Fix setState() silent failure causing state/status desynchronization

When setState() cannot find a matching state in the $possibleStates
array (from STATE_TRANSITION_MATRIX), it now falls back to a direct
lookup in sales_order_status_state for the given status, preferring
the default state mapping. This prevents the order state from being
permanently stuck at its previous value (typically pending_payment)
while the status advances through the order lifecycle.

The fallback query uses addOrder('is_default', 'DESC') to prefer
the default state when a status maps to multiple states, and
setPageSize(1) to limit the SQL query at the database level.

Uses getOrderContext() for consistent logging with the rest of the
module.

Fixes #3288

Author: acourtiol

Helper/Order.php

@@ -493,12 +493,43 @@ private function setState(MagentoOrder $order, $status, $possibleStates): Magent
         }
 
         $this->adyenLogger->addAdyenNotification(
-            'No new state assigned, status should be connected to one of the following states: ' . json_encode($possibleStates),
+            'No new state assigned via preferred states, attempting fallback lookup. '
+            . 'Status should be connected to one of the following states: ' . json_encode($possibleStates),
             [
                 'pspReference' => $order->getPayment()->getData('adyen_psp_reference'),
                 'merchantReference' => $order->getPayment()->getData('entity_id')
             ]);
 
+        // Fallback: resolve state directly from sales_order_status_state without
+        // constraining to $possibleStates. This prevents state/status desynchronization
+        // when the configured status maps to a state not in STATE_TRANSITION_MATRIX.
+        // The fallback is intentionally unconstrained: the status was already set by the
+        // caller, so aligning the state to match is always better than leaving a permanent
+        // mismatch (e.g. state=pending_payment + status=complete).
+        // See https://github.com/Adyen/adyen-magento2/issues/3288
+        $fallbackCollection = $this->orderStatusCollectionFactory->create()
+            ->addFieldToFilter('main_table.status', $status)
+            ->joinStates();
+        $fallbackCollection->getSelect()->order('state_table.is_default DESC');
+        $fallbackCollection->setPageSize(1);
+        $fallbackStatus = $fallbackCollection->getFirstItem();
+        $fallbackState = $fallbackStatus->getState();
+
+        if (!empty($fallbackState)) {
+            $order->setState($fallbackState);
+            $this->adyenLogger->addAdyenNotification(
+                'State set via fallback to ' . $fallbackState
+                . ' (status "' . $status . '" not mapped to preferred states: '
+                . json_encode($possibleStates) . ')',
+                array_merge(
+                    $this->adyenLogger->getOrderContext($order),
+                    ['pspReference' => $order->getPayment()->getData('adyen_psp_reference')]
+                )
+            );
+
+            return $order;
+        }
+
         return $order;
     }