fix: keep the guest's contact email on the cart and order addresses

src/Drivers/LunarCheckoutDriver.php

@@ -175,6 +175,8 @@ public function complete(CheckoutSession $session, ?string $confirmationToken =
              */
             $order = $cart->completedOrder ?: $cart->draftOrder ?: $cart->createOrder();
 
+            $this->stampContactEmail($session, $cart, $order);
+
             /*
              * How the customer chose to pay, for the panel, mails and any
              * ERP feed (spec 0014 §D). The session records the handle at the
@@ -388,7 +390,7 @@ public function storeShippingAddress(CheckoutSession $session, array $data): Car
         // when the new address still offers it.
         $previousOption = $cart->shippingAddress?->shipping_option;
 
-        $cart->setShippingAddress($this->toCartAddressData($data));
+        $cart->setShippingAddress($this->withContactEmail($session, $cart->shippingAddress, $data));
 
         if ($previousOption !== null) {
             $option = $this->shippingManifest->getOption($cart, $previousOption);
@@ -415,7 +417,7 @@ public function storeBillingAddress(CheckoutSession $session, array $data): Cart
     {
         $cart = $this->operableCart($session);
 
-        $cart->setBillingAddress($this->toCartAddressData($data));
+        $cart->setBillingAddress($this->withContactEmail($session, $cart->billingAddress, $data));
 
         // Spec 0013 §F: a wallet sheet started in collect mode asks for no
         // shipping address, so this billing address is the only one the cart
@@ -425,7 +427,7 @@ public function storeBillingAddress(CheckoutSession $session, array $data): Cart
         // no address and no collect option, and the hold is refused. The
         // address is the customer's own either way.
         if ($cart->shippingAddress === null && PickupPoints::fulfilment($cart) === PickupPoints::COLLECT) {
-            $cart->setShippingAddress($this->toCartAddressData($data));
+            $cart->setShippingAddress($this->withContactEmail($session, null, $data));
             $cart = $this->setFulfilment->execute($cart->refresh(), PickupPoints::COLLECT);
         }
 
@@ -841,6 +843,47 @@ private function assertContactKnown(CheckoutSession $session, Cart $cart): void
         }
     }
 
+    /**
+     * The address payload with the customer's email carried over. Lunar
+     * rewrites the address row wholesale and the address forms never send an
+     * email, so without this the contact step's email is wiped. An email the
+     * payload carries (a wallet sheet's) wins, then the row's own, then the
+     * session's.
+     *
+     * @param  array<string, mixed>  $data
+     * @return array<string, mixed>
+     */
+    private function withContactEmail(CheckoutSession $session, ?CartAddress $existing, array $data): array
+    {
+        $address = $this->toCartAddressData($data);
+        $email = $address['contact_email'] ?? $existing?->contact_email ?? $session->customer_email;
+
+        if (is_string($email) && trim($email) !== '') {
+            $address['contact_email'] = $email;
+        }
+
+        return $address;
+    }
+
+    /**
+     * Give every address on the placed order an email to write to. The cart's
+     * rows can still lack one (contact given after the last address write, or
+     * a signed-in customer known only through the account), and the order is
+     * what confirmations and the panel read.
+     */
+    private function stampContactEmail(CheckoutSession $session, Cart $cart, Order $order): void
+    {
+        $email = $session->customer_email ?? $cart->user?->email;
+
+        if (! is_string($email) || trim($email) === '') {
+            return;
+        }
+
+        $order->addresses()
+            ->where(fn ($query) => $query->whereNull('contact_email')->orWhere('contact_email', ''))
+            ->update(['contact_email' => $email]);
+    }
+
     /**
      * Inverse of {@see toCheckoutAddress()}: the backend-neutral address
      * payload (spec 0010 §B) mapped onto Lunar's CartAddress columns. Absent

tests/Feature/ExpressCollectFlowTest.php

@@ -192,5 +192,7 @@ function collectBasket(): Cart
     expect($session->refresh()->status)->toBeInstanceOf(Completed::class)
         ->and($line->meta['collect'])->toBeTrue()
         ->and($line->meta['pickup_point']['handle'])->toBe('dartford')
-        ->and($order->meta['fulfilment'])->toBe('collect');
+        ->and($order->meta['fulfilment'])->toBe('collect')
+        ->and($order->shippingAddress->contact_email)->toBe('terry@example.com')
+        ->and($order->billingAddress->contact_email)->toBe('terry@example.com');
 });

tests/Feature/GuestContactEmailTest.php

@@ -0,0 +1,87 @@
+<?php
+
+use Illuminate\Foundation\Testing\RefreshDatabase;
+use Lunar\Checkout\Contracts\CheckoutDriver;
+use Lunar\Checkout\Contracts\PaymentMethodRegistry;
+use Lunar\Checkout\PaymentMethods\Offline;
+use Lunar\Core\Models\Order;
+use Lunar\Tests\Checkout\TestCase;
+use Lunar\Tests\Checkout\Utils\CheckoutCart;
+
+uses(TestCase::class, RefreshDatabase::class);
+
+/**
+ * A guest's email lives on the session after the contact step. Lunar rewrites
+ * an address row wholesale and the address forms never send an email, so the
+ * address steps must carry it over, or the placed order has nobody to write to.
+ */
+function guestCheckout(): array
+{
+    $cart = CheckoutCart::orderable();
+    $cart->addresses()->update(['contact_email' => null]);
+    $session = CheckoutCart::session($cart->refresh());
+
+    return [$cart, $session];
+}
+
+function addressPayload(): array
+{
+    return [
+        'first_name' => 'Terry',
+        'last_name' => 'Sparks',
+        'line1' => '1 Trade Counter Way',
+        'city' => 'London',
+        'postcode' => 'SE1 1AA',
+        'country_code' => 'GB',
+    ];
+}
+
+it('keeps the contact email when the shipping address is saved after the contact step', function () {
+    [$cart, $session] = guestCheckout();
+
+    $this->post(route('lunar.checkout.contact.store', $session->uuid), ['email' => 'guest@example.com'])
+        ->assertRedirect();
+    $this->post(route('lunar.checkout.shipping-address.store', $session->uuid), addressPayload())
+        ->assertRedirect();
+
+    expect($cart->refresh()->shippingAddress->contact_email)->toBe('guest@example.com');
+});
+
+it('puts the contact email on the billing address', function () {
+    [$cart, $session] = guestCheckout();
+
+    $this->post(route('lunar.checkout.contact.store', $session->uuid), ['email' => 'guest@example.com']);
+    $this->post(route('lunar.checkout.billing-address.store', $session->uuid), addressPayload());
+
+    expect($cart->refresh()->billingAddress->contact_email)->toBe('guest@example.com');
+});
+
+it('prefers an email the address itself carries, as a wallet sheet sends', function () {
+    [$cart, $session] = guestCheckout();
+
+    $this->post(route('lunar.checkout.contact.store', $session->uuid), ['email' => 'guest@example.com']);
+    app(CheckoutDriver::class)->storeShippingAddress($session->refresh(), [
+        ...addressPayload(),
+        'email' => 'site@example.com',
+    ]);
+
+    expect($cart->refresh()->shippingAddress->contact_email)->toBe('site@example.com');
+});
+
+it('places a guest order whose addresses carry the contact email', function () {
+    app(PaymentMethodRegistry::class)->add(Offline::class);
+    [, $session] = guestCheckout();
+
+    // Only the session knows the email: no address step ran after contact.
+    $this->post(route('lunar.checkout.contact.store', $session->uuid), ['email' => 'guest@example.com']);
+
+    $this->postJson(route('lunar.checkout.pay', $session->uuid), [
+        'fingerprint' => CheckoutCart::fingerprint($session->refresh()),
+        'payment_method' => 'offline',
+    ])->assertSuccessful();
+
+    $order = Order::query()->findOrFail((int) $session->refresh()->order_reference);
+
+    expect($order->shippingAddress->contact_email)->toBe('guest@example.com')
+        ->and($order->billingAddress->contact_email)->toBe('guest@example.com');
+});