Introduce namespace license checks for rebase before merge

app/controllers/ee/projects/merge_requests_controller.rb

@@ -4,12 +4,13 @@ module EE
       extend ActiveSupport::Concern
 
       prepended do
-        # This module is prepended to `Projects::MergeRequstController`, which
+        # This module is prepended to `Projects::MergeRequestController`, which
         # already calls `before_action :merge_request, only: [...]`. Calling it
         # again here would *replace* the restriction, rather than extending it.
         before_action(only: [:approve, :approvals, :unapprove, :rebase]) { merge_request }
 
         before_action :set_suggested_approvers, only: [:new, :new_diffs, :edit]
+        before_action :check_merge_request_rebase_available!, only: [:rebase]
       end
 
       def rebase

app/models/ee/merge_request.rb

@@ -5,7 +5,9 @@ module EE
     end
 
     def should_be_rebased?
-      self.project.ff_merge_must_be_possible? && !ff_merge_possible?
+      project.feature_available?(:merge_request_rebase) &&
+        project.ff_merge_must_be_possible? &&
+        !ff_merge_possible?
     end
 
     def rebase_dir_path

app/models/license.rb

@@ -10,6 +10,7 @@ class License < ActiveRecord::Base
   ELASTIC_SEARCH_FEATURE = 'GitLab_ElasticSearch'.freeze
   RELATED_ISSUES_FEATURE = 'RelatedIssues'.freeze
   EXPORT_ISSUES_FEATURE  = 'GitLab_ExportIssues'.freeze
+  MERGE_REQUEST_REBASE_FEATURE = 'GitLab_MergeRequestRebase'.freeze
 
   FEATURE_CODES = {
     geo: GEO_FEATURE,
@@ -21,7 +22,8 @@ class License < ActiveRecord::Base
     # Features that make sense to Namespace:
     deploy_board: DEPLOY_BOARD_FEATURE,
     file_lock: FILE_LOCK_FEATURE,
-    export_issues: EXPORT_ISSUES_FEATURE
+    export_issues: EXPORT_ISSUES_FEATURE,
+    merge_request_rebase: MERGE_REQUEST_REBASE_FEATURE
   }.freeze
 
   STARTER_PLAN = 'starter'.freeze
@@ -32,7 +34,8 @@ class License < ActiveRecord::Base
   EES_FEATURES = [
     { ELASTIC_SEARCH_FEATURE => 1 },
     { RELATED_ISSUES_FEATURE => 1 },
-    { EXPORT_ISSUES_FEATURE => 1 }
+    { EXPORT_ISSUES_FEATURE => 1 },
+    { MERGE_REQUEST_REBASE_FEATURE => 1 }
   ].freeze
 
   EEP_FEATURES = [
@@ -65,7 +68,8 @@ class License < ActiveRecord::Base
     { AUDITOR_USER_FEATURE => 1 },
     { SERVICE_DESK_FEATURE => 1 },
     { OBJECT_STORAGE_FEATURE => 1 },
-    { EXPORT_ISSUES_FEATURE => 1 }
+    { EXPORT_ISSUES_FEATURE => 1 },
+    { MERGE_REQUEST_REBASE_FEATURE => 1 }
   ].freeze
 
   FEATURES_BY_PLAN = {

app/views/projects/ee/_merge_request_settings.html.haml

@@ -20,9 +20,10 @@
       %span.descr
         A merge commit is created for every merge, but merging is only allowed if fast-forward merge is possible.
         This way you could make sure that if this merge request would build, after merging to target branch it would also build.
-      %br
-      %span.descr
-        When fast-forward merge is not possible, the user is given the option to rebase.
+      - if project.feature_available?(:merge_request_rebase)
+        %br
+        %span.descr
+          When fast-forward merge is not possible, the user is given the option to rebase.
 
   .radio
     = label_tag :project_merge_method_ff do
@@ -31,9 +32,10 @@
       %br
       %span.descr
         No merge commits are created and all merges are fast-forwarded, which means that merging is only allowed if the branch could be fast-forwarded.
-      %br
-      %span.descr
-        When fast-forward merge is not possible, the user is given the option to rebase.
+      - if project.feature_available?(:merge_request_rebase)
+        %br
+        %span.descr
+          When fast-forward merge is not possible, the user is given the option to rebase.
 
 .form-group
   = form.label :merge_requests_template, class: 'label-light' do

changelogs/unreleased-ee/2570-namespace-rebase-before-merge.yml

+---
+title: Introduce namespace license checks for rebase before merge
+merge_request: 2200
+author:

spec/controllers/projects/merge_requests_controller_ee_spec.rb

 require 'spec_helper'
 
 describe Projects::MergeRequestsController do
-  let(:project) { create(:project) }
-  let(:user)    { project.owner }
+  let(:project)       { create(:project) }
   let(:merge_request) { create(:merge_request_with_diffs, target_project: project, source_project: project) }
+  let(:user)          { project.owner }
+  let(:viewer)        { user }
 
   before do
-    sign_in(user)
+    sign_in(viewer)
   end
 
   describe 'POST #create' do
@@ -347,4 +348,63 @@ describe Projects::MergeRequestsController do
       end
     end
   end
+
+  describe 'POST #rebase' do
+    def post_rebase
+      post :rebase, namespace_id: project.namespace, project_id: project, id: merge_request
+    end
+
+    def expect_rebase_worker
+      expect(RebaseWorker).to receive(:perform_async).with(merge_request.id, viewer.id)
+    end
+
+    context 'successfully' do
+      it 'enqeues a RebaseWorker' do
+        expect_rebase_worker
+
+        post_rebase
+
+        expect(response.status).to eq(200)
+      end
+    end
+
+    context 'approvals pending' do
+      let(:project) { create(:project, approvals_before_merge: 1) }
+
+      it 'returns 404' do
+        expect_rebase_worker.never
+
+        post_rebase
+
+        expect(response.status).to eq(404)
+      end
+    end
+
+    context 'user cannot merge' do
+      let(:viewer) { create(:user) }
+
+      before do
+        project.add_reporter(viewer)
+      end
+
+      it 'returns 404' do
+        expect_rebase_worker.never
+
+        post_rebase
+
+        expect(response.status).to eq(404)
+      end
+    end
+
+    context 'rebase unavailable in license' do
+      it 'returns 404' do
+        stub_licensed_features(merge_request_rebase: false)
+        expect_rebase_worker.never
+
+        post_rebase
+
+        expect(response.status).to eq(404)
+      end
+    end
+  end
 end

spec/models/ee/merge_request_spec.rb

 require 'spec_helper'
 
 describe MergeRequest, models: true do
-  subject { create(:merge_request) }
+  let(:project) { create(:project) }
+
+  subject(:merge_request) { create(:merge_request, source_project: project, target_project: project) }
+
+  describe '#should_be_rebased?' do
+    subject { merge_request.should_be_rebased? }
+
+    context 'project forbids rebase' do
+      it { is_expected.to be_falsy }
+    end
+
+    context 'project allows rebase' do
+      let(:project) { create(:project, merge_requests_rebase_enabled: true) }
+
+      it 'returns false when the project feature is unavailable' do
+        expect(merge_request.target_project).to receive(:feature_available?).with(:merge_request_rebase).and_return(false)
+
+        is_expected.to be_falsy
+      end
+
+      it 'returns true when the project feature is available' do
+        expect(merge_request.target_project).to receive(:feature_available?).with(:merge_request_rebase).and_return(true)
+
+        is_expected.to be_truthy
+      end
+    end
+  end
 
   describe '#rebase_in_progress?' do
     it 'returns true when there is a current rebase directory' do