IBX-8074: Made SiteAccessService react to CONFIG_SCOPE_CHANGE/RESTORE

src/bundle/Core/Resources/config/routing.yml

@@ -93,6 +93,8 @@ services:
             - '@ibexa.config.resolver'
         calls:
             - [setSiteAccess, ['@Ibexa\Core\MVC\Symfony\SiteAccess']]
+        tags:
+            - { name: kernel.event_subscriber }
 
     Ibexa\Core\MVC\Symfony\SiteAccess\SiteAccessServiceInterface:
         alias: 'Ibexa\Core\MVC\Symfony\SiteAccess\SiteAccessService'

src/lib/MVC/Symfony/SiteAccess/SiteAccessService.php

@@ -11,14 +11,18 @@
 use Ibexa\Contracts\Core\SiteAccess\ConfigResolverInterface;
 use Ibexa\Core\Base\Exceptions\InvalidArgumentException;
 use Ibexa\Core\Base\Exceptions\NotFoundException;
+use Ibexa\Core\MVC\Symfony\Event\ScopeChangeEvent;
+use Ibexa\Core\MVC\Symfony\MVCEvents;
 use Ibexa\Core\MVC\Symfony\SiteAccess;
 use function iterator_to_array;
+use Symfony\Component\EventDispatcher\EventSubscriberInterface;
 
-class SiteAccessService implements SiteAccessServiceInterface, SiteAccessAware
+class SiteAccessService implements SiteAccessServiceInterface, SiteAccessAware, EventSubscriberInterface
 {
     private SiteAccessProviderInterface $provider;
 
-    private ?SiteAccess $siteAccess = null;
+    /** @var list<\Ibexa\Core\MVC\Symfony\SiteAccess> */
+    private array $siteAccessStack = [];
 
     private ConfigResolverInterface $configResolver;
 
@@ -30,9 +34,40 @@ public function __construct(
         $this->configResolver = $configResolver;
     }
 
+    public static function getSubscribedEvents(): array
+    {
+        return [
+            MVCEvents::CONFIG_SCOPE_CHANGE => 'onConfigScopeChange',
+            MVCEvents::CONFIG_SCOPE_RESTORE => 'onConfigScopeRestore',
+        ];
+    }
+
     public function setSiteAccess(?SiteAccess $siteAccess = null): void
     {
-        $this->siteAccess = $siteAccess;
+        $this->siteAccessStack = $siteAccess !== null ? [$siteAccess] : [];
+    }
+
+    /**
+     * Pushes the new SiteAccess onto the stack, so that getCurrent() reflects it until the
+     * matching restore happens.
+     */
+    public function onConfigScopeChange(ScopeChangeEvent $event): void
+    {
+        $this->siteAccessStack[] = $event->getSiteAccess();
+    }
+
+    /**
+     * Pops the SiteAccess pushed by the matching onConfigScopeChange(), but never below one
+     * remaining entry: the bottom-most entry (the current request's SiteAccess) must survive an
+     * unbalanced restore.
+     */
+    public function onConfigScopeRestore(ScopeChangeEvent $event): void
+    {
+        if (count($this->siteAccessStack) <= 1) {
+            return;
+        }
+
+        array_pop($this->siteAccessStack);
     }
 
     public function exists(string $name): bool
@@ -56,12 +91,12 @@ public function getAll(): iterable
 
     public function getCurrent(): ?SiteAccess
     {
-        return $this->siteAccess ?? null;
+        return $this->siteAccessStack !== [] ? end($this->siteAccessStack) : null;
     }
 
     public function getSiteAccessesRelation(?SiteAccess $siteAccess = null): array
     {
-        $siteAccess = $siteAccess ?? $this->siteAccess;
+        $siteAccess = $siteAccess ?? $this->getCurrent();
         if ($siteAccess === null) {
             throw new InvalidArgumentException('siteAccess', 'no SiteAccess given and none currently set');
         }

tests/lib/MVC/Symfony/SiteAccess/SiteAccessServiceTest.php

@@ -11,6 +11,8 @@
 use ArrayIterator;
 use Ibexa\Contracts\Core\Repository\Exceptions\NotFoundException;
 use Ibexa\Contracts\Core\SiteAccess\ConfigResolverInterface;
+use Ibexa\Core\MVC\Symfony\Event\ScopeChangeEvent;
+use Ibexa\Core\MVC\Symfony\MVCEvents;
 use Ibexa\Core\MVC\Symfony\SiteAccess;
 use Ibexa\Core\MVC\Symfony\SiteAccess\Provider\StaticSiteAccessProvider;
 use Ibexa\Core\MVC\Symfony\SiteAccess\SiteAccessProviderInterface;
@@ -65,6 +67,91 @@ public function testGetCurrentSiteAccess(): void
         self::assertNull($service->getCurrent());
     }
 
+    public function testGetSubscribedEvents(): void
+    {
+        self::assertSame(
+            [
+                MVCEvents::CONFIG_SCOPE_CHANGE => 'onConfigScopeChange',
+                MVCEvents::CONFIG_SCOPE_RESTORE => 'onConfigScopeRestore',
+            ],
+            SiteAccessService::getSubscribedEvents()
+        );
+    }
+
+    public function testOnConfigScopeChangeMakesGetCurrentReflectTheNewSiteAccess(): void
+    {
+        $service = new SiteAccessService(
+            $this->createStub(SiteAccessProviderInterface::class),
+            $this->createStub(ConfigResolverInterface::class)
+        );
+
+        $baseSiteAccess = new SiteAccess('base');
+        $service->setSiteAccess($baseSiteAccess);
+
+        $previewSiteAccess = new SiteAccess('preview');
+        $service->onConfigScopeChange(new ScopeChangeEvent($previewSiteAccess));
+
+        self::assertSame($previewSiteAccess, $service->getCurrent());
+    }
+
+    public function testOnConfigScopeRestoreBringsBackThePreviousSiteAccess(): void
+    {
+        $service = new SiteAccessService(
+            $this->createStub(SiteAccessProviderInterface::class),
+            $this->createStub(ConfigResolverInterface::class)
+        );
+
+        $baseSiteAccess = new SiteAccess('base');
+        $service->setSiteAccess($baseSiteAccess);
+
+        $previewSiteAccess = new SiteAccess('preview');
+        $service->onConfigScopeChange(new ScopeChangeEvent($previewSiteAccess));
+        $service->onConfigScopeRestore(new ScopeChangeEvent($baseSiteAccess));
+
+        self::assertSame($baseSiteAccess, $service->getCurrent());
+    }
+
+    public function testOnConfigScopeRestoreNeverDropsTheBaseSiteAccess(): void
+    {
+        $service = new SiteAccessService(
+            $this->createStub(SiteAccessProviderInterface::class),
+            $this->createStub(ConfigResolverInterface::class)
+        );
+
+        $baseSiteAccess = new SiteAccess('base');
+        $service->setSiteAccess($baseSiteAccess);
+
+        $service->onConfigScopeRestore(new ScopeChangeEvent($baseSiteAccess));
+
+        self::assertSame($baseSiteAccess, $service->getCurrent());
+    }
+
+    public function testNestedConfigScopeChangesAndRestoresRoundTripLikeAStack(): void
+    {
+        $service = new SiteAccessService(
+            $this->createStub(SiteAccessProviderInterface::class),
+            $this->createStub(ConfigResolverInterface::class)
+        );
+
+        $baseSiteAccess = new SiteAccess('base');
+        $service->setSiteAccess($baseSiteAccess);
+
+        $firstSiteAccess = new SiteAccess('first');
+        $secondSiteAccess = new SiteAccess('second');
+
+        $service->onConfigScopeChange(new ScopeChangeEvent($firstSiteAccess));
+        self::assertSame($firstSiteAccess, $service->getCurrent());
+
+        $service->onConfigScopeChange(new ScopeChangeEvent($secondSiteAccess));
+        self::assertSame($secondSiteAccess, $service->getCurrent());
+
+        $service->onConfigScopeRestore(new ScopeChangeEvent($firstSiteAccess));
+        self::assertSame($firstSiteAccess, $service->getCurrent());
+
+        $service->onConfigScopeRestore(new ScopeChangeEvent($baseSiteAccess));
+        self::assertSame($baseSiteAccess, $service->getCurrent());
+    }
+
     public function testGetSiteAccess(): void
     {
         $staticSiteAccessProvider = new StaticSiteAccessProvider(