Fix form validation with js disabled (#41947)

* Only add the $page query param to form submission url when the form is multipage

* changelog

Committed via a GitHub action: https://github.com/Automattic/jetpack/actions/runs/13535850362

Upstream-Ref: Automattic/jetpack@ba1ee78

Author: talldan

CHANGELOG.md

@@ -5,6 +5,13 @@ All notable changes to this project will be documented in this file.
 The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/)
 and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
+## [0.39.1-alpha] - unreleased
+
+This is an alpha version! The changes listed here are not final.
+
+### Fixed
+- Forms: Fix 404 error when a user submits an invalid form with JavaScript disabled.
+
 ## [0.39.0] - 2025-02-24
 ### Changed
 - Forms: Add Tracks when connecting Google Drive. [#41825]
@@ -857,6 +864,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - Added a new jetpack/forms package [#28409]
 - Added a public load_contact_form method for initializing the contact form module. [#28416]
 
+[0.39.1-alpha]: https://github.com/automattic/jetpack-forms/compare/v0.39.0...v0.39.1-alpha
 [0.39.0]: https://github.com/automattic/jetpack-forms/compare/v0.38.0...v0.39.0
 [0.38.0]: https://github.com/automattic/jetpack-forms/compare/v0.37.1...v0.38.0
 [0.37.1]: https://github.com/automattic/jetpack-forms/compare/v0.37.0...v0.37.1

package.json

@@ -1,7 +1,7 @@
 {
 	"private": true,
 	"name": "@automattic/jetpack-forms",
-	"version": "0.39.0",
+	"version": "0.39.1-alpha",
 	"description": "Jetpack Forms",
 	"homepage": "https://github.com/Automattic/jetpack/tree/HEAD/projects/packages/forms/#readme",
 	"bugs": {

src/class-jetpack-forms.php

@@ -15,7 +15,7 @@
  */
 class Jetpack_Forms {
 
-	const PACKAGE_VERSION = '0.39.0';
+	const PACKAGE_VERSION = '0.39.1-alpha';
 
 	/**
 	 * Load the contact form module.

src/contact-form/class-contact-form.php

@@ -249,7 +249,7 @@ public static function style_on() {
 	 * @return string HTML for the concat form.
 	 */
 	public static function parse( $attributes, $content ) {
-		global $post, $page; // $page is used in the contact-form submission redirect
+		global $post, $page, $multipage; // $page is used in the contact-form submission redirect
 		if ( Settings::is_syncing() ) {
 			return '';
 		}
@@ -346,7 +346,7 @@ public static function parse( $attributes, $content ) {
 			} else {
 				// Submit form to the post permalink
 				$url = get_permalink();
-				if ( $page ) {
+				if ( $multipage && $page ) {
 					$url = add_query_arg( 'page', $page, $url );
 				}
 			}