Allow a user to select `allow maintainer to push`

When a project is not private, and the source branch not protected the
user can now select the option to allow maintainers to push to this
branch

8 files changed, 228 insertions, 1 deletions

diff --git a/spec/features/merge_request/user_allows_a_maintainer_to_push_spec.rb b/spec/features/merge_request/user_allows_a_maintainer_to_push_spec.rb
new file mode 100644
index 00000000000..eb41d7de8ed
--- /dev/null
+++ b/spec/features/merge_request/user_allows_a_maintainer_to_push_spec.rb
@@ -0,0 +1,85 @@
+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
diff --git a/spec/fixtures/api/schemas/entities/merge_request_basic.json b/spec/fixtures/api/schemas/entities/merge_request_basic.json
index f1199468d53..46031961cca 100644
--- a/spec/fixtures/api/schemas/entities/merge_request_basic.json
+++ b/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
 }
diff --git a/spec/fixtures/api/schemas/entities/merge_request_widget.json b/spec/fixtures/api/schemas/entities/merge_request_widget.json
index cfbeec58a45..a622bf88b13 100644
--- a/spec/fixtures/api/schemas/entities/merge_request_widget.json
+++ b/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" },
diff --git a/spec/javascripts/vue_mr_widget/components/mr_widget_maintainer_edit_spec.js b/spec/javascripts/vue_mr_widget/components/mr_widget_maintainer_edit_spec.js
new file mode 100644
index 00000000000..65b3f721281
--- /dev/null
+++ b/spec/javascripts/vue_mr_widget/components/mr_widget_maintainer_edit_spec.js
@@ -0,0 +1,23 @@
+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('MRWidgetAuthor', () => {
+  let vm;
+
+  beforeEach(() => {
+    const Component = Vue.extend(maintainerEditComponent);
+
+    vm = mountComponent(Component, {
+      maintainerEditAllowed: true,
+    });
+  });
+
+  afterEach(() => {
+    vm.$destroy();
+  });
+
+  it('renders the message when maintainers are allowed to edit', () => {
+    expect(vm.$el.textContent.trim()).toEqual('Allows edits from maintainers');
+  });
+});
diff --git a/spec/javascripts/vue_mr_widget/mr_widget_options_spec.js b/spec/javascripts/vue_mr_widget/mr_widget_options_spec.js
index 18ba34b55a5..ebe151ac3b1 100644
--- a/spec/javascripts/vue_mr_widget/mr_widget_options_spec.js
+++ b/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();
     });
   });
 
diff --git a/spec/lib/gitlab/import_export/safe_model_attributes.yml b/spec/lib/gitlab/import_export/safe_model_attributes.yml
index ddcbb7a0033..0b938892da5 100644
--- a/spec/lib/gitlab/import_export/safe_model_attributes.yml
+++ b/spec/lib/gitlab/import_export/safe_model_attributes.yml
@@ -168,6 +168,7 @@ MergeRequest:
 - last_edited_by_id
 - head_pipeline_id
 - discussion_locked
+- allow_maintainer_to_push
 MergeRequestDiff:
 - id
 - state
diff --git a/spec/models/merge_request_spec.rb b/spec/models/merge_request_spec.rb
index 243eeddc7a8..7986aa31e16 100644
--- a/spec/models/merge_request_spec.rb
+++ b/spec/models/merge_request_spec.rb
@@ -2084,4 +2084,82 @@ 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
diff --git a/spec/services/merge_requests/update_service_spec.rb b/spec/services/merge_requests/update_service_spec.rb
index c31259239ee..5279ea6164e 100644
--- a/spec/services/merge_requests/update_service_spec.rb
+++ b/spec/services/merge_requests/update_service_spec.rb
@@ -1,6 +1,8 @@
 require 'spec_helper'
 
 describe MergeRequests::UpdateService, :mailer do
+  include ProjectForksHelper
+
   let(:project) { create(:project, :repository) }
   let(:user) { create(:user) }
   let(:user2) { create(:user) }
@@ -538,5 +540,40 @@ 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