Merge branch '21076-deleted-merged-branches' into 'master'

Add button to delete all merged branches

## What does this MR do?

It adds a button to the branches page that the user can use to delete all the branches that are already merged. This can be used to clean up all the branches that were forgotten to delete while merging MRs.

**Note**  
~~This MR is WIP until MR !6408 is merged.~~

## Are there points in the code the reviewer needs to double check?

The UX of the actual "Delete merged branches" button.

## Why was this MR needed?

Fixes #21076

## Screenshots
![Branches page without "Delete all merged" button](/uploads/3a2936a83c3547a0fce92a74af880a2d/Screen_Shot_2016-10-17_at_20.06.30.png)

Before:
![Screen_Shot_2016-10-17_at_20.07.11](/uploads/55efcebf4e0a45dbfc70ba4a11ca152c/Screen_Shot_2016-10-17_at_20.07.11.png)


After:

## Does this MR meet the acceptance criteria?

- [x] [CHANGELOG](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/CHANGELOG) entry added
- [x] [Documentation created/updated](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/doc/development/doc_styleguide.md)
- [x] API support added
- Tests
  - [x] Added for this feature/bug
  - [x] All builds are passing
- [x] Conform by the [merge request performance guides](http://docs.gitlab.com/ce/development/merge_request_performance_guidelines.html)
- [x] Conform by the [style guides](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/CONTRIBUTING.md#style-guides)
- [x] Branch has no merge conflicts with `master` (if you do - rebase it please)
- [x] [Squashed related commits together](https://git-scm.com/book/en/Git-Tools-Rewriting-History#Squashing-Commits)

## What are the relevant issue numbers?

Closes #21076

See merge request !6449

14 files changed, 231 insertions, 5 deletions

diff --git a/app/assets/stylesheets/framework/buttons.scss b/app/assets/stylesheets/framework/buttons.scss
index e7aff2d0cec..9acff45de75 100644
--- a/app/assets/stylesheets/framework/buttons.scss
+++ b/app/assets/stylesheets/framework/buttons.scss
@@ -141,6 +141,10 @@
     &.btn-save {
       @include btn-outline($white-light, $green-normal, $green-normal, $green-light, $white-light, $green-light);
     }
+
+    &.btn-remove {
+      @include btn-outline($white-light, $red-normal, $red-normal, $red-light, $white-light, $red-light);
+    }
   }
 
   &.btn-gray {
diff --git a/app/controllers/projects/branches_controller.rb b/app/controllers/projects/branches_controller.rb
index 2de8ada3e29..6b9f37983c4 100644
--- a/app/controllers/projects/branches_controller.rb
+++ b/app/controllers/projects/branches_controller.rb
@@ -4,7 +4,7 @@ class Projects::BranchesController < Projects::ApplicationController
   # Authorize
   before_action :require_non_empty_project
   before_action :authorize_download_code!
-  before_action :authorize_push_code!, only: [:new, :create, :destroy]
+  before_action :authorize_push_code!, only: [:new, :create, :destroy, :destroy_all_merged]
 
   def index
     @sort = params[:sort].presence || sort_value_name
@@ -62,6 +62,13 @@ class Projects::BranchesController < Projects::ApplicationController
     end
   end
 
+  def destroy_all_merged
+    DeleteMergedBranchesService.new(@project, current_user).async_execute
+
+    redirect_to namespace_project_branches_path(@project.namespace, @project),
+      notice: 'Merged branches are being deleted. This can take some time depending on the number of branches. Please refresh the page to see changes.'
+  end
+
   private
 
   def ref
diff --git a/app/services/delete_merged_branches_service.rb b/app/services/delete_merged_branches_service.rb
new file mode 100644
index 00000000000..8b8deafedb7
--- /dev/null
+++ b/app/services/delete_merged_branches_service.rb
@@ -0,0 +1,18 @@
+require_relative 'base_service'
+
+class DeleteMergedBranchesService < BaseService
+  def async_execute
+    DeleteMergedBranchesWorker.perform_async(project.id, current_user.id)
+  end
+
+  def execute
+    raise Gitlab::Access::AccessDeniedError unless can?(current_user, :push_code, project)
+
+    branches = project.repository.branch_names
+    branches = branches.select { |branch| project.repository.merged_to_root_ref?(branch) }
+
+    branches.each do |branch|
+      DeleteBranchService.new(project, current_user).execute(branch)
+    end
+  end
+end
diff --git a/app/views/projects/branches/index.html.haml b/app/views/projects/branches/index.html.haml
index 84f38575e84..2246316b540 100644
--- a/app/views/projects/branches/index.html.haml
+++ b/app/views/projects/branches/index.html.haml
@@ -26,6 +26,8 @@
               = sort_title_oldest_updated
 
       - if can? current_user, :push_code, @project
+        = link_to namespace_project_merged_branches_path(@project.namespace, @project), class: 'btn btn-inverted btn-remove has-tooltip', title: "Delete all branches that are merged into '#{@project.repository.root_ref}'", method: :delete, data: { confirm: "Deleting the merged branches cannot be undone. Are you sure?", container: 'body' } do
+          Delete merged branches
         = link_to new_namespace_project_branch_path(@project.namespace, @project), class: 'btn btn-create' do
           New branch
 
diff --git a/app/workers/delete_merged_branches_worker.rb b/app/workers/delete_merged_branches_worker.rb
new file mode 100644
index 00000000000..f870da4ecfd
--- /dev/null
+++ b/app/workers/delete_merged_branches_worker.rb
@@ -0,0 +1,20 @@
+class DeleteMergedBranchesWorker
+  include Sidekiq::Worker
+  include DedicatedSidekiqQueue
+
+  def perform(project_id, user_id)
+    begin
+      project = Project.find(project_id)
+    rescue ActiveRecord::RecordNotFound
+      return
+    end
+
+    user = User.find(user_id)
+
+    begin
+      DeleteMergedBranchesService.new(project, user).execute
+    rescue Gitlab::Access::AccessDeniedError
+      return
+    end
+  end
+end
diff --git a/changelogs/unreleased/21076-deleted-merged-branches.yml b/changelogs/unreleased/21076-deleted-merged-branches.yml
new file mode 100644
index 00000000000..b7fa7f14384
--- /dev/null
+++ b/changelogs/unreleased/21076-deleted-merged-branches.yml
@@ -0,0 +1,4 @@
+---
+title: Add button to delete all merged branches
+merge_request: 6449
+author: Toon Claes
diff --git a/config/routes/project.rb b/config/routes/project.rb
index 82defb0ba71..9cf8465dca8 100644
--- a/config/routes/project.rb
+++ b/config/routes/project.rb
@@ -125,6 +125,7 @@ resources :namespaces, path: '/', constraints: { id: /[a-zA-Z.0-9_\-]+/ }, only:
       end
 
       resources :branches, only: [:index, :new, :create, :destroy], constraints: { id: Gitlab::Regex.git_reference_regex }
+      delete :merged_branches, controller: 'branches', action: :destroy_all_merged
       resources :tags, only: [:index, :show, :new, :create, :destroy], constraints: { id: Gitlab::Regex.git_reference_regex } do
         resource :release, only: [:edit, :update]
       end
diff --git a/config/sidekiq_queues.yml b/config/sidekiq_queues.yml
index 0aec8aedf72..f3531dd30a5 100644
--- a/config/sidekiq_queues.yml
+++ b/config/sidekiq_queues.yml
@@ -34,6 +34,7 @@
   - [project_service, 1]
   - [clear_database_cache, 1]
   - [delete_user, 1]
+  - [delete_merged_branches, 1]
   - [expire_build_instance_artifacts, 1]
   - [group_destroy, 1]
   - [irker, 1]
diff --git a/doc/api/branches.md b/doc/api/branches.md
index 0b5f7778fc7..f68eeb9f86b 100644
--- a/doc/api/branches.md
+++ b/doc/api/branches.md
@@ -240,3 +240,21 @@ Example response:
   "branch_name": "newbranch"
 }
 ```
+
+## Delete merged branches
+
+Will delete all branches that are merged into the project's default branch.
+
+```
+DELETE /projects/:id/repository/merged_branches
+```
+
+| Attribute | Type | Required | Description |
+| --------- | ---- | -------- | ----------- |
+| `id`      | integer | yes | The ID of a project |
+
+It returns `200` to indicate deletion of all merged branches was started.
+
+```bash
+curl --request DELETE --header "PRIVATE-TOKEN: 9koXpg98eAheJpvBs5tK" "https://gitlab.example.com/api/v3/projects/5/repository/merged_branches"
+```
diff --git a/lib/api/branches.rb b/lib/api/branches.rb
index 21a106387f0..73aed624ea7 100644
--- a/lib/api/branches.rb
+++ b/lib/api/branches.rb
@@ -128,6 +128,18 @@ module API
           render_api_error!(result[:message], result[:return_code])
         end
       end
+
+      # Delete all merged branches
+      #
+      # Parameters:
+      #   id (required) - The ID of a project
+      # Example Request:
+      #   DELETE /projects/:id/repository/branches/delete_merged
+      delete ":id/repository/merged_branches" do
+        DeleteMergedBranchesService.new(user_project, current_user).async_execute
+
+        status(200)
+      end
     end
   end
 end
diff --git a/spec/controllers/projects/branches_controller_spec.rb b/spec/controllers/projects/branches_controller_spec.rb
index 644de308c64..f7cf006efd6 100644
--- a/spec/controllers/projects/branches_controller_spec.rb
+++ b/spec/controllers/projects/branches_controller_spec.rb
@@ -1,13 +1,13 @@
 require 'spec_helper'
 
 describe Projects::BranchesController do
-  let(:project) { create(:project) }
-  let(:user)    { create(:user) }
+  let(:project)   { create(:project) }
+  let(:user)      { create(:user) }
+  let(:developer) { create(:user) }
 
   before do
-    sign_in(user)
-
     project.team << [user, :master]
+    project.team << [user, :developer]
 
     allow(project).to receive(:branches).and_return(['master', 'foo/bar/baz'])
     allow(project).to receive(:tags).and_return(['v1.0.0', 'v2.0.0'])
@@ -19,6 +19,8 @@ describe Projects::BranchesController do
 
     context "on creation of a new branch" do
       before do
+        sign_in(user)
+
         post :create,
           namespace_id: project.namespace.to_param,
           project_id: project.to_param,
@@ -68,6 +70,10 @@ describe Projects::BranchesController do
       let(:branch) { "1-feature-branch" }
       let!(:issue) { create(:issue, project: project) }
 
+      before do
+        sign_in(user)
+      end
+
       it 'redirects' do
         post :create,
           namespace_id: project.namespace.to_param,
@@ -94,6 +100,10 @@ describe Projects::BranchesController do
   describe "POST destroy with HTML format" do
     render_views
 
+    before do
+      sign_in(user)
+    end
+
     it 'returns 303' do
       post :destroy,
            format: :html,
@@ -109,6 +119,8 @@ describe Projects::BranchesController do
     render_views
 
     before do
+      sign_in(user)
+
       post :destroy,
            format: :js,
            id: branch,
@@ -139,4 +151,42 @@ describe Projects::BranchesController do
       it { expect(response).to have_http_status(404) }
     end
   end
+
+  describe "DELETE destroy_all_merged" do
+    def destroy_all_merged
+      delete :destroy_all_merged,
+             namespace_id: project.namespace.to_param,
+             project_id: project.to_param
+    end
+
+    context 'when user is allowed to push' do
+      before do
+        sign_in(user)
+      end
+
+      it 'redirects to branches' do
+        destroy_all_merged
+
+        expect(response).to redirect_to namespace_project_branches_path(project.namespace, project)
+      end
+
+      it 'starts worker to delete merged branches' do
+        expect_any_instance_of(DeleteMergedBranchesService).to receive(:async_execute)
+
+        destroy_all_merged
+      end
+    end
+
+    context 'when user is not allowed to push' do
+      before do
+        sign_in(developer)
+      end
+
+      it 'responds with status 404' do
+        destroy_all_merged
+
+        expect(response).to have_http_status(404)
+      end
+    end
+  end
 end
diff --git a/spec/requests/api/branches_spec.rb b/spec/requests/api/branches_spec.rb
index 1711096f4bd..8f605757186 100644
--- a/spec/requests/api/branches_spec.rb
+++ b/spec/requests/api/branches_spec.rb
@@ -299,4 +299,20 @@ describe API::API, api: true  do
       expect(json_response['message']).to eq('Cannot remove HEAD branch')
     end
   end
+
+  describe "DELETE /projects/:id/repository/merged_branches" do
+    before do
+      allow_any_instance_of(Repository).to receive(:rm_branch).and_return(true)
+    end
+
+    it 'returns 200' do
+      delete api("/projects/#{project.id}/repository/merged_branches", user)
+      expect(response).to have_http_status(200)
+    end
+
+    it 'returns a 403 error if guest' do
+      delete api("/projects/#{project.id}/repository/merged_branches", user2)
+      expect(response).to have_http_status(403)
+    end
+  end
 end
diff --git a/spec/services/delete_merged_branches_service_spec.rb b/spec/services/delete_merged_branches_service_spec.rb
new file mode 100644
index 00000000000..181488e89c7
--- /dev/null
+++ b/spec/services/delete_merged_branches_service_spec.rb
@@ -0,0 +1,54 @@
+require 'spec_helper'
+
+describe DeleteMergedBranchesService, services: true do
+  subject(:service) { described_class.new(project, project.owner) }
+
+  let(:project) { create(:project) }
+
+  context '#execute' do
+    context 'unprotected branches' do
+      before do
+        service.execute
+      end
+
+      it 'deletes a branch that was merged' do
+        expect(project.repository.branch_names).not_to include('improve/awesome')
+      end
+
+      it 'keeps branch that is unmerged' do
+        expect(project.repository.branch_names).to include('feature')
+      end
+
+      it 'keeps "master"' do
+        expect(project.repository.branch_names).to include('master')
+      end
+    end
+
+    context 'protected branches' do
+      before do
+        create(:protected_branch, name: 'improve/awesome', project: project)
+        service.execute
+      end
+
+      it 'keeps protected branch' do
+        expect(project.repository.branch_names).to include('improve/awesome')
+      end
+    end
+
+    context 'user without rights' do
+      let(:user) { create(:user) }
+
+      it 'cannot execute' do
+        expect { described_class.new(project, user).execute }.to raise_error(Gitlab::Access::AccessDeniedError)
+      end
+    end
+  end
+
+  context '#async_execute' do
+    it 'calls DeleteMergedBranchesWorker async' do
+      expect(DeleteMergedBranchesWorker).to receive(:perform_async)
+
+      service.async_execute
+    end
+  end
+end
diff --git a/spec/workers/delete_merged_branches_worker_spec.rb b/spec/workers/delete_merged_branches_worker_spec.rb
new file mode 100644
index 00000000000..d9497bd486c
--- /dev/null
+++ b/spec/workers/delete_merged_branches_worker_spec.rb
@@ -0,0 +1,19 @@
+require 'spec_helper'
+
+describe DeleteMergedBranchesWorker do
+  subject(:worker) { described_class.new }
+
+  let(:project) { create(:project) }
+
+  describe "#perform" do
+    it "calls DeleteMergedBranchesService" do
+      expect_any_instance_of(DeleteMergedBranchesService).to receive(:execute).and_return(true)
+
+      worker.perform(project.id, project.owner.id)
+    end
+
+    it "returns false when project was not found" do
+      expect(worker.perform('unknown', project.owner.id)).to be_falsy
+    end
+  end
+end