Support branch creation from confidential issue

Accept a `confidential_issue_project_id` param which will
be used for the system note target.

This also includes some refactoring on the spec to use
shared examples.

4 files changed, 170 insertions, 133 deletions

diff --git a/app/controllers/projects/branches_controller.rb b/app/controllers/projects/branches_controller.rb
index fc708400657..df4002d075b 100644
--- a/app/controllers/projects/branches_controller.rb
+++ b/app/controllers/projects/branches_controller.rb
@@ -64,7 +64,7 @@ class Projects::BranchesController < Projects::ApplicationController
     success = (result[:status] == :success)
 
     if params[:issue_iid] && success
-      issue = IssuesFinder.new(current_user, project_id: @project.id).find_by(iid: params[:issue_iid])
+      issue = IssuesFinder.new(current_user, project_id: (confidential_issue_project || @project).id).find_by(iid: params[:issue_iid])
       SystemNoteService.new_issue_branch(issue, @project, current_user, branch_name) if issue
     end
 
@@ -162,4 +162,15 @@ class Projects::BranchesController < Projects::ApplicationController
       @branches = Kaminari.paginate_array(@branches).page(params[:page])
     end
   end
+
+  def confidential_issue_project
+    return unless Feature.enabled?(:create_confidential_merge_request, @project)
+    return if params[:confidential_issue_project_id].blank?
+
+    confidential_issue_project = Project.find(params[:confidential_issue_project_id])
+
+    return unless can?(current_user, :push_code, confidential_issue_project)
+
+    confidential_issue_project
+  end
 end
diff --git a/spec/controllers/projects/branches_controller_spec.rb b/spec/controllers/projects/branches_controller_spec.rb
index cf201c9f735..8c349b1e988 100644
--- a/spec/controllers/projects/branches_controller_spec.rb
+++ b/spec/controllers/projects/branches_controller_spec.rb
@@ -103,6 +103,75 @@ describe Projects::BranchesController do
              }
       end
 
+      context 'confidential_issue_project_id is present' do
+        let(:confidential_issue_project) { create(:project) }
+
+        def create_branch_with_confidential_issue_project
+          post(
+            :create,
+            params: {
+              namespace_id: project.namespace,
+              project_id: project,
+              branch_name: branch,
+              confidential_issue_project_id: confidential_issue_project.id,
+              issue_iid: issue.iid
+            }
+          )
+        end
+
+        context 'create_confidential_merge_request feature is enabled' do
+          before do
+            stub_feature_flags(create_confidential_merge_request: true)
+          end
+
+          context 'user cannot push code to issue project' do
+            let(:issue) { create(:issue, project: confidential_issue_project) }
+
+            it 'does not post a system note' do
+              expect(SystemNoteService).not_to receive(:new_issue_branch)
+
+              create_branch_with_confidential_issue_project
+            end
+          end
+
+          context 'user can push code to issue project' do
+            before do
+              confidential_issue_project.add_developer(user)
+            end
+
+            context 'issue is under the specified project' do
+              let(:issue) { create(:issue, project: confidential_issue_project) }
+
+              it 'posts a system note' do
+                expect(SystemNoteService).to receive(:new_issue_branch).with(issue, confidential_issue_project, user, "1-feature-branch", branch_project: project)
+
+                create_branch_with_confidential_issue_project
+              end
+            end
+
+            context 'issue is not under the specified project' do
+              it 'does not post a system note' do
+                expect(SystemNoteService).not_to receive(:new_issue_branch)
+
+                create_branch_with_confidential_issue_project
+              end
+            end
+          end
+        end
+
+        context 'create_confidential_merge_request feature is disabled' do
+          before do
+            stub_feature_flags(create_confidential_merge_request: false)
+          end
+
+          it 'posts a system note on project' do
+            expect(SystemNoteService).to receive(:new_issue_branch).with(issue, project, user, "1-feature-branch", branch_project: project)
+
+            create_branch_with_confidential_issue_project
+          end
+        end
+      end
+
       context 'repository-less project' do
         let(:project) { create :project }
 
diff --git a/spec/controllers/projects/issues_controller_spec.rb b/spec/controllers/projects/issues_controller_spec.rb
index f82e3c8c7dc..bc5e0b4671e 100644
--- a/spec/controllers/projects/issues_controller_spec.rb
+++ b/spec/controllers/projects/issues_controller_spec.rb
@@ -3,6 +3,8 @@
 require 'spec_helper'
 
 describe Projects::IssuesController do
+  include ProjectForksHelper
+
   let(:project) { create(:project) }
   let(:user)    { create(:user) }
   let(:issue)   { create(:issue, project: project) }
@@ -1130,6 +1132,7 @@ describe Projects::IssuesController do
   end
 
   describe 'POST create_merge_request' do
+    let(:target_project_id) { nil }
     let(:project) { create(:project, :repository, :public) }
 
     before do
@@ -1163,13 +1166,42 @@ describe Projects::IssuesController do
       expect(response).to have_gitlab_http_status(404)
     end
 
+    context 'target_project_id is set' do
+      let(:target_project) { fork_project(project, user, repository: true) }
+      let(:target_project_id) { target_project.id }
+
+      context 'create_confidential_merge_request feature is enabled' do
+        before do
+          stub_feature_flags(create_confidential_merge_request: true)
+        end
+
+        it 'creates a new merge request' do
+          expect { create_merge_request }.to change(target_project.merge_requests, :count).by(1)
+        end
+      end
+
+      context 'create_confidential_merge_request feature is disabled' do
+        before do
+          stub_feature_flags(create_confidential_merge_request: false)
+        end
+
+        it 'creates a new merge request' do
+          expect { create_merge_request }.to change(project.merge_requests, :count).by(1)
+        end
+      end
+    end
+
     def create_merge_request
-      post :create_merge_request, params: {
-                                    namespace_id: project.namespace.to_param,
-                                    project_id: project.to_param,
-                                    id: issue.to_param
-                                  },
-                                  format: :json
+      post(
+        :create_merge_request,
+        params: {
+          namespace_id: project.namespace.to_param,
+          project_id: project.to_param,
+          id: issue.to_param,
+          target_project_id: target_project_id
+        },
+        format: :json
+      )
     end
   end
 
diff --git a/spec/services/merge_requests/create_from_issue_service_spec.rb b/spec/services/merge_requests/create_from_issue_service_spec.rb
index 6b17b14d4b4..2c83b2851a1 100644
--- a/spec/services/merge_requests/create_from_issue_service_spec.rb
+++ b/spec/services/merge_requests/create_from_issue_service_spec.rb
@@ -13,15 +13,20 @@ describe MergeRequests::CreateFromIssueService do
   let(:custom_source_branch) { 'custom-source-branch' }
 
   subject(:service) { described_class.new(project, user, service_params) }
-  subject(:service_with_custom_source_branch) { described_class.new(project, user, service_params.merge(branch_name: custom_source_branch)) }
+  subject(:service_with_custom_source_branch) { described_class.new(project, user, branch_name: custom_source_branch, **service_params) }
 
   before do
     project.add_developer(user)
   end
 
   describe '#execute' do
-    context 'no target_project_id specified' do
-      let(:service_params) { { issue_iid: issue.iid } }
+    shared_examples_for 'a service that creates a merge request from an issue' do
+      it 'returns an error when user can not create merge request on target project' do
+        result = described_class.new(project, create(:user), service_params).execute
+
+        expect(result[:status]).to eq(:error)
+        expect(result[:message]).to eq('Not allowed to create merge request')
+      end
 
       it 'returns an error with invalid issue iid' do
         result = described_class.new(project, user, issue_iid: -1).execute
@@ -30,40 +35,20 @@ describe MergeRequests::CreateFromIssueService do
         expect(result[:message]).to eq('Invalid issue iid')
       end
 
-      it "inherits labels" do
-        issue.assign_attributes(label_ids: label_ids)
-
-        result = service.execute
-
-        expect(result[:merge_request].label_ids).to eq(label_ids)
-      end
-
-      it "inherits milestones" do
-        result = service.execute
-
-        expect(result[:merge_request].milestone_id).to eq(milestone_id)
-      end
-
-      it 'delegates the branch creation to CreateBranchService' do
-        expect_any_instance_of(CreateBranchService).to receive(:execute).once.and_call_original
-
-        service.execute
-      end
-
       it 'creates a branch based on issue title' do
         service.execute
 
-        expect(project.repository.branch_exists?(issue.to_branch_name)).to be_truthy
+        expect(target_project.repository.branch_exists?(issue.to_branch_name)).to be_truthy
       end
 
       it 'creates a branch using passed name' do
         service_with_custom_source_branch.execute
 
-        expect(project.repository.branch_exists?(custom_source_branch)).to be_truthy
+        expect(target_project.repository.branch_exists?(custom_source_branch)).to be_truthy
       end
 
       it 'creates the new_merge_request system note' do
-        expect(SystemNoteService).to receive(:new_merge_request).with(issue, project, user, instance_of(MergeRequest))
+        expect(SystemNoteService).to receive(:new_merge_request).with(issue, target_project, user, instance_of(MergeRequest))
 
         service.execute
       end
@@ -71,19 +56,13 @@ describe MergeRequests::CreateFromIssueService do
       it 'creates the new_issue_branch system note when the branch could be created but the merge_request cannot be created' do
         expect_any_instance_of(MergeRequest).to receive(:valid?).at_least(:once).and_return(false)
 
-        expect(SystemNoteService).to receive(:new_issue_branch).with(issue, project, user, issue.to_branch_name)
+        expect(SystemNoteService).to receive(:new_issue_branch).with(issue, target_project, user, issue.to_branch_name)
 
         service.execute
       end
 
       it 'creates a merge request' do
-        expect { service.execute }.to change(project.merge_requests, :count).by(1)
-      end
-
-      it 'sets the merge request title to: "WIP: Resolves "$issue-title"' do
-        result = service.execute
-
-        expect(result[:merge_request].title).to eq("WIP: Resolve \"#{issue.title}\"")
+        expect { service.execute }.to change(target_project.merge_requests, :count).by(1)
       end
 
       it 'sets the merge request author to current user' do
@@ -107,7 +86,7 @@ describe MergeRequests::CreateFromIssueService do
       it 'sets the merge request target branch to the project default branch' do
         result = service.execute
 
-        expect(result[:merge_request].target_branch).to eq(project.default_branch)
+        expect(result[:merge_request].target_branch).to eq(target_project.default_branch)
       end
 
       it 'executes quick actions if the build service sets them in the description' do
@@ -123,7 +102,7 @@ describe MergeRequests::CreateFromIssueService do
       end
 
       context 'when ref branch is set' do
-        subject { described_class.new(project, user, service_params.merge(ref: 'feature')).execute }
+        subject { described_class.new(project, user, ref: 'feature', **service_params).execute }
 
         it 'sets the merge request source branch to the new issue branch' do
           expect(subject[:merge_request].source_branch).to eq(issue.to_branch_name)
@@ -134,127 +113,73 @@ describe MergeRequests::CreateFromIssueService do
         end
 
         context 'when ref branch does not exist' do
-          subject { described_class.new(project, user, service_params.merge(ref: 'no-such-branch')).execute }
+          subject { described_class.new(project, user, ref: 'no-such-branch', **service_params).execute }
 
           it 'creates a merge request' do
-            expect { subject }.to change(project.merge_requests, :count).by(1)
+            expect { subject }.to change(target_project.merge_requests, :count).by(1)
           end
 
           it 'sets the merge request target branch to the project default branch' do
-            expect(subject[:merge_request].target_branch).to eq(project.default_branch)
+            expect(subject[:merge_request].target_branch).to eq(target_project.default_branch)
           end
         end
       end
     end
 
-    context 'target_project_id is specified' do
-      let(:service_params) { { issue_iid: issue.iid, target_project_id: target_project.id } }
-
-      context 'target project is not a fork of the project' do
-        let(:target_project) { create(:project, :repository) }
-
-        it 'does not create merge request' do
-          expect { service.execute }.to change(target_project.merge_requests, :count).by(0)
-        end
-      end
-
-      context 'target project is a fork of project project' do
-        let(:target_project) { fork_project(project, user, repository: true) }
-
-        it 'creates a branch based on issue title' do
-          service.execute
-
-          expect(target_project.repository.branch_exists?(issue.to_branch_name)).to be_truthy
-        end
-
-        it 'creates a branch using passed name' do
-          service_with_custom_source_branch.execute
-
-          expect(target_project.repository.branch_exists?(custom_source_branch)).to be_truthy
-        end
+    context 'no target_project_id specified' do
+      let(:service_params) { { issue_iid: issue.iid } }
+      let(:target_project) { project }
 
-        it 'creates the new_merge_request system note' do
-          expect(SystemNoteService).to receive(:new_merge_request).with(issue, target_project, user, instance_of(MergeRequest))
+      it_behaves_like 'a service that creates a merge request from an issue'
 
-          service.execute
-        end
+      it "inherits labels" do
+        issue.assign_attributes(label_ids: label_ids)
 
-        it 'creates the new_issue_branch system note when the branch could be created but the merge_request cannot be created' do
-          expect_any_instance_of(MergeRequest).to receive(:valid?).at_least(:once).and_return(false)
+        result = service.execute
 
-          expect(SystemNoteService).to receive(:new_issue_branch).with(issue, target_project, user, issue.to_branch_name)
+        expect(result[:merge_request].label_ids).to eq(label_ids)
+      end
 
-          service.execute
-        end
+      it "inherits milestones" do
+        result = service.execute
 
-        it 'creates a merge request' do
-          expect { service.execute }.to change(target_project.merge_requests, :count).by(1)
-        end
+        expect(result[:merge_request].milestone_id).to eq(milestone_id)
+      end
 
-        it 'sets the merge request title to: "WIP: $issue-branch-name' do
-          result = service.execute
+      it 'sets the merge request title to: "WIP: Resolves "$issue-title"' do
+        result = service.execute
 
-          expect(result[:merge_request].title).to eq("WIP: #{issue.to_branch_name.titleize.humanize}")
-        end
+        expect(result[:merge_request].title).to eq("WIP: Resolve \"#{issue.title}\"")
+      end
+    end
 
-        it 'sets the merge request author to current user' do
-          result = service.execute
+    context 'target_project_id is specified' do
+      let(:service_params) { { issue_iid: issue.iid, target_project_id: target_project.id } }
 
-          expect(result[:merge_request].author).to eq(user)
-        end
+      context 'target project is not a fork of the project' do
+        let(:target_project) { create(:project, :repository) }
 
-        it 'sets the merge request source branch to the new issue branch' do
+        it 'returns an error about not finding the project' do
           result = service.execute
 
-          expect(result[:merge_request].source_branch).to eq(issue.to_branch_name)
+          expect(result[:status]).to eq(:error)
+          expect(result[:message]).to eq('Project not found')
         end
 
-        it 'sets the merge request source branch to the passed branch name' do
-          result = service_with_custom_source_branch.execute
-
-          expect(result[:merge_request].source_branch).to eq(custom_source_branch)
+        it 'does not create merge request' do
+          expect { service.execute }.to change(target_project.merge_requests, :count).by(0)
         end
+      end
 
-        it 'sets the merge request target branch to the project default branch' do
-          result = service.execute
-
-          expect(result[:merge_request].target_branch).to eq(project.default_branch)
-        end
+      context 'target project is a fork of project project' do
+        let(:target_project) { fork_project(project, user, repository: true) }
 
-        it 'executes quick actions if the build service sets them in the description' do
-          allow(service).to receive(:merge_request).and_wrap_original do |m, *args|
-            m.call(*args).tap do |merge_request|
-              merge_request.description = "/assign #{user.to_reference}"
-            end
-          end
+        it_behaves_like 'a service that creates a merge request from an issue'
 
+        it 'sets the merge request title to: "WIP: $issue-branch-name' do
           result = service.execute
 
-          expect(result[:merge_request].assignees).to eq([user])
-        end
-
-        context 'when ref branch is set' do
-          subject { described_class.new(project, user, service_params.merge(ref: 'feature')).execute }
-
-          it 'sets the merge request source branch to the new issue branch' do
-            expect(subject[:merge_request].source_branch).to eq(issue.to_branch_name)
-          end
-
-          it 'sets the merge request target branch to the ref branch' do
-            expect(subject[:merge_request].target_branch).to eq('feature')
-          end
-
-          context 'when ref branch does not exist' do
-            subject { described_class.new(project, user, service_params.merge(ref: 'no-such-branch')).execute }
-
-            it 'creates a merge request' do
-              expect { subject }.to change(target_project.merge_requests, :count).by(1)
-            end
-
-            it 'sets the merge request target branch to the project default branch' do
-              expect(subject[:merge_request].target_branch).to eq(target_project.default_branch)
-            end
-          end
+          expect(result[:merge_request].title).to eq("WIP: #{issue.to_branch_name.titleize.humanize}")
         end
       end
     end