fix: entityExtant()

Signed-off-by: Sebastian Krupinski <krupinski01@gmail.com>

lib/Providers/Service.php

@@ -596,11 +596,17 @@ class Service implements ServiceBaseInterface, ServiceMutableInterface, ServiceC
     {
         $this->initialize();
 
-        $allUids = $this->remoteService->entityList((string) $collection);
-        $uidSet  = array_flip($allUids);  // int[] → [uid => index]
+        // only positive integers are valid UIDs; anything else cannot exist
+        $uids = array_values(array_filter(
+            array_map(static fn (string|int $id): int => (int) $id, $identifiers),
+            static fn (int $uid): bool => $uid > 0,
+        ));
+
+        $existing = array_flip($this->remoteService->entityExtant((string) $collection, ...$uids));
+
         $extant = [];
         foreach ($identifiers as $id) {
-            $extant[$id] = isset($uidSet[(int) $id]);
+            $extant[$id] = isset($existing[(int) $id]) && (string) (int) $id === (string) $id;
         }
         return $extant;
     }

lib/Service/Remote/RemoteMailService.php

@@ -298,6 +298,25 @@ class RemoteMailService
         return $this->entityApplyRange($uids, $range);
     }
 
+    /**
+     * Determine which of the given UIDs exist in a mailbox.
+     *
+     * @return int[]  the subset of the given UIDs that exist
+     */
+    public function entityExtant(string $collection, int ...$uids): array
+    {
+        if ($uids === []) {
+            return [];
+        }
+
+        $this->imapClient()->perform(new SelectCommand($collection, true));
+
+        return $this->imapClient()->perform(new SearchCommand(
+            SearchCriteriaBuilder::create()->uid(SequenceSet::items(...$uids)),
+            IdentifierMode::Uid,
+        ))->matches();
+    }
+
     /**
      * Retrieve a list of messages in a mailbox matching the given filter, sorted and paginated as requested.
      *

tests/php/Unit/ServiceTest.php

@@ -0,0 +1,39 @@
+<?php
+
+declare(strict_types=1);
+
+namespace KTXT\ProviderImap\Tests\Unit;
+
+use KTXM\ProviderImap\Providers\Service;
+use KTXM\ProviderImap\Service\Remote\RemoteMailService;
+use PHPUnit\Framework\TestCase;
+use ReflectionProperty;
+
+final class ServiceTest extends TestCase
+{
+    public function testEntityExtantReportsExistenceOfEachIdentifier(): void
+    {
+        $service = new Service();
+        $remote = new ServiceTestRemoteStub($this->createStub(Service::class));
+        $remote->existing = [5];
+        (new ReflectionProperty(Service::class, 'remoteService'))->setValue($service, $remote);
+
+        $result = $service->entityExtant('INBOX', 5, '6', 'abc', 0);
+
+        $this->assertSame([5 => true, 6 => false, 'abc' => false, 0 => false], $result);
+        $this->assertSame([['INBOX', [5, 6]]], $remote->extantCalls);
+    }
+}
+
+final class ServiceTestRemoteStub extends RemoteMailService
+{
+    /** @var int[] */
+    public array $existing = [];
+    public array $extantCalls = [];
+
+    public function entityExtant(string $collection, int ...$uids): array
+    {
+        $this->extantCalls[] = [$collection, $uids];
+        return array_values(array_intersect($uids, $this->existing));
+    }
+}