Support Confirm->Thankyou workflow on contribution pages/events

CRM/Core/Payment/Stripe.php

@@ -340,8 +340,8 @@ class CRM_Core_Payment_Stripe extends CRM_Core_Payment {
     $params = $this->beginDoPayment($params);
 
     // Get the passed in paymentIntent
-    if(!empty(CRM_Utils_Array::value('paymentIntentID', $_POST, NULL))) {
-      $paymentIntentID = CRM_Utils_Array::value('paymentIntentID', $_POST, NULL);
+    if(!empty(CRM_Utils_Array::value('paymentIntentID', $params))) {
+      $paymentIntentID = CRM_Utils_Array::value('paymentIntentID', $params);
     }
     else {
       CRM_Core_Error::statusBounce(E::ts('Unable to complete payment! Missing paymentIntent ID.'));

stripe.php

@@ -171,6 +171,30 @@ function stripe_civicrm_buildForm($formName, &$form) {
   }
 }
 
+/**
+ * Implements hook_civicrm_postProcess().
+ *
+ * @param string $formName
+ * @param \CRM_Core_Form $form
+ */
+function stripe_civicrm_postProcess($formName, &$form) {
+  // We're only interested in forms that have a paymentprocessor
+  if (empty($form->get('paymentProcessor')) || ($form->get('paymentProcessor')['class_name'] !== 'Payment_Stripe')) {
+    return;
+  }
+
+  // Retrieve the paymentIntentID that was posted along with the form and add it to the form params
+  //  This allows multi-page checkout to work (eg. register->confirm->thankyou)
+  $params = $form->get('params');
+  if (isset($params[0])) {
+    $paymentIntentID = CRM_Utils_Request::retrieveValue('paymentIntentID', 'String');
+    if ($paymentIntentID) {
+      $params[0]['paymentIntentID'] = $paymentIntentID;
+      $form->set('params', $params);
+    }
+  }
+}
+
 /**
  * Implements hook_civicrm_check().
  */