Keep existing parameters when redirecting dashboard

Keep any existing query parameters, and add the environment parameter.

app/controllers/projects/metrics_dashboard_controller.rb

@@ -18,7 +18,13 @@ module Projects
       if environment
         render 'projects/environments/metrics'
       elsif default_environment
-        redirect_to project_metrics_dashboard_path(project, environment: default_environment)
+        redirect_to project_metrics_dashboard_path(
+          project,
+          **permitted_params
+            .to_h
+            .symbolize_keys
+            .merge(environment: default_environment)
+        )
       else
         render 'projects/environments/empty_metrics'
       end
@@ -26,9 +32,14 @@ module Projects
 
     private
 
+    def permitted_params
+      @permitted_params ||= params.permit(:dashboard_path, :environment, :page)
+    end
+
     def environment
       strong_memoize(:environment) do
-        project.environments.find(params[:environment]) if params[:environment]
+        env = permitted_params[:environment]
+        project.environments.find(env) if env
       end
     end
 

spec/requests/projects/metrics_dashboard_spec.rb

@@ -14,7 +14,7 @@ RSpec.describe 'Projects::MetricsDashboardController' do
   end
 
   describe 'GET /:namespace/:project/-/metrics' do
-    it 'returns 200' do
+    it "redirects to default environment's metrics dashboard" do
       send_request
       expect(response).to redirect_to(dashboard_route(environment: environment))
     end
@@ -24,6 +24,18 @@ RSpec.describe 'Projects::MetricsDashboardController' do
       expect(assigns(:default_environment).id).to eq(environment.id)
     end
 
+    it 'retains existing parameters when redirecting' do
+      get "#{dashboard_route(dashboard_path: '.gitlab/dashboards/dashboard_path.yml')}/panel/new"
+
+      expect(response).to redirect_to(
+        dashboard_route(
+          dashboard_path: '.gitlab/dashboards/dashboard_path.yml',
+          page: 'panel/new',
+          environment: environment
+        )
+      )
+    end
+
     context 'with anonymous user and public dashboard visibility' do
       let(:anonymous_user) { create(:user) }
       let(:project) do