Improve branch-removal logic

Signed-off-by: Dmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>

app/controllers/projects/branches_controller.rb

@@ -4,8 +4,7 @@ class Projects::BranchesController < Projects::ApplicationController
   before_filter :require_non_empty_project
 
   before_filter :authorize_code_access!
-  before_filter :authorize_push!, only: [:create]
-  before_filter :authorize_admin_project!, only: [:destroy]
+  before_filter :authorize_push!, only: [:create, :destroy]
 
   def index
     @branches = Kaminari.paginate_array(@repository.branches).page(params[:page]).per(30)
@@ -22,11 +21,7 @@ class Projects::BranchesController < Projects::ApplicationController
   end
 
   def destroy
-    branch = @repository.find_branch(params[:id])
-
-    if branch && @repository.rm_branch(branch.name)
-      Event.create_ref_event(@project, current_user, branch, 'rm')
-    end
+    DeleteBranchService.new.execute(project, params[:id], current_user)
 
     respond_to do |format|
       format.html { redirect_to project_branches_path(@project) }

app/services/delete_branch_service.rb

@@ -8,6 +8,10 @@ class DeleteBranchService
       return error('No such branch')
     end
 
+    if branch_name == repository.root_ref
+      return error('Cannot remove HEAD branch')
+    end
+
     # Dont allow remove of protected branch
     if project.protected_branch?(branch_name)
       return error('Protected branch cant be removed')

app/views/projects/branches/_branch.html.haml

@@ -16,8 +16,8 @@
           %i.icon-copy
           Compare
 
-      - if can?(current_user, :admin_project, @project) && branch.name != @repository.root_ref
-        = link_to project_branch_path(@project, branch.name), class: 'btn btn-grouped btn-small remove-row', method: :delete, data: { confirm: 'Removed branch cannot be restored. Are you sure?'}, remote: true do
+      - if can_remove_branch?(@project, branch.name)
+        = link_to project_branch_path(@project, branch.name), class: 'btn btn-grouped btn-small btn-remove remove-row', method: :delete, data: { confirm: 'Removed branch cannot be restored. Are you sure?'}, remote: true do
           %i.icon-trash
 
   - if commit