fix(preview): skip object-store existence checks

ObjectExists() is a network round-trip per preview. Treat the DB row as
authoritative for now so bulk listing stays cheap. Missing objects still
fail later on read. Local storage keeps a real filesystem check.

Assisted-by: Grok:grok-4.6
Signed-off-by: Ray Vincent <rayhvincent@gmail.com>

Author: rayvincent2

lib/private/Preview/Storage/ObjectStorePreviewStorage.php

@@ -176,20 +176,11 @@ public function deleteUnreferencedPreview(Preview $preview): void {
 
 	#[Override]
 	public function previewExists(Preview $preview): bool {
-		if ($preview->getLocationId() === null) {
-			// Without a location the bucket cannot be resolved, which is the case
-			// for rows written before a move to an object store and for the dummy
-			// previews of the unit tests. Never report those as missing, or they
-			// would be dropped on every request.
-			return true;
-		}
-
-		[
-			'urn' => $urn,
-			'store' => $store,
-		] = $this->getObjectStoreInfoForExistingPreview($preview);
-
-		return $store->objectExists($urn);
+		// Avoid a network round-trip per preview. Object-store
+		// existence checks are expensive; treat the DB row as
+		// authoritative for now. Missing objects will still fail
+		// later on read and can be cleaned up by other paths.
+		return true;
 	}
 
 	public function getUrn(Preview $preview, array $config): string {

tests/lib/Preview/Storage/ObjectStorePreviewStorageTest.php

@@ -13,7 +13,6 @@
 use OC\Preview\Db\Preview;
 use OC\Preview\Db\PreviewMapper;
 use OC\Preview\Storage\ObjectStorePreviewStorage;
-use OCP\Files\ObjectStore\IObjectStore;
 use OCP\IConfig;
 use PHPUnit\Framework\MockObject\MockObject;
 use PHPUnit\Framework\TestCase;
@@ -44,42 +43,27 @@ protected function setUp(): void {
 	}
 
 	/**
-	 * Rows without a location cannot resolve a bucket. Treating them as missing
-	 * would drop dummy and pre-migration previews on every request.
+	 * Object-store existence checks are a network round-trip per preview, so
+	 * the DB row is treated as authoritative until a cheaper bulk check exists.
 	 */
-	public function testPreviewExistsWhenLocationIdIsNull(): void {
-		$preview = $this->makePreview(locationId: null);
+	public function testPreviewExistsAlwaysReturnsTrueWithoutQueryingObjectStore(): void {
+		$preview = $this->makePreview(locationId: 'loc-1');
 
 		$this->objectStoreConfig->expects($this->never())->method('getObjectStoreConfiguration');
 		$this->objectStoreConfig->expects($this->never())->method('buildObjectStore');
 
 		$this->assertTrue($this->storage->previewExists($preview));
 	}
 
-	public function testPreviewExistsWhenObjectIsPresent(): void {
-		$preview = $this->makePreview(locationId: 'loc-1');
-		$store = $this->mockObjectStoreForPreview($preview);
+	public function testPreviewExistsWhenLocationIdIsNull(): void {
+		$preview = $this->makePreview(locationId: null);
 
-		$store->expects($this->once())
-			->method('objectExists')
-			->with('urn:oid:preview:' . $preview->getId())
-			->willReturn(true);
+		$this->objectStoreConfig->expects($this->never())->method('getObjectStoreConfiguration');
+		$this->objectStoreConfig->expects($this->never())->method('buildObjectStore');
 
 		$this->assertTrue($this->storage->previewExists($preview));
 	}
 
-	public function testPreviewExistsWhenObjectIsMissing(): void {
-		$preview = $this->makePreview(locationId: 'loc-1');
-		$store = $this->mockObjectStoreForPreview($preview);
-
-		$store->expects($this->once())
-			->method('objectExists')
-			->with('urn:oid:preview:' . $preview->getId())
-			->willReturn(false);
-
-		$this->assertFalse($this->storage->previewExists($preview));
-	}
-
 	private function makePreview(?string $locationId): Preview {
 		$preview = new Preview();
 		$preview->id = 'preview-id-1';
@@ -96,21 +80,4 @@ private function makePreview(?string $locationId): Preview {
 		}
 		return $preview;
 	}
-
-	private function mockObjectStoreForPreview(Preview $preview): IObjectStore&MockObject {
-		$store = $this->createMock(IObjectStore::class);
-		$this->objectStoreConfig->method('getObjectStoreConfiguration')
-			->with($preview->getObjectStoreName())
-			->willReturn([
-				'class' => IObjectStore::class,
-				'arguments' => [
-					'multibucket' => false,
-					'bucket' => 'preview-bucket',
-					'objectPrefix' => 'urn:oid:',
-				],
-			]);
-		$this->objectStoreConfig->method('buildObjectStore')
-			->willReturn($store);
-		return $store;
-	}
 }