FIX: Reset search controller state (#19402)

Fixes an issue on mobile where navigating away from search and returning
results in confusing UI where there are no results but headings says "N
results found".

app/assets/javascripts/discourse/app/controllers/full-page-search.js

@@ -62,6 +62,7 @@ export default Controller.extend({
   page: 1,
   resultCount: null,
   searchTypes: null,
+  selected: [],
 
   init() {
     this._super(...arguments);
@@ -76,7 +77,6 @@ export default Controller.extend({
       },
       { name: I18n.t("search.type.users"), id: SEARCH_TYPE_USERS },
     ]);
-    this.selected = [];
   },
 
   @discourseComputed("resultCount")
@@ -298,6 +298,7 @@ export default Controller.extend({
 
     if (args.page === 1) {
       this.set("bulkSelectEnabled", false);
+
       this.selected.clear();
       this.set("searching", true);
       scrollTop();
@@ -392,6 +393,22 @@ export default Controller.extend({
     }
   },
 
+  _afterTransition() {
+    this._showFooter();
+    if (Object.keys(this.model).length === 0) {
+      this.reset();
+    }
+  },
+
+  reset() {
+    this.setProperties({
+      searching: false,
+      page: 1,
+      resultCount: null,
+      selected: [],
+    });
+  },
+
   @action
   createTopic(searchTerm, event) {
     event?.preventDefault();

app/assets/javascripts/discourse/app/routes/full-page-search.js

@@ -40,7 +40,6 @@ export default DiscourseRoute.extend({
     }
 
     const searchKey = getSearchKey(args);
-
     if (cached && cached.data.searchKey === searchKey) {
       // extend expiry
       setTransient("lastSearch", { searchKey, model: cached.data.model }, 5);
@@ -54,12 +53,7 @@ export default DiscourseRoute.extend({
         return null;
       }
     }).then(async (results) => {
-      const grouped_search_result = results
-        ? results.grouped_search_result
-        : {};
-      const model = (results && (await translateResults(results))) || {
-        grouped_search_result,
-      };
+      const model = (results && (await translateResults(results))) || {};
       setTransient("lastSearch", { searchKey, model }, 5);
       return model;
     });
@@ -67,7 +61,7 @@ export default DiscourseRoute.extend({
 
   @action
   didTransition() {
-    this.controllerFor("full-page-search")._showFooter();
+    this.controllerFor("full-page-search")._afterTransition();
     return true;
   },
 });

spec/system/page_objects/pages/search.rb

@@ -0,0 +1,40 @@
+# frozen_string_literal: true
+
+module PageObjects
+  module Pages
+    class Search < PageObjects::Pages::Base
+
+      def type_in_search(input)
+        find("input.full-page-search").send_keys(input)
+        self
+      end
+
+      def heading_text
+        find("h1.search-page-heading").text
+      end
+
+      def click_search_button
+        find(".search-cta").click
+      end
+
+      def click_home_logo
+        find(".d-header .logo-mobile").click
+      end
+
+      def click_search_icon
+        find(".d-header #search-button").click
+      end
+
+      def has_search_result?
+        within(".search-results") do
+          page.has_selector?(".fps-result", visible: true)
+        end
+      end
+
+      def is_search_page
+        has_css?("body.search-page")
+      end
+
+    end
+  end
+end

spec/system/search_spec.rb

@@ -0,0 +1,41 @@
+# frozen_string_literal: true
+
+describe 'Search', type: :system, js: true do
+  let(:search_page) { PageObjects::Pages::Search.new }
+  fab!(:topic) { Fabricate(:topic) }
+  fab!(:post) { Fabricate(:post, topic: topic, raw: "This is a test post in a test topic") }
+
+  describe "when using full page search on mobile" do
+    before do
+      SearchIndexer.enable
+      SearchIndexer.index(topic, force: true)
+    end
+
+    after do
+      SearchIndexer.disable
+    end
+
+    it "works and clears search page state", mobile: true do
+      visit("/search")
+
+      search_page.type_in_search("test")
+      search_page.click_search_button
+
+      expect(search_page).to have_search_result
+      expect(search_page.heading_text).not_to eq("Search")
+
+      search_page.click_home_logo
+      expect(search_page.is_search_page).to be_falsey
+
+      page.go_back
+      # ensure results are still there when using browser's history
+      expect(search_page).to have_search_result
+
+      search_page.click_home_logo
+      search_page.click_search_icon
+
+      expect(search_page).not_to have_search_result
+      expect(search_page.heading_text).to eq("Search")
+    end
+  end
+end