Gracefully handle adding of no users to projects and groups

- Disable {project, group} members submit button if no users

  If no users are selected, the submit button should be disabled.

- Alert user when no users were added to {project, group}.

  When no users were selected for adding, an alert message is
  flashed that no users were added.

- Also, this commit adds a feedback when users were actually added to a
  project, in symmetry with how group members are handled.

Closes #22967, #23270.

1 files changed, 5 insertions, 1 deletions

diff --git a/app/controllers/projects/project_members_controller.rb b/app/controllers/projects/project_members_controller.rb
index 2a07d154853..2bac48c5490 100644
--- a/app/controllers/projects/project_members_controller.rb
+++ b/app/controllers/projects/project_members_controller.rb
@@ -25,6 +25,10 @@ class Projects::ProjectMembersController < Projects::ApplicationController
   end
 
   def create
+    if params[:user_ids].empty?
+      return redirect_to namespace_project_project_members_path(@project.namespace, @project), alert: 'No users specified.'
+    end
+
     @project.team.add_users(
       params[:user_ids].split(','),
       params[:access_level],
@@ -32,7 +36,7 @@ class Projects::ProjectMembersController < Projects::ApplicationController
       current_user: current_user
     )
 
-    redirect_to namespace_project_project_members_path(@project.namespace, @project)
+    redirect_to namespace_project_project_members_path(@project.namespace, @project), notice: 'Users were successfully added.'
   end
 
   def update