_pushes, scope: :subject) do
+    project.merge_requests_allowing_push_to_user(user).any?
+  end
+
   features = %w[
     merge_requests
     issues
@@ -293,6 +298,15 @@ class ProjectPolicy < BasePolicy
     prevent :read_issue
   end
 
+  # These rules are included to allow maintainers of projects to push to certain
+  # to run pipelines for the branches they have access to.
+  rule { can?(:public_access) & has_merge_requests_allowing_pushes }.policy do
+    enable :create_build
+    enable :update_build
+    enable :create_pipeline
+    enable :update_pipeline
+  end
+
   private
 
   def team_member?

app/presenters/merge_request_presenter.rb

@@ -78,7 +78,7 @@ class MergeRequestPresenter < Gitlab::View::Presenter::Delegated
   end
 
   def rebase_path
-    if !rebase_in_progress? && should_be_rebased? && user_can_push_to_source_branch?
+    if !rebase_in_progress? && should_be_rebased? && can_push_to_source_branch?
       rebase_project_merge_request_path(project, merge_request)
     end
   end
@@ -166,7 +166,11 @@ class MergeRequestPresenter < Gitlab::View::Presenter::Delegated
   end
 
   def can_push_to_source_branch?
-    source_branch_exists? && user_can_push_to_source_branch?
+    return false unless source_branch_exists?
+
+    !!::Gitlab::UserAccess
+      .new(current_user, project: source_project)
+      .can_push_to_branch?(source_branch)
   end
 
   private
@@ -197,17 +201,10 @@ class MergeRequestPresenter < Gitlab::View::Presenter::Delegated
     end.sort.to_sentence
   end
 
-  def user_can_push_to_source_branch?
-    return false unless source_branch_exists?
-
-    ::Gitlab::UserAccess
-      .new(current_user, project: source_project)
-      .can_push_to_branch?(source_branch)
-  end
-
   def user_can_collaborate_with_project?
     can?(current_user, :push_code, project) ||
-      (current_user && current_user.already_forked?(project))
+      (current_user && current_user.already_forked?(project)) ||
+      can_push_to_source_branch?
   end
 
   def user_can_fork_project?

app/serializers/merge_request_widget_entity.rb

@@ -13,6 +13,7 @@ class MergeRequestWidgetEntity < IssuableEntity
   expose :source_project_id
   expose :target_branch
   expose :target_project_id
+  expose :allow_maintainer_to_push
 
   expose :should_be_rebased?, as: :should_be_rebased
   expose :ff_only_enabled do |merge_request|
@@ -48,6 +49,7 @@ class MergeRequestWidgetEntity < IssuableEntity
   expose :can_push_to_source_branch do |merge_request|
     presenter(merge_request).can_push_to_source_branch?
   end
+
   expose :rebase_path do |merge_request|
     presenter(merge_request).rebase_path
   end
@@ -155,8 +157,8 @@ class MergeRequestWidgetEntity < IssuableEntity
   end
 
   expose :new_blob_path do |merge_request|
-    if can?(current_user, :push_code, merge_request.project)
-      project_new_blob_path(merge_request.project, merge_request.source_branch)
+    if presenter(merge_request).can_push_to_source_branch?
+      project_new_blob_path(merge_request.source_project, merge_request.source_branch)
     end
   end
 

app/services/ci/create_pipeline_service.rb

@@ -89,7 +89,7 @@ module Ci
     end
 
     def related_merge_requests
-      MergeRequest.opened.where(source_project: pipeline.project, source_branch: pipeline.ref)
+      pipeline.project.source_of_merge_requests.opened.where(source_branch: pipeline.ref)
     end
   end
 end

app/services/merge_requests/base_service.rb

@@ -37,6 +37,14 @@ module MergeRequests
       end
     end
 
+    def filter_params(merge_request)
+      super
+
+      unless merge_request.can_allow_maintainer_to_push?(current_user)
+        params.delete(:allow_maintainer_to_push)
+      end
+    end
+
     def merge_request_metrics_service(merge_request)
       MergeRequestMetricsService.new(merge_request.metrics)
     end

app/services/merge_requests/build_service.rb

@@ -7,6 +7,7 @@ module MergeRequests
       @params_issue_iid = params.delete(:issue_iid)
 
       self.merge_request = MergeRequest.new(params)
+      merge_request.author = current_user
       merge_request.compare_commits = []
       merge_request.source_project  = find_source_project
       merge_request.target_project  = find_target_project

app/views/import/github/new.html.haml

@@ -23,7 +23,10 @@
     = submit_tag _('List your GitHub repositories'), class: 'btn btn-success'
 
   -# EE-specific start
+<<<<<<< HEAD
   = hidden_field_tag :ci_cd_only, params[:ci_cd_only]
+=======
+>>>>>>> upstream/master
   -# EE-specific end
 
 - unless github_import_configured?

app/views/projects/_commit_button.html.haml

@@ -3,6 +3,4 @@
   = link_to 'Cancel', cancel_path,
             class: 'btn btn-cancel', data: {confirm: leave_edit_message}
 
-  - unless can?(current_user, :push_code, @project)
-    .inline.prepend-left-10
-      = commit_in_fork_help
+  = render 'shared/projects/edit_information'

app/views/projects/blob/_new_dir.html.haml

@@ -17,6 +17,4 @@
             = submit_tag _("Create directory"), class: 'btn btn-create'
             = link_to "Cancel", '#', class: "btn btn-cancel", "data-dismiss" => "modal"
 
-            - unless can?(current_user, :push_code, @project)
-              .inline.prepend-left-10
-                = commit_in_fork_help
+            = render 'shared/projects/edit_information'

app/views/projects/blob/_upload.html.haml

@@ -24,6 +24,4 @@
               = button_title
             = link_to _("Cancel"), '#', class: "btn btn-cancel", "data-dismiss" => "modal"
 
-            - unless can?(current_user, :push_code, @project)
-              .inline.prepend-left-10
-                = commit_in_fork_help
+            = render 'shared/projects/edit_information'

app/views/projects/clusters/_integration_form.html.haml

@@ -20,6 +20,12 @@
           = sprite_icon('status_success_borderless', size: 16, css_class: 'toggle-icon-svg toggle-status-checked')
           = sprite_icon('status_failed_borderless', size: 16, css_class: 'toggle-icon-svg toggle-status-unchecked')
 
+  .form-group
+    %h5= s_('ClusterIntegration|Security')
+    %p
+      = s_("ClusterIntegration|The default cluster configuration grants access to a wide set of functionalities needed to successfully build and deploy a containerised application.")
+      = link_to s_("ClusterIntegration|Learn more about security configuration"),  help_page_path('user/project/clusters/index.md', anchor: 'security-implications')
+
   .form-group
     %h5= s_('ClusterIntegration|Environment scope')
     %p

app/views/projects/commit/_change.html.haml

@@ -35,6 +35,4 @@
             = submit_tag label, class: 'btn btn-create'
             = link_to _("Cancel"), '#', class: "btn btn-cancel", "data-dismiss" => "modal"
 
-            - unless can?(current_user, :push_code, @project)
-              .inline.prepend-left-10
-                = commit_in_fork_help
+            = render 'shared/projects/edit_information'

app/views/projects/services/prometheus/_show.html.haml

@@ -7,21 +7,19 @@
       = link_to s_('PrometheusService|More information'), help_page_path('user/project/integrations/prometheus')
 
   .col-lg-9
-    .panel.panel-default.js-panel-monitored-metrics{ data: { active_metrics: active_common_project_prometheus_metrics_path(@project, :json) } }
+    .panel.panel-default.js-panel-monitored-metrics{ data: { active_metrics: active_common_project_prometheus_metrics_path(@project, :json), metrics_help_path: help_page_path('user/project/integrations/prometheus_library/metrics') } }
       .panel-heading
         %h3.panel-title
-          = s_('PrometheusService|Monitored')
+          = s_('PrometheusService|Common metrics')
           %span.badge.js-monitored-count 0
       .panel-body
-        .loading-metrics.text-center.js-loading-metrics
-          = icon('spinner spin 3x', class: 'metrics-load-spinner')
-          %p
+        .loading-metrics.js-loading-metrics
+          %p.prepend-top-10.prepend-left-10
+            = icon('spinner spin', class: 'metrics-load-spinner')
             = s_('PrometheusService|Finding and configuring metrics...')
-        .empty-metrics.text-center.hidden.js-empty-metrics
-          = custom_icon('icon_empty_metrics')
-          %p
-            = s_('PrometheusService|No metrics are being monitored. To start monitoring, deploy to an environment.')
-          = link_to s_('PrometheusService|View environments'), project_environments_path(@project), class: 'btn btn-success'
+        .empty-metrics.hidden.js-empty-metrics
+          %p.text-tertiary.prepend-top-10.prepend-left-10
+            = s_('PrometheusService|Waiting for your first deployment to an environment to find common metrics')
         %ul.list-unstyled.metrics-list.hidden.js-metrics-list
 
     .panel.panel-default.hidden.js-panel-missing-env-vars

app/views/shared/_new_commit_form.html.haml

+- project = @project.present(current_user: current_user)
+- branch_name = selected_branch
+
 = render 'shared/commit_message_container', placeholder: placeholder
 
 - if @project.empty_repo?
@@ -7,12 +10,14 @@
     .form-group.branch
       = label_tag 'branch_name', _('Target Branch'), class: 'control-label'
       .col-sm-10
-        = text_field_tag 'branch_name', @branch_name || tree_edit_branch, required: true, class: "form-control js-branch-name ref-name"
+        = text_field_tag 'branch_name', branch_name, required: true, class: "form-control js-branch-name ref-name"
 
         .js-create-merge-request-container
           = render 'shared/new_merge_request_checkbox'
+  - elsif project.can_current_user_push_to_branch?(branch_name)
+    = hidden_field_tag 'branch_name', branch_name
   - else
-    = hidden_field_tag 'branch_name', @branch_name || tree_edit_branch
+    = hidden_field_tag 'branch_name', branch_name
     = hidden_field_tag 'create_merge_request', 1
 
   = hidden_field_tag 'original_branch', @ref, class: 'js-original-branch'

app/views/shared/issuable/_form.html.haml

@@ -35,6 +35,8 @@
 
 = render 'shared/issuable/form/merge_params', issuable: issuable
 
+= render 'shared/issuable/form/contribution', issuable: issuable, form: form
+
 - if @merge_request_to_resolve_discussions_of
   .form-group
     .col-sm-10.col-sm-offset-2

app/views/shared/issuable/form/_contribution.html.haml

+- issuable = local_assigns.fetch(:issuable)
+- form = local_assigns.fetch(:form)
+
+- return unless issuable.is_a?(MergeRequest)
+- return unless issuable.for_fork?
+- return unless can?(current_user, :push_code, issuable.source_project)
+
+%hr
+
+.form-group
+  .control-label
+    = _('Contribution')
+  .col-sm-10
+    .checkbox
+      = form.label :allow_maintainer_to_push do
+        = form.check_box :allow_maintainer_to_push, disabled: !issuable.can_allow_maintainer_to_push?(current_user)
+        = _('Allow edits from maintainers')
+        = link_to 'About this feature', help_page_path('user/project/merge_requests/maintainer_access')
+        .help-block
+          = allow_maintainer_push_unavailable_reason(issuable)

app/views/shared/projects/_edit_information.html.haml

+- unless can?(current_user, :push_code, @project)
+  .inline.prepend-left-10
+    - if @project.branch_allows_maintainer_push?(current_user, selected_branch)
+      = commit_in_single_accessible_branch
+    - else
+      = commit_in_fork_help

changelogs/unreleased/39444-make-margin-around-dropdown-dividers-4px.yml

+---
+title: Set margins around dropdown dividers to 4px
+merge_request: 17517
+author:
+type: fixed

changelogs/unreleased/43780-add-a-paragraph-about-clusters-security-implications.yml

+---
+title: Add a paragraph about security implications on Cluster's page
+merge_request: 17486
+author:
+type: added

changelogs/unreleased/bvl-allow-maintainer-to-push.yml

+---
+title: Allow maintainers to push to forks of their projects when a merge request is open
+merge_request: 17395
+author:
+type: added

db/migrate/20180221151752_add_allow_maintainer_to_push_to_merge_requests.rb

+# See http://doc.gitlab.com/ce/development/migration_style_guide.html
+# for more information on how to write migrations for GitLab.
+
+class AddAllowMaintainerToPushToMergeRequests < ActiveRecord::Migration
+  include Gitlab::Database::MigrationHelpers
+
+  DOWNTIME = false
+
+  disable_ddl_transaction!
+
+  def up
+    add_column :merge_requests, :allow_maintainer_to_push, :boolean
+  end
+
+  def down
+    remove_column :merge_requests, :allow_maintainer_to_push
+  end
+end

db/schema.rb

@@ -1531,6 +1531,11 @@ ActiveRecord::Schema.define(version: 20180307164427) do
     t.string "merge_jid"
     t.boolean "discussion_locked"
     t.integer "latest_merge_request_diff_id"
+<<<<<<< HEAD
+=======
+    t.string "rebase_commit_sha"
+    t.boolean "allow_maintainer_to_push"
+>>>>>>> upstream/master
   end
 
   add_index "merge_requests", ["assignee_id"], name: "index_merge_requests_on_assignee_id", using: :btree

doc/api/merge_requests.md

@@ -535,6 +535,7 @@ Creates a new merge request.
 POST /projects/:id/merge_requests
 ```
 
+<<<<<<< HEAD
 | Attribute              | Type    | Required | Description                                                                     |
 | ---------              | ----    | -------- | -----------                                                                     |
 | `id`                   | integer/string  | yes      | The ID or [URL-encoded path of the project](README.md#namespaced-path-encoding) owned by the authenticated user |
@@ -558,6 +559,21 @@ order for it to take effect:
    value of zero disables approvals for that project.)
 2. The provided value of `approvals_before_merge` must be greater than the
    target project's `approvals_before_merge`.
+=======
+| Attribute                  | Type    | Required | Description                                                                     |
+| ---------                  | ----    | -------- | -----------                                                                     |
+| `id`                       | integer/string  | yes      | The ID or [URL-encoded path of the project](README.md#namespaced-path-encoding) owned by the authenticated user |
+| `source_branch`            | string  | yes      | The source branch                                                               |
+| `target_branch`            | string  | yes      | The target branch                                                               |
+| `title`                    | string  | yes      | Title of MR                                                                     |
+| `assignee_id`              | integer | no       | Assignee user ID                                                                |
+| `description`              | string  | no       | Description of MR                                                               |
+| `target_project_id`        | integer | no       | The target project (numeric id)                                                 |
+| `labels`                   | string  | no       | Labels for MR as a comma-separated list                                         |
+| `milestone_id`             | integer | no       | The ID of a milestone                                                           |
+| `remove_source_branch`     | boolean | no       | Flag indicating if a merge request should remove the source branch when merging |
+| `allow_maintainer_to_push` | boolean | no       | Whether or not a maintainer of the target project can push to the source branch  |
+>>>>>>> upstream/master
 
 ```json
 {
@@ -565,7 +581,7 @@ order for it to take effect:
   "iid": 1,
   "target_branch": "master",
   "source_branch": "test1",
-  "project_id": 3,
+  "project_id": 4,
   "title": "test1",
   "state": "opened",
   "upvotes": 0,
@@ -586,7 +602,7 @@ order for it to take effect:
     "state": "active",
     "created_at": "2012-04-29T08:46:00Z"
   },
-  "source_project_id": 4,
+  "source_project_id": 3,
   "target_project_id": 4,
   "labels": [ ],
   "description": "fixed login page css paddings",
@@ -614,6 +630,7 @@ order for it to take effect:
   "squash": false,
   "web_url": "http://example.com/example/example/merge_requests/1",
   "discussion_locked": false,
+  "allow_maintainer_to_push": false,
   "time_stats": {
     "time_estimate": 0,
     "total_time_spent": 0,
@@ -632,6 +649,7 @@ Updates an existing merge request. You can change the target branch, title, or e
 PUT /projects/:id/merge_requests/:merge_request_iid
 ```
 
+<<<<<<< HEAD
 | Attribute              | Type    | Required | Description                                                                     |
 | ---------              | ----    | -------- | -----------                                                                     |
 | `id`                   | integer/string | yes  | The ID or [URL-encoded path of the project](README.md#namespaced-path-encoding) owned by the authenticated user |
@@ -646,6 +664,22 @@ PUT /projects/:id/merge_requests/:merge_request_iid
 | `remove_source_branch` | boolean | no       | Flag indicating if a merge request should remove the source branch when merging |
 | `squash` | boolean| no | Squash commits into a single commit when merging |
 | `discussion_locked`    | boolean | no       | Flag indicating if the merge request's discussion is locked. If the discussion is locked only project members can add, edit or resolve comments. |
+=======
+| Attribute                  | Type    | Required | Description                                                                     |
+| ---------                  | ----    | -------- | -----------                                                                     |
+| `id`                       | integer/string | yes  | The ID or [URL-encoded path of the project](README.md#namespaced-path-encoding) owned by the authenticated user |
+| `merge_request_iid`        | integer | yes      | The ID of a merge request                                                       |
+| `target_branch`            | string  | no       | The target branch                                                               |
+| `title`                    | string  | no       | Title of MR                                                                     |
+| `assignee_id`              | integer | no       | The ID of the user to assign the merge request to. Set to `0` or provide an empty value to unassign all assignees.  |
+| `milestone_id`             | integer | no       | The ID of a milestone to assign the merge request to. Set to `0` or provide an empty value to unassign a milestone.|
+| `labels`                   | string  | no       | Comma-separated label names for a merge request. Set to an empty string to unassign all labels.                    |
+| `description`              | string  | no       | Description of MR                                                               |
+| `state_event`              | string  | no       | New state (close/reopen)                                                        |
+| `remove_source_branch`     | boolean | no       | Flag indicating if a merge request should remove the source branch when merging |
+| `discussion_locked`        | boolean | no       | Flag indicating if the merge request's discussion is locked. If the discussion is locked only project members can add, edit or resolve comments. |
+| `allow_maintainer_to_push` | boolean | no       | Whether or not a maintainer of the target project can push to the source branch |
+>>>>>>> upstream/master
 
 Must include at least one non-required attribute from above.
 
@@ -654,7 +688,7 @@ Must include at least one non-required attribute from above.
   "id": 1,
   "iid": 1,
   "target_branch": "master",
-  "project_id": 3,
+  "project_id": 4,
   "title": "test1",
   "state": "opened",
   "upvotes": 0,
@@ -675,7 +709,7 @@ Must include at least one non-required attribute from above.
     "state": "active",
     "created_at": "2012-04-29T08:46:00Z"
   },
-  "source_project_id": 4,
+  "source_project_id": 3,
   "target_project_id": 4,
   "labels": [ ],
   "description": "description1",
@@ -703,6 +737,7 @@ Must include at least one non-required attribute from above.
   "squash": false,
   "web_url": "http://example.com/example/example/merge_requests/1",
   "discussion_locked": false,
+  "allow_maintainer_to_push": false,
   "time_stats": {
     "time_estimate": 0,
     "total_time_spent": 0,

doc/development/new_fe_guide/dependencies.md

+# Dependencies
+
+> TODO: Add Dependencies
\ No newline at end of file

doc/development/new_fe_guide/development/accessibility.md

+# Accessibility
+
+> TODO: Add content

doc/development/new_fe_guide/development/components.md

+# Components
+
+> TODO: Add content

doc/development/new_fe_guide/development/design_patterns.md

+# Design patterns
+
+> TODO: Add content

doc/development/new_fe_guide/development/index.md

+# Development
+
+## [Design patterns](design_patterns.md)
+
+Examples of proven design patterns used in our codebase.
+
+## [Components](components.md)
+
+Documentation on existing components and how to best create a new component.
+
+## [Accessibility](accessibility.md)
+
+Learn how to implement an accessible frontend.
+
+## [Network requests](network_requests.md)
+
+Learn how to handle network requests in our codebase.
+
+## [Security](security.md)
+
+Learn how to ensure that our frontend is secure.
+
+## [Performance](performance.md)
+
+Learn how to keep our frontend performant.
+
+## [Testing](testing.md)
+
+Learn how to keep our frontend tested.

doc/development/new_fe_guide/development/network_requests.md

+# Network requests
+
+> TODO: Add content

doc/development/new_fe_guide/development/performance.md

+# Performance
+
+> TODO: Add content

doc/development/new_fe_guide/development/security.md

+# Security
+
+> TODO: Add content

doc/development/new_fe_guide/development/testing.md

+# Testing
+
+> TODO: Add content

doc/development/new_fe_guide/index.md

+# Frontend Development Guidelines
+
+This guide contains all the information to successfully contribute to GitLab's frontend.
+This is a living document, and we welcome contributions, feedback and suggestions.
+
+## [Principles](principles.md)
+
+Ensure that your frontend contribution starts off in the right direction.
+
+## [Initiatives](initiatives.md)
+
+High level overview of where we are going from a frontend perspective.
+
+## [Development](development/index.md)
+
+Guidance on topics related to development.
+
+## [Dependencies](dependencies.md)
+
+Learn about all the dependencies that make up our frontend, including some of our own custom built libraries.
+
+## [Style](style/index.md)
+
+Style guides to keep our code consistent.
+
+## [Tips](tips.md)
+
+Tips from our frontend team to develop more efficiently and effectively.

doc/development/new_fe_guide/initiatives.md

+# Initiatives
+
+> TODO: Add Initiatives

doc/development/new_fe_guide/principles.md

+# Principles
+
+> TODO: Add principles

doc/development/new_fe_guide/style/html.md

+# HTML style guide
+
+> TODO: Add content

doc/development/new_fe_guide/style/index.md

+# Style
+
+## [HTML style guide](html.md)
+
+## [SCSS style guide](scss.md)
+
+## [JavaScript style guide](javascript.md)
+
+## [Vue style guide](vue.md)

doc/development/new_fe_guide/style/javascript.md

+# JavaScript style guide
+
+> TODO: Add content

doc/development/new_fe_guide/style/scss.md

+# SCSS style guide
+
+> TODO: Add content

doc/development/new_fe_guide/style/vue.md

+# Vue style guide
+
+> TODO: Add content

doc/development/new_fe_guide/tips.md

+# Tips
+
+> TODO: Add tips

doc/user/project/clusters/index.md

@@ -109,6 +109,41 @@ you will be notified.
 You can now proceed to install some pre-defined applications and then
 enable the Kubernetes cluster integration.
 
+## Security implications
+
+CAUTION: **Important:**
+The whole cluster security is based on a model where [developers](../../permissions.md)
+are trusted, so **only trusted users should be allowed to control your clusters**.
+
+The default cluster configuration grants access to a wide set of
+functionalities needed to successfully build and deploy a containerized
+application. Bare in mind that the same credentials are used for all the
+applications running on the cluster.
+
+When GitLab creates the cluster, it enables and uses the legacy
+[Attribute-based access control (ABAC)](https://kubernetes.io/docs/admin/authorization/abac/).
+The newer [RBAC](https://kubernetes.io/docs/admin/authorization/rbac/)
+authorization will be supported in a
+[future release](https://gitlab.com/gitlab-org/gitlab-ce/issues/29398).
+
+### Security of GitLab Runners
+
+GitLab Runners have the [privileged mode](https://docs.gitlab.com/runner/executors/docker.html#the-privileged-mode)
+enabled by default, which allows them to execute special commands and running
+Docker in Docker. This functionality is needed to run some of the [Auto DevOps]
+jobs. This implies the containers are running in privileged mode and you should,
+therefore, be aware of some important details.
+
+The privileged flag gives all capabilities to the running container, which in
+turn can do almost everything that the host can do. Be aware of the
+inherent security risk associated with performing `docker run` operations on
+arbitrary images as they effectively have root access.
+
+If you don't want to use GitLab Runner in privileged mode, first make sure that
+you don't have it installed via the applications, and then use the
+[Runner's Helm chart](../../../install/kubernetes/gitlab_runner_chart.md) to
+install it manually.
+
 ## Installing applications
 
 GitLab provides a one-click install for various applications which will be
@@ -118,16 +153,16 @@ added directly to your configured cluster. Those applications are needed for
 | Application | GitLab version | Description |
 | ----------- | :------------: | ----------- |
 | [Helm Tiller](https://docs.helm.sh/) | 10.2+ | Helm is a package manager for Kubernetes and is required to install all the other applications. It will be automatically installed as a dependency when you try to install a different app. It is installed in its own pod inside the cluster which can run the `helm` CLI in a safe environment. |
-| [Ingress](https://kubernetes.io/docs/concepts/services-networking/ingress/) | 10.2+ | Ingress can provide load balancing, SSL termination, and name-based virtual hosting. It acts as a web proxy for your applications and is useful if you want to use [Auto DevOps](../../../topics/autodevops/index.md) or deploy your own web apps. |
+| [Ingress](https://kubernetes.io/docs/concepts/services-networking/ingress/) | 10.2+ | Ingress can provide load balancing, SSL termination, and name-based virtual hosting. It acts as a web proxy for your applications and is useful if you want to use [Auto DevOps] or deploy your own web apps. |
 | [Prometheus](https://prometheus.io/docs/introduction/overview/) | 10.4+ | Prometheus is an open-source monitoring and alerting system useful to supervise your deployed applications |
-| [GitLab Runner](https://docs.gitlab.com/runner/) | 10.6+ | GitLab Runner is the open source project that is used to run your jobs and send the results back to GitLab. It is used in conjunction with [GitLab CI](https://about.gitlab.com/features/gitlab-ci-cd/), the open-source continuous integration service included with GitLab that coordinates the jobs. |
+| [GitLab Runner](https://docs.gitlab.com/runner/) | 10.6+ | GitLab Runner is the open source project that is used to run your jobs and send the results back to GitLab. It is used in conjunction with [GitLab CI/CD](https://about.gitlab.com/features/gitlab-ci-cd/), the open-source continuous integration service included with GitLab that coordinates the jobs. When installing the GitLab Runner via the applications, it will run in **privileged mode** by default. Make sure you read the [security implications](#security-implications) before doing so. |
 
 ## Getting the external IP address
 
 NOTE: **Note:**
 You need a load balancer installed in your cluster in order to obtain the
 external IP address with the following procedure. It can be deployed using the
-[**Ingress** application](#installing-appplications).
+[**Ingress** application](#installing-applications).
 
 In order to publish your web application, you first need to find the external IP
 address associated to your load balancer.
@@ -329,3 +364,4 @@ the deployment variables above, ensuring any pods you create are labelled with
 
 [permissions]: ../../permissions.md
 [ee]: https://about.gitlab.com/products/
+[Auto DevOps]: ../../../topics/autodevops/index.md

doc/user/project/merge_requests/index.md

@@ -28,6 +28,7 @@ With GitLab merge requests, you can:
 - Enable [fast-forward merge requests](#fast-forward-merge-requests)
 - Enable [semi-linear history merge requests](#semi-linear-history-merge-requests) as another security layer to guarantee the pipeline is passing in the target branch
 - [Create new merge requests by email](#create-new-merge-requests-by-email)
+- Allow maintainers of the target project to push directly to the fork by [allowing edits from maintainers](maintainer_access.md)
 
 With **[GitLab Enterprise Edition][ee]**, you can also:
 

doc/user/project/merge_requests/maintainer_access.md

+# Allow maintainer pushes for merge requests across forks
+
+This feature is available for merge requests across forked projects that are
+publicly accessible. It makes it easier for maintainers of projects to collaborate
+on merge requests across forks.
+
+When enabling this feature for a merge request, you give can give members with push access to the target project rights to edit files on the source branch of the merge request.
+
+The feature can only be enabled by users who already have push access to the source project. And only lasts while the merge request is open.
+
+Enable this functionality while creating a merge request:
+
+![Enable maintainer edits](./img/allow_maintainer_push.png)

lib/api/entities.rb

@@ -549,6 +549,7 @@ module API
       expose :discussion_locked
       expose :should_remove_source_branch?, as: :should_remove_source_branch
       expose :force_remove_source_branch?, as: :force_remove_source_branch
+      expose :allow_maintainer_to_push, if: -> (merge_request, _) { merge_request.for_fork? }
 
       expose :web_url do |merge_request, options|
         Gitlab::UrlBuilder.build(merge_request)

lib/api/merge_requests.rb

@@ -146,6 +146,7 @@ module API
           optional :milestone_id, type: Integer, desc: 'The ID of a milestone to assign the merge request'
           optional :labels, type: String, desc: 'Comma-separated list of label names'
           optional :remove_source_branch, type: Boolean, desc: 'Remove source branch when merging'
+          optional :allow_maintainer_to_push, type: Boolean, desc: 'Whether a maintainer of the target project can push to the source project'
 
           use :optional_params_ee
         end

lib/gitlab/checks/change_access.rb

@@ -49,7 +49,7 @@ module Gitlab
       protected
 
       def push_checks
-        if user_access.cannot_do_action?(:push_code)
+        unless can_push?
           raise GitAccess::UnauthorizedError, ERROR_MESSAGES[:push_code]
         end
       end
@@ -185,6 +185,11 @@ module Gitlab
       def commits
         @commits ||= project.repository.new_commits(newrev)
       end
+
+      def can_push?
+        user_access.can_do_action?(:push_code) ||
+          user_access.can_push_to_branch?(branch_name)
+      end
     end
   end
 end

lib/gitlab/git/repository.rb

@@ -1447,12 +1447,12 @@ module Gitlab
         end
       end
 
-      def last_commit_id_for_path(sha, path)
+      def last_commit_for_path(sha, path)
         gitaly_migrate(:last_commit_for_path) do |is_enabled|
           if is_enabled
-            last_commit_for_path_by_gitaly(sha, path).id
+            last_commit_for_path_by_gitaly(sha, path)
           else
-            last_commit_id_for_path_by_shelling_out(sha, path)
+            last_commit_for_path_by_rugged(sha, path)
           end
         end
       end
@@ -1900,7 +1900,7 @@ module Gitlab
       end
 
       def last_commit_for_path_by_rugged(sha, path)
-        sha = last_commit_id_for_path(sha, path)
+        sha = last_commit_id_for_path_by_shelling_out(sha, path)
         commit(sha)
       end
 

lib/gitlab/user_access.rb

@@ -63,13 +63,12 @@ module Gitlab
 
     request_cache def can_push_to_branch?(ref)
       return false unless can_access_git?
+      return false unless user.can?(:push_code, project) || project.branch_allows_maintainer_push?(user, ref)
 
       if protected?(ProtectedBranch, project, ref)
-        return true if project.user_can_push_to_empty_repo?(user)
-
-        protected_branch_accessible_to?(ref, action: :push)
+        project.user_can_push_to_empty_repo?(user) || protected_branch_accessible_to?(ref, action: :push)
       else
-        user.can?(:push_code, project)
+        true
       end
     end
 

spec/features/merge_request/maintainer_edits_fork_spec.rb

+require 'spec_helper'
+
+describe 'a maintainer edits files on a source-branch of an MR from a fork', :js do
+  include ProjectForksHelper
+  let(:user) { create(:user, username: 'the-maintainer') }
+  let(:target_project) { create(:project, :public, :repository) }
+  let(:author) { create(:user, username: 'mr-authoring-machine') }
+  let(:source_project) { fork_project(target_project, author, repository: true) }
+
+  let(:merge_request) do
+    create(:merge_request,
+           source_project: source_project,
+           target_project: target_project,
+           source_branch: 'fix',
+           target_branch: 'master',
+           author: author,
+           allow_maintainer_to_push: true)
+  end
+
+  before do
+    target_project.add_master(user)
+    sign_in(user)
+
+    visit project_merge_request_path(target_project, merge_request)
+    click_link 'Changes'
+    wait_for_requests
+    first('.js-file-title').click_link 'Edit'
+    wait_for_requests
+  end
+
+  it 'mentions commits will go to the source branch' do
+    expect(page).to have_content('Your changes can be committed to fix because a merge request is open.')
+  end
+
+  it 'allows committing to the source branch' do
+    find('.ace_text-input', visible: false).send_keys('Updated the readme')
+
+    click_button 'Commit changes'
+    wait_for_requests
+
+    expect(page).to have_content('Your changes have been successfully committed')
+    expect(page).to have_content('Updated the readme')
+  end
+end

spec/features/merge_request/user_allows_a_maintainer_to_push_spec.rb

+require 'spec_helper'
+
+describe 'create a merge request that allows maintainers to push', :js do
+  include ProjectForksHelper
+  let(:user) { create(:user) }
+  let(:target_project) { create(:project, :public, :repository) }
+  let(:source_project) { fork_project(target_project, user, repository: true, namespace: user.namespace) }
+
+  def visit_new_merge_request
+    visit project_new_merge_request_path(
+      source_project,
+      merge_request: {
+        source_project_id: source_project.id,
+        target_project_id: target_project.id,
+        source_branch: 'fix',
+        target_branch: 'master'
+      })
+  end
+
+  before do
+    sign_in(user)
+  end
+
+  it 'allows setting maintainer push possible' do
+    visit_new_merge_request
+
+    check 'Allow edits from maintainers'
+
+    click_button 'Submit merge request'
+
+    wait_for_requests
+
+    expect(page).to have_content('Allows edits from maintainers')
+  end
+
+  it 'shows a message when one of the projects is private' do
+    source_project.update!(visibility_level: Gitlab::VisibilityLevel::PRIVATE)
+
+    visit_new_merge_request
+
+    expect(page).to have_content('Not available for private projects')
+  end
+
+  it 'shows a message when the source branch is protected' do
+    create(:protected_branch, project: source_project, name: 'fix')
+
+    visit_new_merge_request
+
+    expect(page).to have_content('Not available for protected branches')
+  end
+
+  context 'when the merge request is being created within the same project' do
+    let(:source_project) { target_project }
+
+    it 'hides the checkbox if the merge request is being created within the same project' do
+      target_project.add_developer(user)
+
+      visit_new_merge_request
+
+      expect(page).not_to have_content('Allows edits from maintainers')
+    end
+  end
+
+  context 'when a maintainer tries to edit the option' do
+    let(:maintainer) { create(:user) }
+    let(:merge_request) do
+      create(:merge_request,
+             source_project: source_project,
+             target_project: target_project,
+             source_branch: 'fixes')
+    end
+
+    before do
+      target_project.add_master(maintainer)
+
+      sign_in(maintainer)
+    end
+
+    it 'it hides the option from maintainers' do
+      visit edit_project_merge_request_path(target_project, merge_request)
+
+      expect(page).not_to have_content('Allows edits from maintainers')
+    end
+  end
+end

spec/features/projects/user_creates_files_spec.rb

@@ -133,13 +133,20 @@ describe 'User creates files' do
       before do
         project2.add_reporter(user)
         visit(project2_tree_path_root_ref)
-      end
 
-      it 'creates and commit new file in forked project', :js do
         find('.add-to-tree').click
         click_link('New file')
+      end
+
+      it 'shows a message saying the file will be committed in a fork' do
+        message = "A new branch will be created in your fork and a new merge request will be started."
 
+        expect(page).to have_content(message)
+      end
+
+      it 'creates and commit new file in forked project', :js do
         expect(page).to have_selector('.file-editor')
+        expect(page).to have_content
 
         find('#editor')
         execute_script("ace.edit('editor').setValue('*.rbca')")

spec/fixtures/api/schemas/entities/merge_request_basic.json

@@ -12,7 +12,8 @@
     "rebase_in_progress": { "type": "boolean" },
     "assignee_id": { "type": ["integer", "null"] },
     "subscribed": { "type": ["boolean", "null"] },
-    "participants": { "type": "array" }
+    "participants": { "type": "array" },
+    "allow_maintainer_to_push": { "type": "boolean"}
   },
   "additionalProperties": false
 }

spec/fixtures/api/schemas/entities/merge_request_widget.json

@@ -30,6 +30,7 @@
     "source_project_id": { "type": "integer" },
     "target_branch": { "type": "string" },
     "target_project_id": { "type": "integer" },
+    "allow_maintainer_to_push": { "type": "boolean"},
     "metrics": {
       "oneOf": [
         { "type": "null" },

spec/fixtures/api/schemas/public_api/v4/merge_requests.json

@@ -82,7 +82,8 @@
         "total_time_spent": { "type": "integer" },
         "human_time_estimate": { "type": ["string", "null"] },
         "human_total_time_spent": { "type": ["string", "null"] }
-      }
+      },
+      "allow_maintainer_to_push": { "type": ["boolean", "null"] }
     },
     "required": [
       "id", "iid", "project_id", "title", "description",

spec/helpers/tree_helper_spec.rb

@@ -62,4 +62,13 @@ describe TreeHelper do
       end
     end
   end
+
+  describe '#commit_in_single_accessible_branch' do
+    it 'escapes HTML from the branch name' do
+      helper.instance_variable_set(:@branch_name, "<script>alert('escape me!');</script>")
+      escaped_branch_name = '&lt;script&gt;alert(&#39;escape me!&#39;);&lt;/script&gt;'
+
+      expect(helper.commit_in_single_accessible_branch).to include(escaped_branch_name)
+    end
+  end
 end

spec/javascripts/prometheus_metrics/prometheus_metrics_spec.js

@@ -85,7 +85,7 @@ describe('PrometheusMetrics', () => {
       expect(prometheusMetrics.$monitoredMetricsLoading.hasClass('hidden')).toBeTruthy();
       expect(prometheusMetrics.$monitoredMetricsList.hasClass('hidden')).toBeFalsy();
 
-      expect(prometheusMetrics.$monitoredMetricsCount.text()).toEqual('12');
+      expect(prometheusMetrics.$monitoredMetricsCount.text()).toEqual('3 exporters with 12 metrics were found');
       expect($metricsListLi.length).toEqual(metrics.length);
       expect($metricsListLi.first().find('.badge').text()).toEqual(`${metrics[0].active_metrics}`);
     });

spec/javascripts/vue_mr_widget/components/mr_widget_maintainer_edit_spec.js

+import Vue from 'vue';
+import maintainerEditComponent from '~/vue_merge_request_widget/components/mr_widget_maintainer_edit.vue';
+import mountComponent from 'spec/helpers/vue_mount_component_helper';
+
+describe('RWidgetMaintainerEdit', () => {
+  let Component;
+  let vm;
+
+  beforeEach(() => {
+    Component = Vue.extend(maintainerEditComponent);
+  });
+
+  afterEach(() => {
+    vm.$destroy();
+  });
+
+  describe('when a maintainer is allowed to edit', () => {
+    beforeEach(() => {
+      vm = mountComponent(Component, {
+        maintainerEditAllowed: true,
+      });
+    });
+
+    it('it renders the message', () => {
+      expect(vm.$el.textContent.trim()).toEqual('Allows edits from maintainers');
+    });
+  });
+
+  describe('when a maintainer is not allowed to edit', () => {
+    beforeEach(() => {
+      vm = mountComponent(Component, {
+        maintainerEditAllowed: false,
+      });
+    });
+
+    it('hides the message', () => {
+      expect(vm.$el.textContent.trim()).toEqual('');
+    });
+  });
+});

spec/javascripts/vue_mr_widget/mr_widget_options_spec.js

@@ -349,6 +349,7 @@ describe('mrWidgetOptions', () => {
       expect(comps['mr-widget-pipeline-blocked']).toBeDefined();
       expect(comps['mr-widget-pipeline-failed']).toBeDefined();
       expect(comps['mr-widget-merge-when-pipeline-succeeds']).toBeDefined();
+      expect(comps['mr-widget-maintainer-edit']).toBeDefined();
     });
   });
 

spec/lib/gitlab/checks/change_access_spec.rb

@@ -30,9 +30,10 @@ describe Gitlab::Checks::ChangeAccess do
       end
     end
 
-    context 'when the user is not allowed to push code' do
+    context 'when the user is not allowed to push to the repo' do
       it 'raises an error' do
         expect(user_access).to receive(:can_do_action?).with(:push_code).and_return(false)
+        expect(user_access).to receive(:can_push_to_branch?).with('master').and_return(false)
 
         expect { subject.exec }.to raise_error(Gitlab::GitAccess::UnauthorizedError, 'You are not allowed to push code to this project.')
       end

spec/lib/gitlab/import_export/all_models.yml

@@ -311,6 +311,7 @@ project:
 - custom_attributes
 - lfs_file_locks
 - project_badges
+- source_of_merge_requests
 award_emoji:
 - awardable
 - user

spec/lib/gitlab/import_export/safe_model_attributes.yml

@@ -172,6 +172,7 @@ MergeRequest:
 - last_edited_by_id
 - head_pipeline_id
 - discussion_locked
+- allow_maintainer_to_push
 MergeRequestDiff:
 - id
 - state

spec/lib/gitlab/user_access_spec.rb

 require 'spec_helper'
 
 describe Gitlab::UserAccess do
+  include ProjectForksHelper
+
   let(:access) { described_class.new(user, project: project) }
   let(:project) { create(:project, :repository) }
   let(:user) { create(:user) }
@@ -118,6 +120,39 @@ describe Gitlab::UserAccess do
       end
     end
 
+    describe 'allowing pushes to maintainers of forked projects' do
+      let(:canonical_project) { create(:project, :public, :repository) }
+      let(:project) { fork_project(canonical_project, create(:user), repository: true) }
+
+      before do
+        create(
+          :merge_request,
+          target_project: canonical_project,
+          source_project: project,
+          source_branch: 'awesome-feature',
+          allow_maintainer_to_push: true
+        )
+      end
+
+      it 'allows users that have push access to the canonical project to push to the MR branch' do
+        canonical_project.add_developer(user)
+
+        expect(access.can_push_to_branch?('awesome-feature')).to be_truthy
+      end
+
+      it 'does not allow the user to push to other branches' do
+        canonical_project.add_developer(user)
+
+        expect(access.can_push_to_branch?('master')).to be_falsey
+      end
+
+      it 'does not allow the user to push if he does not have push access to the canonical project' do
+        canonical_project.add_guest(user)
+
+        expect(access.can_push_to_branch?('awesome-feature')).to be_falsey
+      end
+    end
+
     describe 'merge to protected branch if allowed for developers' do
       before do
         @branch = create :protected_branch, :developers_can_merge, project: project

spec/models/merge_request_spec.rb

@@ -2566,4 +2566,82 @@ describe MergeRequest do
       it_behaves_like 'checking whether a rebase is in progress'
     end
   end
+
+  describe '#allow_maintainer_to_push' do
+    let(:merge_request) do
+      build(:merge_request, source_branch: 'fixes', allow_maintainer_to_push: true)
+    end
+
+    it 'is false when pushing by a maintainer is not possible' do
+      expect(merge_request).to receive(:maintainer_push_possible?) { false }
+
+      expect(merge_request.allow_maintainer_to_push).to be_falsy
+    end
+
+    it 'is true when pushing by a maintainer is possible' do
+      expect(merge_request).to receive(:maintainer_push_possible?) { true }
+
+      expect(merge_request.allow_maintainer_to_push).to be_truthy
+    end
+  end
+
+  describe '#maintainer_push_possible?' do
+    let(:merge_request) do
+      build(:merge_request, source_branch: 'fixes')
+    end
+
+    before do
+      allow(ProtectedBranch).to receive(:protected?) { false }
+    end
+
+    it 'does not allow maintainer to push if the source project is the same as the target' do
+      merge_request.target_project = merge_request.source_project = create(:project, :public)
+
+      expect(merge_request.maintainer_push_possible?).to be_falsy
+    end
+
+    it 'allows maintainer to push when both source and target are public' do
+      merge_request.target_project = build(:project, :public)
+      merge_request.source_project = build(:project, :public)
+
+      expect(merge_request.maintainer_push_possible?).to be_truthy
+    end
+
+    it 'is not available for protected branches' do
+      merge_request.target_project = build(:project, :public)
+      merge_request.source_project = build(:project, :public)
+
+      expect(ProtectedBranch).to receive(:protected?)
+                                   .with(merge_request.source_project, 'fixes')
+                                   .and_return(true)
+
+      expect(merge_request.maintainer_push_possible?).to be_falsy
+    end
+  end
+
+  describe '#can_allow_maintainer_to_push?' do
+    let(:target_project) { create(:project, :public) }
+    let(:source_project) { fork_project(target_project) }
+    let(:merge_request) do
+      create(:merge_request,
+             source_project: source_project,
+             source_branch: 'fixes',
+             target_project: target_project)
+    end
+    let(:user) { create(:user) }
+
+    before do
+      allow(merge_request).to receive(:maintainer_push_possible?) { true }
+    end
+
+    it 'is false if the user does not have push access to the source project' do
+      expect(merge_request.can_allow_maintainer_to_push?(user)).to be_falsy
+    end
+
+    it 'is true when the user has push access to the source project' do
+      source_project.add_developer(user)
+
+      expect(merge_request.can_allow_maintainer_to_push?(user)).to be_truthy
+    end
+  end
 end

spec/models/project_spec.rb

 require 'spec_helper'
 
 describe Project do
+  include ProjectForksHelper
+
   describe 'associations' do
     it { is_expected.to belong_to(:group) }
     it { is_expected.to belong_to(:namespace) }
@@ -3812,4 +3814,103 @@ describe Project do
       end
     end
   end
+
+  context 'with cross project merge requests' do
+    let(:user) { create(:user) }
+    let(:target_project) { create(:project, :repository) }
+    let(:project) { fork_project(target_project, nil, repository: true) }
+    let!(:merge_request) do
+      create(
+        :merge_request,
+        target_project: target_project,
+        target_branch: 'target-branch',
+        source_project: project,
+        source_branch: 'awesome-feature-1',
+        allow_maintainer_to_push: true
+      )
+    end
+
+    before do
+      target_project.add_developer(user)
+    end
+
+    describe '#merge_requests_allowing_push_to_user' do
+      it 'returns open merge requests for which the user has developer access to the target project' do
+        expect(project.merge_requests_allowing_push_to_user(user)).to include(merge_request)
+      end
+
+      it 'does not include closed merge requests' do
+        merge_request.close
+
+        expect(project.merge_requests_allowing_push_to_user(user)).to be_empty
+      end
+
+      it 'does not include merge requests for guest users' do
+        guest = create(:user)
+        target_project.add_guest(guest)
+
+        expect(project.merge_requests_allowing_push_to_user(guest)).to be_empty
+      end
+
+      it 'does not include the merge request for other users' do
+        other_user = create(:user)
+
+        expect(project.merge_requests_allowing_push_to_user(other_user)).to be_empty
+      end
+
+      it 'is empty when no user is passed' do
+        expect(project.merge_requests_allowing_push_to_user(nil)).to be_empty
+      end
+    end
+
+    describe '#branch_allows_maintainer_push?' do
+      it 'allows access if the user can merge the merge request' do
+        expect(project.branch_allows_maintainer_push?(user, 'awesome-feature-1'))
+          .to be_truthy
+      end
+
+      it 'does not allow guest users access' do
+        guest = create(:user)
+        target_project.add_guest(guest)
+
+        expect(project.branch_allows_maintainer_push?(guest, 'awesome-feature-1'))
+          .to be_falsy
+      end
+
+      it 'does not allow access to branches for which the merge request was closed' do
+        create(:merge_request, :closed,
+               target_project: target_project,
+               target_branch: 'target-branch',
+               source_project: project,
+               source_branch: 'rejected-feature-1',
+               allow_maintainer_to_push: true)
+
+        expect(project.branch_allows_maintainer_push?(user, 'rejected-feature-1'))
+          .to be_falsy
+      end
+
+      it 'does not allow access if the user cannot merge the merge request' do
+        create(:protected_branch, :masters_can_push, project: target_project, name: 'target-branch')
+
+        expect(project.branch_allows_maintainer_push?(user, 'awesome-feature-1'))
+          .to be_falsy
+      end
+
+      it 'caches the result' do
+        control = ActiveRecord::QueryRecorder.new { project.branch_allows_maintainer_push?(user, 'awesome-feature-1') }
+
+        expect { 3.times { project.branch_allows_maintainer_push?(user, 'awesome-feature-1') } }
+          .not_to exceed_query_limit(control)
+      end
+
+      context 'when the requeststore is active', :request_store do
+        it 'only queries per project across instances' do
+          control = ActiveRecord::QueryRecorder.new { project.branch_allows_maintainer_push?(user, 'awesome-feature-1') }
+
+          expect { 2.times { described_class.find(project.id).branch_allows_maintainer_push?(user, 'awesome-feature-1') } }
+            .not_to exceed_query_limit(control).with_threshold(2)
+        end
+      end
+    end
+  end
 end

spec/policies/project_policy_spec.rb

@@ -308,6 +308,7 @@ describe ProjectPolicy do
   it_behaves_like 'project policies as owner'
   it_behaves_like 'project policies as admin'
 
+<<<<<<< HEAD
   context 'EE' do
     let(:additional_guest_permissions)  { [:read_issue_link] }
     let(:additional_reporter_permissions) { [:admin_issue_link]}
@@ -358,6 +359,42 @@ describe ProjectPolicy do
           is_expected.to be_allowed(*auditor_permissions)
         end
       end
+=======
+  context 'when a public project has merge requests allowing access' do
+    include ProjectForksHelper
+    let(:user) { create(:user) }
+    let(:target_project) { create(:project, :public) }
+    let(:project) { fork_project(target_project) }
+    let!(:merge_request) do
+      create(
+        :merge_request,
+        target_project: target_project,
+        source_project: project,
+        allow_maintainer_to_push: true
+      )
+    end
+    let(:maintainer_abilities) do
+      %w(create_build update_build create_pipeline update_pipeline)
+    end
+
+    subject { described_class.new(user, project) }
+
+    it 'does not allow pushing code' do
+      expect_disallowed(*maintainer_abilities)
+    end
+
+    it 'allows pushing if the user is a member with push access to the target project' do
+      target_project.add_developer(user)
+
+      expect_allowed(*maintainer_abilities)
+    end
+
+    it 'dissallows abilities to a maintainer if the merge request was closed' do
+      target_project.add_developer(user)
+      merge_request.close!
+
+      expect_disallowed(*maintainer_abilities)
+>>>>>>> upstream/master
     end
   end
 end

spec/requests/api/merge_requests_spec.rb

@@ -617,6 +617,25 @@ describe API::MergeRequests do
         expect(json_response['changes_count']).to eq('5+')
       end
     end
+
+    context 'for forked projects' do
+      let(:user2) { create(:user) }
+      let(:project) { create(:project, :public, :repository) }
+      let(:forked_project) { fork_project(project, user2, repository: true) }
+      let(:merge_request) do
+        create(:merge_request,
+               source_project: forked_project,
+               target_project: project,
+               source_branch: 'fixes',
+               allow_maintainer_to_push: true)
+      end
+
+      it 'includes the `allow_maintainer_to_push` field' do
+        get api("/projects/#{project.id}/merge_requests/#{merge_request.iid}", user)
+
+        expect(json_response['allow_maintainer_to_push']).to be_truthy
+      end
+    end
   end
 
   describe 'GET /projects/:id/merge_requests/:merge_request_iid/participants' do
@@ -818,6 +837,7 @@ describe API::MergeRequests do
 
     context 'forked projects' do
       let!(:user2) { create(:user) }
+      let(:project) { create(:project, :public, :repository) }
       let!(:forked_project) { fork_project(project, user2, repository: true) }
       let!(:unrelated_project) { create(:project,  namespace: create(:user).namespace, creator_id: user2.id) }
 
@@ -875,6 +895,14 @@ describe API::MergeRequests do
         expect(response).to have_gitlab_http_status(400)
       end
 
+      it 'allows setting `allow_maintainer_to_push`' do
+        post api("/projects/#{forked_project.id}/merge_requests", user2),
+          title: 'Test merge_request', source_branch: "feature_conflict", target_branch: "master",
+          author: user2, target_project_id: project.id, allow_maintainer_to_push: true
+        expect(response).to have_gitlab_http_status(201)
+        expect(json_response['allow_maintainer_to_push']).to be_truthy
+      end
+
       context 'when target_branch and target_project_id is specified' do
         let(:params) do
           { title: 'Test merge_request',

spec/services/merge_requests/update_service_spec.rb

 require 'spec_helper'
 
 describe MergeRequests::UpdateService, :mailer do
+  include ProjectForksHelper
+
   let(:project) { create(:project, :repository) }
   let(:user) { create(:user) }
   let(:user2) { create(:user) }
@@ -630,5 +632,40 @@ describe MergeRequests::UpdateService, :mailer do
       let(:open_issuable) { merge_request }
       let(:closed_issuable) { create(:closed_merge_request, source_project: project) }
     end
+
+    context 'setting `allow_maintainer_to_push`' do
+      let(:target_project) { create(:project, :public) }
+      let(:source_project) { fork_project(target_project) }
+      let(:user) { create(:user) }
+      let(:merge_request) do
+        create(:merge_request,
+               source_project: source_project,
+               source_branch: 'fixes',
+               target_project: target_project)
+      end
+
+      before do
+        allow(ProtectedBranch).to receive(:protected?).with(source_project, 'fixes') { false }
+      end
+
+      it 'does not allow a maintainer of the target project to set `allow_maintainer_to_push`' do
+        target_project.add_developer(user)
+
+        update_merge_request(allow_maintainer_to_push: true, title: 'Updated title')
+
+        expect(merge_request.title).to eq('Updated title')
+        expect(merge_request.allow_maintainer_to_push).to be_falsy
+      end
+
+      it 'is allowed by a user that can push to the source and can update the merge request' do
+        merge_request.update!(assignee: user)
+        source_project.add_developer(user)
+
+        update_merge_request(allow_maintainer_to_push: true, title: 'Updated title')
+
+        expect(merge_request.title).to eq('Updated title')
+        expect(merge_request.allow_maintainer_to_push).to be_truthy
+      end
+    end
   end
 end

spec/views/projects/tree/show.html.haml_spec.rb

@@ -13,6 +13,7 @@ describe 'projects/tree/show' do
 
     allow(view).to receive(:can?).and_return(true)
     allow(view).to receive(:can_collaborate_with_project?).and_return(true)
+    allow(view).to receive_message_chain('user_access.can_push_to_branch?').and_return(true)
     allow(view).to receive(:current_application_settings).and_return(Gitlab::CurrentSettings.current_application_settings)
   end