fix(files): do not let a failing move hook break the move or hide files

lib/private/Files/Cache/Updater.php

@@ -123,6 +123,16 @@ public function remove(string $path): void {
 	#[Override]
 	public function renameFromStorage(IStorage $sourceStorage, string $source, string $target): void {
 		$this->copyOrRenameFromStorage($sourceStorage, $source, $target, function (ICache $sourceCache) use ($sourceStorage, $source, $target): void {
+			$parent = dirname($target);
+			if ($parent === '.') {
+				$parent = '';
+			}
+			if (!$this->cache->inCache($parent)) {
+				// scan the parent first, moving the entry below a parent that is not in
+				// the cache would hide it from folder listings until the next scan
+				$this->scanner->scan($parent, Scanner::SCAN_SHALLOW, -1, false);
+			}
+
 			// Remove existing cache entry to no reuse the fileId.
 			if ($this->cache->inCache($target)) {
 				$this->cache->remove($target);
@@ -181,6 +191,12 @@ private function copyOrRenameFromStorage(IStorage $sourceStorage, string $source
 
 			$isDir = $sourceInfo->getMimeType() === FileInfo::MIMETYPE_FOLDER;
 		} else {
+			if (!$this->storage->instanceOfStorage(ObjectStoreStorage::class) && !$this->cache->inCache($target)) {
+				// the source was not in the cache, so the operation could not transfer
+				// an entry to the target. Scan the target to not leave it invisible
+				// until the next scan
+				$this->scanner->scan($target, Scanner::SCAN_SHALLOW, -1, false);
+			}
 			$isDir = $this->storage->is_dir($target);
 		}
 

lib/private/legacy/OC_Hook.php

@@ -85,7 +85,9 @@ public static function emit($signalClass, $signalName, $params = []) {
 		foreach (self::$registered[$signalClass][$signalName] as $i) {
 			try {
 				call_user_func([ $i['class'], $i['name'] ], $params);
-			} catch (Exception $e) {
+			} catch (Throwable $e) {
+				// a failing hook handler must not break the operation that emitted
+				// the signal, this includes Errors like TypeError
 				self::$thrownExceptions[] = $e;
 				Server::get(LoggerInterface::class)->error($e->getMessage(), ['exception' => $e]);
 				if ($e instanceof HintException) {

tests/lib/Files/Cache/UpdaterTest.php

@@ -256,6 +256,48 @@ public function testMoveCrossStorage(): void {
 		$this->assertEquals($cached['fileid'], $cachedTarget['fileid']);
 	}
 
+	public function testMoveCrossStorageMissingTargetParent(): void {
+		$storage2 = new Temporary([]);
+		$cache2 = $storage2->getCache();
+		Filesystem::mount($storage2, [], '/bar');
+		$this->storage->file_put_contents('foo.txt', 'qwerty');
+		$this->updater->update('foo.txt');
+		$cached = $this->cache->get('foo.txt');
+
+		// the target parent exists on disk but is missing from the cache
+		$storage2->mkdir('sub');
+		$this->assertFalse($cache2->inCache('sub'));
+
+		$storage2->moveFromStorage($this->storage, 'foo.txt', 'sub/bar.txt');
+		$storage2->getUpdater()->renameFromStorage($this->storage, 'foo.txt', 'sub/bar.txt');
+
+		$this->assertFalse($this->cache->inCache('foo.txt'));
+		$this->assertTrue($cache2->inCache('sub'));
+		$this->assertTrue($cache2->inCache('sub/bar.txt'));
+
+		// the moved entry is attached to the scanned parent instead of being orphaned
+		$cachedTarget = $cache2->get('sub/bar.txt');
+		$this->assertEquals($cache2->getId('sub'), $cachedTarget['parent']);
+		$this->assertEquals($cached['fileid'], $cachedTarget['fileid']);
+	}
+
+	public function testMoveCrossStorageSourceNotInCache(): void {
+		$storage2 = new Temporary([]);
+		$cache2 = $storage2->getCache();
+		Filesystem::mount($storage2, [], '/bar');
+		$this->storage->file_put_contents('foo.txt', 'qwerty');
+		// the source was never scanned into the cache
+		$this->assertFalse($this->cache->inCache('foo.txt'));
+
+		$storage2->moveFromStorage($this->storage, 'foo.txt', 'bar.txt');
+		$storage2->getUpdater()->renameFromStorage($this->storage, 'foo.txt', 'bar.txt');
+
+		// the target still gets a cache entry
+		$this->assertTrue($cache2->inCache('bar.txt'));
+		$cachedTarget = $cache2->get('bar.txt');
+		$this->assertEquals(6, $cachedTarget['size']);
+	}
+
 	public function testMoveFolderCrossStorage(): void {
 		$storage2 = new Temporary([]);
 		$cache2 = $storage2->getCache();

tests/lib/LegacyHookTest.php

@@ -0,0 +1,52 @@
+<?php
+
+declare(strict_types=1);
+/**
+ * SPDX-FileCopyrightText: 2026 Nextcloud GmbH and Nextcloud contributors
+ * SPDX-License-Identifier: AGPL-3.0-or-later
+ */
+
+namespace Test;
+
+use OCP\HintException;
+
+class LegacyHookTest extends TestCase {
+	#[\Override]
+	protected function setUp(): void {
+		parent::setUp();
+		\OC_Hook::clear('LegacyHookTest');
+	}
+
+	#[\Override]
+	protected function tearDown(): void {
+		\OC_Hook::clear('LegacyHookTest');
+		// the exceptions thrown by the handlers below are expected, do not let
+		// the base test case rethrow them
+		\OC_Hook::$thrownExceptions = [];
+		parent::tearDown();
+	}
+
+	public static function throwTypeError(): void {
+		throw new \TypeError('type error thrown by a hook handler');
+	}
+
+	public static function throwHintException(): void {
+		throw new HintException('hint exception thrown by a hook handler');
+	}
+
+	public function testEmitDoesNotPropagateThrowable(): void {
+		\OC_Hook::connect('LegacyHookTest', 'error', self::class, 'throwTypeError');
+
+		$this->assertTrue(\OC_Hook::emit('LegacyHookTest', 'error'));
+
+		$this->assertCount(1, \OC_Hook::$thrownExceptions);
+		$this->assertInstanceOf(\TypeError::class, \OC_Hook::$thrownExceptions[0]);
+	}
+
+	public function testEmitRethrowsHintException(): void {
+		\OC_Hook::connect('LegacyHookTest', 'hint', self::class, 'throwHintException');
+
+		$this->expectException(HintException::class);
+		\OC_Hook::emit('LegacyHookTest', 'hint');
+	}
+}