Fix invite sign-in persistence, add invite-only text option, repair account questions

Three registration fixes reported from live use:

- Accepting an invite now keeps the student signed in. The form was
  processed inside render() during the_content, so wp_set_auth_cookie()
  ran after headers were sent and the cookie never persisted — the new
  student was bounced back to the logged-out registration page. The
  submission is now handled on template_redirect (before output) with a
  post/redirect/get, so the cookie sticks and the student lands logged in.

- The "registration is by invitation only" message is now customisable via
  a new block attribute (inviteOnlyMessage / shortcode invite_only_message),
  falling back to the default wording when blank.

- Account-registration questions save again. dbDelta does not reliably
  relax a column from NOT NULL to NULL, so sites created before account-
  scope questions kept us_questions.offering_id NOT NULL and rejected
  account inserts ("Column 'offering_id' cannot be null"). A one-time,
  self-healing migration (guarded by its own option, not the version gate)
  re-applies the nullable definition on next load.

composer test, composer lint, composer cs all pass.

Co-Authored-By: Claude Opus 4.8 <[email protected]>

src/Auth/RegistrationPage.php

@@ -30,6 +30,13 @@ class RegistrationPage {
 	 */
 	private const RESULT_CONFIRM_GROUP = 'confirm_group';
 
+	/**
+	 * Validation error from the most recent submission processed on
+	 * `template_redirect`, carried over to {@see render()} so it can be shown
+	 * inline with the form. Empty when the last submit succeeded or none ran.
+	 */
+	private string $submitError = '';
+
 	public function __construct(
 		private InviteRepository $invites,
 		private PolicyRepository $policies,
@@ -45,15 +52,29 @@ class RegistrationPage {
 	/**
 	 * Renders the student registration shortcode output.
 	 *
-	 * @param array<int|string, mixed> $atts Block attributes (`loginPageId`) or
-	 *                                       shortcode attributes (`login_page_id`).
+	 * @param array<int|string, mixed> $atts Block attributes (`loginPageId`,
+	 *                                       `inviteOnlyMessage`) or shortcode
+	 *                                       attributes (`login_page_id`,
+	 *                                       `invite_only_message`).
 	 */
 	public function render( array $atts ): string {
+		// A just-completed invite signup is redirected back here already logged
+		// in (see maybeHandleSubmit); its success flag distinguishes that from a
+		// visitor who simply happens to be signed in already.
+		// phpcs:ignore WordPress.Security.NonceVerification.Recommended -- read-only display flag; the submit that set it was nonce-checked.
+		$registered = sanitize_key( Val::string( wp_unslash( $_GET['us_registered'] ?? '' ) ) );
+
 		if ( is_user_logged_in() ) {
+			if ( self::RESULT_INVITE === $registered ) {
+				return '<div class="us-register-form"><p class="us-success">'
+					. esc_html__( 'Your account has been created and you are now logged in.', 'unsupervised-schedular' )
+					. '</p></div>';
+			}
+
 			return '<p>' . esc_html__( 'You already have an account and are logged in.', 'unsupervised-schedular' ) . '</p>';
 		}
 
-		// phpcs:ignore WordPress.Security.NonceVerification.Recommended -- token identifies the invite; the form submit is nonce-checked below.
+		// phpcs:ignore WordPress.Security.NonceVerification.Recommended -- token identifies the invite; the form submit is nonce-checked in maybeHandleSubmit.
 		$token = sanitize_text_field( Val::string( wp_unslash( $_REQUEST['us_invite'] ?? '' ) ) );
 		// Only the token's hash is stored, so hash the submitted token for lookup.
 		$invite = '' !== $token ? $this->invites->findByToken( Invite::hashToken( $token ) ) : null;
@@ -65,17 +86,12 @@ class RegistrationPage {
 		// fail to submit — the stale invite's address.
 		$inviteValid = null !== $invite && $invite->isAcceptable( current_time( 'mysql' ) );
 
-		$error       = '';
-		$successType = '';
-
-		if ( isset( $_POST['us_register'] ) && check_admin_referer( 'us_student_register' ) ) {
-			$result = $this->handleSubmit( $invite, $open );
-			if ( in_array( $result, [ self::RESULT_INVITE, self::RESULT_CONFIRM, self::RESULT_CONFIRM_GROUP ], true ) ) {
-				$successType = $result;
-			} else {
-				$error = $result;
-			}
-		}
+		// The submission itself is processed in maybeHandleSubmit on
+		// template_redirect (before any output), so the invite auto-login cookie
+		// is actually sent. Its success signal returns here as ?us_registered;
+		// only a validation error is carried on the instance to show inline.
+		$successType = in_array( $registered, [ self::RESULT_CONFIRM, self::RESULT_CONFIRM_GROUP ], true ) ? $registered : '';
+		$error       = $this->submitError;
 
 		// Result of an email-confirmation link (set by EmailConfirmationHandler's redirect).
 		// phpcs:ignore WordPress.Security.NonceVerification.Recommended -- read-only display flag, not a state change.
@@ -84,9 +100,10 @@ class RegistrationPage {
 		// Where the post-confirmation prompt sends students to sign in.
 		$loginUrl = $this->loginUrl( Val::int( $atts['loginPageId'] ?? $atts['login_page_id'] ?? 0 ) );
 
-		$policyForms      = $this->signupPolicies();
-		$accountQuestions = $this->questions->findByScope( Question::SCOPE_ACCOUNT, activeOnly: true );
-		$canRegister      = $open || $inviteValid;
+		$policyForms       = $this->signupPolicies();
+		$accountQuestions  = $this->questions->findByScope( Question::SCOPE_ACCOUNT, activeOnly: true );
+		$canRegister       = $open || $inviteValid;
+		$inviteOnlyMessage = $this->inviteOnlyMessage( $atts );
 
 		// The two-step script only matters when there is a second step to reveal.
 		if ( $canRegister && '' === $successType && [] !== $accountQuestions ) {
@@ -98,6 +115,77 @@ class RegistrationPage {
 		return (string) ob_get_clean();
 	}
 
+	/**
+	 * Process a submitted registration on `template_redirect`, before any page
+	 * output. Running here (rather than inside {@see render()}, which fires
+	 * during `the_content` after headers are sent) is what lets the invite
+	 * branch's `wp_set_auth_cookie()` actually persist — otherwise the student
+	 * appears logged in for a single render and is logged out on the next view.
+	 *
+	 * On success the request is redirected (post/redirect/get) with a
+	 * `?us_registered` flag so a refresh cannot resubmit; a validation error is
+	 * stashed for {@see render()} to show inline with the form.
+	 */
+	public function maybeHandleSubmit(): void {
+		if ( ! isset( $_POST['us_register'] ) || is_user_logged_in() ) {
+			return;
+		}
+
+		if ( ! check_admin_referer( 'us_student_register' ) ) {
+			return;
+		}
+
+		// phpcs:ignore WordPress.Security.NonceVerification.Missing -- verified by check_admin_referer above.
+		$token  = sanitize_text_field( Val::string( wp_unslash( $_REQUEST['us_invite'] ?? '' ) ) );
+		$invite = '' !== $token ? $this->invites->findByToken( Invite::hashToken( $token ) ) : null;
+		$open   = $this->settings->openRegistrationEnabled();
+
+		$result = $this->handleSubmit( $invite, $open );
+
+		if ( in_array( $result, [ self::RESULT_INVITE, self::RESULT_CONFIRM, self::RESULT_CONFIRM_GROUP ], true ) ) {
+			$this->redirect( add_query_arg( 'us_registered', $result, $this->currentUrl() ) );
+			return;
+		}
+
+		$this->submitError = $result;
+	}
+
+	/**
+	 * The current page's clean permalink, used as the post/redirect/get target
+	 * so the invite token and any stale flags are dropped from the URL.
+	 */
+	private function currentUrl(): string {
+		$url = get_permalink();
+
+		return is_string( $url ) ? $url : home_url( '/' );
+	}
+
+	/**
+	 * Issues the post-submit redirect and stops the request. Split out so tests
+	 * can observe the target without the process exiting.
+	 */
+	protected function redirect( string $url ): void {
+		wp_safe_redirect( $url );
+		exit;
+	}
+
+	/**
+	 * The message shown when registration is closed and no valid invite is
+	 * present. Studios can override the default via the block
+	 * (`inviteOnlyMessage`) or shortcode (`invite_only_message`) attribute.
+	 *
+	 * @param array<int|string, mixed> $atts
+	 */
+	private function inviteOnlyMessage( array $atts ): string {
+		$custom = trim( Val::string( $atts['inviteOnlyMessage'] ?? $atts['invite_only_message'] ?? '' ) );
+
+		if ( '' !== $custom ) {
+			return $custom;
+		}
+
+		return esc_html__( 'Registration is by invitation only. Please use the link from your invitation email, or contact the studio.', 'unsupervised-schedular' );
+	}
+
 	/**
 	 * Redirect to the configured registration page when an invite token lands
 	 * elsewhere (e.g. a link generated before the page was selected). Hooked on

src/BlockRegistrar.php

@@ -105,10 +105,14 @@ class BlockRegistrar {
 			'us-scheduler/student-register' => [
 				'render'     => [ $this, 'renderRegistration' ],
 				'attributes' => [
-					'loginPageId' => [
+					'loginPageId'       => [
 						'type'    => 'number',
 						'default' => 0,
 					],
+					'inviteOnlyMessage' => [
+						'type'    => 'string',
+						'default' => '',
+					],
 				],
 			],
 			'us-scheduler/group-classes'    => [

src/Plugin.php

@@ -51,10 +51,20 @@ class Plugin {
 			( new Installer() )->run();
 		}
 
-		$availability     = new AvailabilityRepository( $wpdb );
-		$bookings         = new BookingRepository( $wpdb );
-		$offerings        = new OfferingRepository( $wpdb );
-		$questions        = new QuestionRepository( $wpdb );
+		$availability = new AvailabilityRepository( $wpdb );
+		$bookings     = new BookingRepository( $wpdb );
+		$offerings    = new OfferingRepository( $wpdb );
+		$questions    = new QuestionRepository( $wpdb );
+
+		// One-time repair for sites where dbDelta left us_questions.offering_id
+		// NOT NULL (it does not reliably relax NULL-ability), which breaks
+		// account-scope registration questions. Guarded by its own flag rather
+		// than the version gate, since affected sites may already be on the
+		// current version. The flag is only set once the ALTER succeeds.
+		if ( '1' !== get_option( 'us_questions_offering_nullable', '' ) && $questions->ensureOfferingNullable() ) {
+			update_option( 'us_questions_offering_nullable', '1' );
+		}
+
 		$answers          = new AnswerRepository( $wpdb );
 		$policies         = new PolicyRepository( $wpdb );
 		$policyVersions   = new PolicyVersionRepository( $wpdb );

src/Registration/QuestionRepository.php

@@ -106,4 +106,26 @@ class QuestionRepository {
 			[ '%d' ]
 		);
 	}
+
+	/**
+	 * Relax `offering_id` to allow NULL for account-scope questions (which are
+	 * not tied to an offering).
+	 *
+	 * The account-questions feature (v1.1.0) made the column nullable in the
+	 * schema, but dbDelta does not reliably change a column from NOT NULL to
+	 * NULL, so sites created before then keep the old NOT NULL column and reject
+	 * account-scope inserts with "Column 'offering_id' cannot be null". This
+	 * MODIFY is idempotent — re-applying the nullable definition is a no-op.
+	 *
+	 * @return bool True when the statement ran (or was already applied), false
+	 *              if it could not be prepared or the query failed.
+	 */
+	public function ensureOfferingNullable(): bool {
+		$sql = $this->db->prepare(
+			'ALTER TABLE %i MODIFY offering_id BIGINT UNSIGNED NULL DEFAULT NULL',
+			$this->table
+		);
+
+		return null !== $sql && false !== $this->db->query( $sql );
+	}
 }

src/ShortcodeRegistrar.php

@@ -23,6 +23,9 @@ class ShortcodeRegistrar {
 		add_shortcode( 'us_student_login', self::shortcode( [ $this->loginPage, 'render' ] ) );
 		add_shortcode( 'us_student_register', self::shortcode( [ $this->registrationPage, 'render' ] ) );
 		add_shortcode( 'us_group_classes', self::shortcode( [ $this->groupClassPage, 'render' ] ) );
+		// Process registration submissions before output so the invite branch's
+		// auth cookie is actually sent (render() runs too late, during the_content).
+		add_action( 'template_redirect', [ $this->registrationPage, 'maybeHandleSubmit' ] );
 		add_action( 'template_redirect', [ $this->registrationPage, 'maybeRedirectToRegistrationPage' ] );
 		add_action( 'wp_enqueue_scripts', [ $this, 'enqueueAssets' ] );
 	}