fix(files_external): propagate child copy failures in AmazonS3::copy()

apps/files_external/lib/Lib/Storage/AmazonS3.php

@@ -558,7 +558,12 @@ public function copy(string $source, string $target, ?bool $isFile = null): bool
 			foreach ($this->getDirectoryContent($source) as $item) {
 				$childSource = $source . '/' . $item['name'];
 				$childTarget = $target . '/' . $item['name'];
-				$this->copy($childSource, $childTarget, $item['mimetype'] !== FileInfo::MIMETYPE_FOLDER);
+				// Propagate copy failure
+				if ($this->copy($childSource, $childTarget, $item['mimetype'] !== FileInfo::MIMETYPE_FOLDER) === false) {
+					// Cache is stale because the target was already partially written
+					$this->invalidateCache($target);
+					return false;
+				}
 			}
 		}
 

apps/files_external/tests/Storage/Amazons3CopyTest.php

@@ -0,0 +1,135 @@
+<?php
+
+declare(strict_types=1);
+/**
+ * SPDX-FileCopyrightText: 2026 Nextcloud GmbH and Nextcloud contributors
+ * SPDX-License-Identifier: AGPL-3.0-only
+ */
+
+namespace OCA\Files_External\Tests\Storage;
+
+use Aws\Command;
+use Aws\S3\Exception\S3Exception;
+use OCA\Files_External\Lib\Storage\AmazonS3;
+use PHPUnit\Framework\MockObject\MockObject;
+use Psr\Log\NullLogger;
+
+class Amazons3CopyTest extends \Test\TestCase {
+	/**
+	 * @param string[] $methods
+	 * @return AmazonS3|MockObject
+	 */
+	private function getStorageMock(array $methods) {
+		$storage = $this->getMockBuilder(AmazonS3::class)
+			->disableOriginalConstructor()
+			->onlyMethods($methods)
+			->getMock();
+
+		// The constructor is disabled, so the properties copy() relies on are uninitialised
+		$this->invokePrivate($storage, 'initCaches');
+		$this->invokePrivate($storage, 'storageClass', ['STANDARD']);
+		// invokePrivate() cannot reach these two: $logger is private, so it is invisible on
+		// the mock subclass, and 'test' resolves to the test() method before the property
+		(new \ReflectionProperty(AmazonS3::class, 'logger'))->setValue($storage, new NullLogger());
+		(new \ReflectionProperty(AmazonS3::class, 'test'))->setValue($storage, false);
+
+		return $storage;
+	}
+
+	private function failingCopyException(): S3Exception {
+		return new S3Exception('NotImplemented', new Command('CopyObject'));
+	}
+
+	/**
+	 * A directory copy must report failure when copying one of its children fails.
+	 */
+	public function testCopyDirectoryReportsFailureWhenChildCopyFails(): void {
+		$storage = $this->getStorageMock(['is_file', 'remove', 'mkdir', 'getDirectoryContent', 'copyObject']);
+
+		$storage->method('is_file')->willReturn(false);
+		$storage->method('remove')->willReturn(true);
+		$storage->method('mkdir')->willReturn(true);
+		$storage->method('getDirectoryContent')->willReturn(new \ArrayIterator([
+			['name' => 'child.txt', 'mimetype' => 'text/plain'],
+		]));
+		$storage->method('copyObject')->willThrowException($this->failingCopyException());
+
+		$this->assertFalse(
+			$storage->copy('source', 'target'),
+			'copy() must report failure when copying a child object fails'
+		);
+	}
+
+	/**
+	 * Renaming a directory must not remove the source when the copy failed.
+	 */
+	public function testRenameDirectoryKeepsSourceWhenCopyFails(): void {
+		$storage = $this->getStorageMock(['is_file', 'remove', 'mkdir', 'getDirectoryContent', 'copyObject', 'rmdir', 'unlink']);
+
+		$storage->method('is_file')->willReturn(false);
+		$storage->method('remove')->willReturn(true);
+		$storage->method('mkdir')->willReturn(true);
+		$storage->method('getDirectoryContent')->willReturn(new \ArrayIterator([
+			['name' => 'child.txt', 'mimetype' => 'text/plain'],
+		]));
+		$storage->method('copyObject')->willThrowException($this->failingCopyException());
+
+		$storage->expects($this->never())->method('rmdir');
+		$storage->expects($this->never())->method('unlink');
+
+		$this->assertFalse(
+			$storage->rename('source', 'target'),
+			'rename() must report failure when the underlying copy failed'
+		);
+	}
+
+	/**
+	 * A failing grandchild must propagate through nested directories as well.
+	 */
+	public function testCopyDirectoryReportsFailureFromNestedDirectory(): void {
+		$storage = $this->getStorageMock(['is_file', 'remove', 'mkdir', 'getDirectoryContent', 'copyObject']);
+
+		$storage->method('is_file')->willReturn(false);
+		$storage->method('remove')->willReturn(true);
+		$storage->method('mkdir')->willReturn(true);
+		$storage->method('getDirectoryContent')->willReturnCallback(
+			function (string $directory): \Traversable {
+				if ($directory === 'source') {
+					return new \ArrayIterator([
+						['name' => 'nested', 'mimetype' => \OC\Files\FileInfo::MIMETYPE_FOLDER],
+					]);
+				}
+				return new \ArrayIterator([
+					['name' => 'child.txt', 'mimetype' => 'text/plain'],
+				]);
+			}
+		);
+		$storage->method('copyObject')->willThrowException($this->failingCopyException());
+
+		$this->assertFalse(
+			$storage->copy('source', 'target'),
+			'copy() must propagate a failure from a nested directory'
+		);
+	}
+
+	/**
+	 * The success path must keep working: a directory whose children all copy fine
+	 * still reports true.
+	 */
+	public function testCopyDirectoryReportsSuccessWhenAllChildrenSucceed(): void {
+		$storage = $this->getStorageMock(['is_file', 'remove', 'mkdir', 'getDirectoryContent', 'copyObject']);
+
+		$storage->method('is_file')->willReturn(false);
+		$storage->method('remove')->willReturn(true);
+		$storage->method('mkdir')->willReturn(true);
+		$storage->method('getDirectoryContent')->willReturn(new \ArrayIterator([
+			['name' => 'child.txt', 'mimetype' => 'text/plain'],
+		]));
+		$storage->method('copyObject')->willReturn(null);
+
+		$this->assertTrue(
+			$storage->copy('source', 'target'),
+			'copy() must still report success when every child copies fine'
+		);
+	}
+}