Return 404 when deleting non-existant SSH key

Currently when using the UI to delete an SSH key
via the credentials inventory, the HTTP status
code returned is always 201 regardless of the
outcome.

This commits adds a guard clause to render
a 404 Not Found error when attempting to
delete a non-existant SSH key.

ee/app/controllers/concerns/credentials_inventory_actions.rb

@@ -17,16 +17,14 @@ module CredentialsInventoryActions
   def destroy
     key = KeysFinder.new({ users: users, key_type: 'ssh' }).find_by_id(params[:id])
 
-    alert = if key.present?
-              if Keys::DestroyService.new(current_user).execute(key)
+    return render_404 if key.nil?
+
+    alert = if Keys::DestroyService.new(current_user).execute(key)
               notify_deleted_or_revoked_credential(key)
               _('User key was successfully removed.')
             else
               _('Failed to remove user key.')
             end
-            else
-              _('Cannot find user key.')
-            end
 
     redirect_to credentials_inventory_path(filter: 'ssh_keys'), status: :found, notice: alert
   end

ee/changelogs/unreleased/273379-incorrect-status-code-ssh-deletion.yml

+---
+title: Return 404 when attempting to delete non-existent SSH key
+merge_request: 46450
+author:
+type: fixed

ee/spec/support/shared_examples/controllers/credentials_inventory_shared_examples.rb

@@ -63,8 +63,7 @@ RSpec.shared_examples_for 'credentials inventory controller delete SSH key' do |
         it 'renders a not found message' do
           subject
 
-          expect(response).to redirect_to(credentials_path)
-          expect(flash[:notice]).to eql 'Cannot find user key.'
+          expect(response).to have_gitlab_http_status(:not_found)
         end
       end
     end

locale/gitlab.pot

@@ -4853,9 +4853,6 @@ msgstr ""
 msgid "Cannot enable shared runners because parent group does not allow it"
 msgstr ""
 
-msgid "Cannot find user key."
-msgstr ""
-
 msgid "Cannot have multiple Jira imports running at the same time"
 msgstr ""