[3.0] Ensure we set the cookie when presenting the login form

Sources/Actions/Login.php

@@ -71,6 +71,11 @@ public function execute(): void
 			'name' => Lang::getTxt('login', file: 'General'),
 		];
 
+		// Ensure the session data persists.
+		if (empty($_COOKIE)) {
+			Cookie::setLoginCookie(Cookie::LENGTH_DEFAULT, 0, '');
+		}
+
 		// Set the login URL - will be used when the login process is done (but careful not to send us to an attachment).
 		if (isset($_SESSION['old_url']) && !str_contains($_SESSION['old_url'], 'dlattach') && preg_match('~(board|topic)[=,]~', $_SESSION['old_url']) != 0) {
 			$_SESSION['login_url'] = $_SESSION['old_url'];

Sources/Actions/Login2.php

@@ -257,6 +257,7 @@ public function main(): void
 
 		// Cookies are required...
 		if (empty($_COOKIE)) {
+			Cookie::setLoginCookie(Cookie::LENGTH_DEFAULT, 0, '');
 			Utils::$context['login_errors'] = [Lang::getTxt('login_cookie_error', file: 'Errors')];
 
 			return;

Sources/Forum.php

@@ -728,6 +728,10 @@ protected function requireAgreement(): void
 	protected static function inMaintenance(): void
 	{
 		Theme::loadTemplate('Login');
+
+		if (empty($_COOKIE)) {
+			Cookie::setLoginCookie(Cookie::LENGTH_DEFAULT, 0, '');
+		}
 		SecurityToken::create('login');
 
 		// Send a 503 header, so search engines don't bother indexing while we're in maintenance mode.

Sources/User.php

@@ -1578,6 +1578,10 @@ public function kickIfGuest(?string $message = null, bool $log = true): void
 		// Load the Login template and language file.
 		Theme::loadTemplate('Login');
 
+		if (empty($_COOKIE)) {
+			Cookie::setLoginCookie(Cookie::LENGTH_DEFAULT, 0, '');
+		}
+
 		// Create a login token.
 		SecurityToken::create('login');