FIX: Show better error if no bookmarks found from search (#11284)

See https://meta.discourse.org/t/no-results-for-bookmarks-search-confusing-message/169763

app/controllers/users_controller.rb

@@ -1542,7 +1542,9 @@ class UsersController < ApplicationController
         if bookmark_list.bookmarks.empty?
           render json: {
             bookmarks: [],
-            no_results_help: I18n.t("user_activity.no_bookmarks.self")
+            no_results_help: I18n.t(
+              params[:q].present? ? "user_activity.no_bookmarks.search" : "user_activity.no_bookmarks.self"
+            )
           }
         else
           page = params[:page].to_i + 1

config/locales/server.en.yml

@@ -954,6 +954,7 @@ en:
       others: "No activity."
     no_bookmarks:
       self: "You have no bookmarked posts; bookmarks allow you to quickly refer to specific posts."
+      search: "No bookmarks found with the provided search query."
       others: "No bookmarks."
     no_likes_given:
       self: "You have not liked any posts."

spec/requests/users_controller_spec.rb

@@ -4561,6 +4561,31 @@ describe UsersController do
       get "/u/#{bookmark3.user.username}/bookmarks.json"
       expect(response.status).to eq(403)
     end
+
+    it "shows a helpful message if no bookmarks are found" do
+      bookmark1.destroy
+      bookmark2.destroy
+      bookmark3.destroy
+      sign_in(user)
+      get "/u/#{user.username}/bookmarks.json"
+      expect(response.status).to eq(200)
+      expect(response.parsed_body['bookmarks']).to eq([])
+      expect(response.parsed_body['no_results_help']).to eq(
+        I18n.t('user_activity.no_bookmarks.self')
+      )
+    end
+
+    it "shows a helpful message if no bookmarks are found for the search" do
+      sign_in(user)
+      get "/u/#{user.username}/bookmarks.json", params: {
+        q: 'badsearch'
+      }
+      expect(response.status).to eq(200)
+      expect(response.parsed_body['bookmarks']).to eq([])
+      expect(response.parsed_body['no_results_help']).to eq(
+        I18n.t('user_activity.no_bookmarks.search')
+      )
+    end
   end
 
   def create_second_factor_security_key