Handle Project/Package not found more gracefully

Instead of sending people to the 404 page, redirect and render a flash message.

src/api/app/controllers/concerns/webui/rescue_handler.rb

@@ -21,11 +21,12 @@ module Webui::RescueHandler
       end
     end
 
-    rescue_from Package::Errors::ScmsyncReadOnly do |exception|
+    rescue_from Project::Errors::UnknownObjectError, Package::Errors::UnknownObjectError, Package::Errors::ReadSourceAccessError, Package::Errors::ScmsyncReadOnly do |exception|
+      message = exception.message || exception.default_message
       if request.xhr?
-        render json: { error: exception.default_message }, status: exception.status
+        head :not_found
       else
-        flash[:error] = exception.default_message
+        flash[:error] = message
         redirect_back(fallback_location: root_path)
       end
     end

src/api/app/controllers/webui/webui_controller.rb

@@ -45,8 +45,9 @@ def handle_unverified_request
 
   def set_project
     # We've started to use project_name for new routes...
-    @project = ::Project.find_by(name: params[:project_name] || params[:project])
-    raise ActiveRecord::RecordNotFound unless @project
+    project_name = params[:project_name] || params[:project]
+    @project = ::Project.find_by(name: project_name)
+    raise Project::Errors::UnknownObjectError, "Project not found: #{project_name}" unless @project
   end
 
   def require_login

src/api/spec/controllers/webui/webui_controller_spec.rb

@@ -101,10 +101,11 @@ def create
 
   describe 'set_project before filter' do
     context 'with invalid project parameter' do
-      it 'raises an ActiveRecord::RecordNotFound exception' do
-        expect do
-          get :edit, params: { id: 1, project: 'invalid' }
-        end.to raise_error(ActiveRecord::RecordNotFound)
+      it 'redirects back' do
+        from projects_path
+        get :edit, params: { id: 1, project: 'invalid' }
+        expect(flash[:error]).to eq('Project not found: invalid')
+        expect(response).to redirect_to projects_url
       end
     end
 
@@ -122,10 +123,11 @@ def create
     let(:project) { create(:project) }
 
     context 'with invalid package parameter' do
-      it 'raises an Package::Errors::UnknownObjectError exception' do
-        expect do
-          get :create, params: { project: project, package: 'invalid' }
-        end.to raise_error(Package::Errors::UnknownObjectError)
+      it 'redirects back' do
+        from project_show_path(project: project)
+        get :create, params: { project: project, package: 'invalid' }
+        expect(flash[:error]).to eq("Package not found: #{project.name}/invalid")
+        expect(response).to redirect_to project_show_url(project: project)
       end
     end