FIX: Bring back the login-required page for fullpage login (#29316)

app/assets/javascripts/discourse/app/controllers/login.js

@@ -35,6 +35,7 @@ export default class LoginPageController extends Controller {
   @tracked loggingIn = false;
   @tracked loggedIn = false;
   @tracked showLoginButtons = true;
+  @tracked showLogin = false;
   @tracked showSecondFactor = false;
   @tracked loginPassword = "";
   @tracked loginName = "";
@@ -115,6 +116,11 @@ export default class LoginPageController extends Controller {
     return getURL("/u/admin-login");
   }
 
+  @action
+  showLoginPage() {
+    this.showLogin = true;
+  }
+
   @action
   async passkeyLogin(mediation = "optional") {
     try {

app/assets/javascripts/discourse/app/routes/login.js

@@ -21,10 +21,8 @@ export default class LoginRoute extends DiscourseRoute {
   }
 
   model() {
-    if (!this.siteSettings.experimental_full_page_login) {
     return StaticPage.find("login");
   }
-  }
 
   setupController(controller) {
     super.setupController(...arguments);

app/assets/javascripts/discourse/app/templates/login.hbs

@@ -1,4 +1,9 @@
-{{#if this.siteSettings.experimental_full_page_login}}
+{{#if
+  (and
+    this.siteSettings.experimental_full_page_login
+    (or this.showLogin (not this.siteSettings.login_required))
+  )
+}}
   {{hide-application-header-buttons "search" "login" "signup" "menu"}}
   {{hide-application-sidebar}}
 
@@ -163,7 +168,11 @@
           {{/if}}
 
           <DButton
-            @action={{route-action "showLogin"}}
+            @action={{if
+              this.siteSettings.experimental_full_page_login
+              this.showLoginPage
+              (route-action "showLogin")
+            }}
             @icon="user"
             @label="log_in"
             class="btn-primary login-button"

spec/system/login_spec.rb

@@ -115,14 +115,9 @@ shared_examples "login scenarios" do |login_page_object|
 
     it "cannot browse annonymously" do
       visit "/"
-
-      if SiteSetting.experimental_full_page_login
-        expect(page).to have_css(".login-fullpage")
-      else
       expect(page).to have_css(".login-welcome")
       expect(page).to have_css(".site-logo")
       find(".login-welcome .login-button").click
-      end
 
       EmailToken.confirm(Fabricate(:email_token, user: user).token)
       login_form.fill(username: "john", password: "supersecurepassword").click_login