Add an endpoint to create a new new branch and empty WIP MR from issue

6 files changed, 67 insertions, 1 deletions

diff --git a/app/controllers/projects/issues_controller.rb b/app/controllers/projects/issues_controller.rb
index cbf67137261..7cb6ab1bf09 100644
--- a/app/controllers/projects/issues_controller.rb
+++ b/app/controllers/projects/issues_controller.rb
@@ -11,7 +11,7 @@ class Projects::IssuesController < Projects::ApplicationController
   before_action :redirect_to_external_issue_tracker, only: [:index, :new]
   before_action :module_enabled
   before_action :issue, only: [:edit, :update, :show, :referenced_merge_requests,
-                               :related_branches, :can_create_branch, :rendered_title]
+                               :related_branches, :can_create_branch, :rendered_title, :create_merge_request]
 
   # Allow read any issue
   before_action :authorize_read_issue!, only: [:show, :rendered_title]
@@ -22,6 +22,9 @@ class Projects::IssuesController < Projects::ApplicationController
   # Allow modify issue
   before_action :authorize_update_issue!, only: [:edit, :update]
 
+  # Allow create a new branch and empty WIP merge request from current issue
+  before_action :authorize_create_merge_request!, only: [:create_merge_request]
+
   respond_to :html
 
   def index
@@ -201,6 +204,18 @@ class Projects::IssuesController < Projects::ApplicationController
     render json: { title: view_context.markdown_field(@issue, :title) }
   end
 
+  def create_merge_request
+    result = MergeRequests::CreateFromIssueService.new(project, current_user, issue_iid: issue.iid).execute
+
+    respond_to do |format|
+      if result[:status] == :success
+        format.json { render json: MergeRequestCreateSerializer.new.represent(result[:merge_request]) }
+      else
+        format.json { render json: result[:messsage], status: :unprocessable_entity }
+      end
+    end
+  end
+
   protected
 
   def issue
@@ -224,6 +239,10 @@ class Projects::IssuesController < Projects::ApplicationController
     return render_404 unless can?(current_user, :admin_issue, @project)
   end
 
+  def authorize_create_merge_request!
+    return render_404 unless can?(current_user, :push_code, @project) && @issue.can_be_worked_on?(current_user)
+  end
+
   def module_enabled
     return render_404 unless @project.feature_available?(:issues, current_user) && @project.default_issues_tracker?
   end
diff --git a/app/serializers/merge_request_create_entity.rb b/app/serializers/merge_request_create_entity.rb
new file mode 100644
index 00000000000..11234313293
--- /dev/null
+++ b/app/serializers/merge_request_create_entity.rb
@@ -0,0 +1,7 @@
+class MergeRequestCreateEntity < Grape::Entity
+  expose :iid
+
+  expose :url do |merge_request|
+    Gitlab::UrlBuilder.build(merge_request)
+  end
+end
diff --git a/app/serializers/merge_request_create_serializer.rb b/app/serializers/merge_request_create_serializer.rb
new file mode 100644
index 00000000000..08daf473319
--- /dev/null
+++ b/app/serializers/merge_request_create_serializer.rb
@@ -0,0 +1,3 @@
+class MergeRequestCreateSerializer < BaseSerializer
+  entity MergeRequestCreateEntity
+end
diff --git a/config/routes/project.rb b/config/routes/project.rb
index a15e365cc2f..956afe4faa3 100644
--- a/config/routes/project.rb
+++ b/config/routes/project.rb
@@ -234,6 +234,7 @@ constraints(ProjectUrlConstrainer.new) do
           get :related_branches
           get :can_create_branch
           get :rendered_title
+          post :create_merge_request
         end
         collection do
           post  :bulk_update
diff --git a/spec/controllers/projects/issues_controller_spec.rb b/spec/controllers/projects/issues_controller_spec.rb
index 79034b8d24d..5f1f892821a 100644
--- a/spec/controllers/projects/issues_controller_spec.rb
+++ b/spec/controllers/projects/issues_controller_spec.rb
@@ -756,4 +756,28 @@ describe Projects::IssuesController do
       expect(response).to have_http_status(200)
     end
   end
+
+  describe 'POST create_merge_request' do
+    before do
+      project.add_developer(user)
+      sign_in(user)
+    end
+
+    it 'creates a new merge request' do
+      expect { create_merge_request }.to change(project.merge_requests, :count).by(1)
+    end
+
+    it 'render merge request as json' do
+      create_merge_request
+
+      expect(response).to match_response_schema('merge_request')
+    end
+
+    def create_merge_request
+      post :create_merge_request, namespace_id: project.namespace.to_param,
+                                  project_id: project.to_param,
+                                  id: issue.to_param,
+                                  format: :json
+    end
+  end
 end
diff --git a/spec/fixtures/api/schemas/merge_request.json b/spec/fixtures/api/schemas/merge_request.json
new file mode 100644
index 00000000000..36962660cd9
--- /dev/null
+++ b/spec/fixtures/api/schemas/merge_request.json
@@ -0,0 +1,12 @@
+{
+  "type": "object",
+  "required" : [
+    "iid",
+    "url"
+  ],
+  "properties" : {
+    "iid": { "type": "integer" },
+    "url": { "type": "uri" }
+  },
+  "additionalProperties": false
+}