fix: create the destination directory when it is missing (#3223)

packages/localsend_isolates/lib/src/task/server/file_saver.dart

@@ -215,14 +215,14 @@ Future<(String, String?, String)> digestFilePathAndPrepareDirectory({
     if (!p.isWithin(parentDirectory, dir)) {
       throw 'Path traversal detected';
     }
-
-    try {
-      Directory(dir).createSync(recursive: true);
-    } catch (e) {
-      _logger.warning('Could not create directory', e);
-    }
   }
 
+  // The destination directory may not exist anymore, e.g. because it was deleted
+  // or is on a drive that is no longer mounted. This also creates the
+  // sub-directories of a folder transfer. Errors are propagated so that the
+  // caller fails the upload instead of writing to a path that cannot be opened.
+  Directory(dir).createSync(recursive: true);
+
   String destinationPath;
   int counter = 1;
   do {

packages/localsend_isolates/pubspec.lock

@@ -41,6 +41,14 @@ packages:
       url: "https://pub.dev"
     source: hosted
     version: "2.13.1"
+  boolean_selector:
+    dependency: transitive
+    description:
+      name: boolean_selector
+      sha256: "8aab1771e1243a5063b8b0ff68042d67334e3feab9e95b9490f9a6ebf73b42ea"
+      url: "https://pub.dev"
+    source: hosted
+    version: "2.1.2"
   build:
     dependency: transitive
     description:
@@ -113,6 +121,14 @@ packages:
       url: "https://pub.dev"
     source: hosted
     version: "2.0.4"
+  clock:
+    dependency: transitive
+    description:
+      name: clock
+      sha256: fddb70d9b5277016c77a80201021d40a2247104d9f4aa7bab7157b7e3f05b84b
+      url: "https://pub.dev"
+    source: hosted
+    version: "1.1.2"
   collection:
     dependency: "direct main"
     description:
@@ -161,6 +177,14 @@ packages:
       url: "https://pub.dev"
     source: hosted
     version: "3.1.7"
+  fake_async:
+    dependency: transitive
+    description:
+      name: fake_async
+      sha256: "5368f224a74523e8d2e7399ea1638b37aecfca824a3cc4dfdf77bf1fa905ac44"
+      url: "https://pub.dev"
+    source: hosted
+    version: "1.3.3"
   ffi:
     dependency: transitive
     description:
@@ -214,6 +238,11 @@ packages:
       url: "https://pub.dev"
     source: hosted
     version: "2.12.0"
+  flutter_test:
+    dependency: "direct dev"
+    description: flutter
+    source: sdk
+    version: "0.0.0"
   flutter_web_plugins:
     dependency: transitive
     description: flutter
@@ -291,6 +320,30 @@ packages:
       url: "https://pub.dev"
     source: hosted
     version: "4.12.0"
+  leak_tracker:
+    dependency: transitive
+    description:
+      name: leak_tracker
+      sha256: "33e2e26bdd85a0112ec15400c8cbffea70d0f9c3407491f672a2fad47915e2de"
+      url: "https://pub.dev"
+    source: hosted
+    version: "11.0.2"
+  leak_tracker_flutter_testing:
+    dependency: transitive
+    description:
+      name: leak_tracker_flutter_testing
+      sha256: "1dbc140bb5a23c75ea9c4811222756104fbcd1a27173f0c34ca01e16bea473c1"
+      url: "https://pub.dev"
+    source: hosted
+    version: "3.0.10"
+  leak_tracker_testing:
+    dependency: transitive
+    description:
+      name: leak_tracker_testing
+      sha256: "8d5a2d49f4a66b49744b23b018848400d23e54caf9463f4eb20df3eb8acb2eb1"
+      url: "https://pub.dev"
+    source: hosted
+    version: "3.0.2"
   legalize:
     dependency: "direct main"
     description:
@@ -315,6 +368,14 @@ packages:
       url: "https://pub.dev"
     source: hosted
     version: "1.3.0"
+  matcher:
+    dependency: transitive
+    description:
+      name: matcher
+      sha256: dc0b7dc7651697ea4ff3e69ef44b0407ea32c487a39fff6a4004fa585e901861
+      url: "https://pub.dev"
+    source: hosted
+    version: "0.12.19"
   material_color_utilities:
     dependency: transitive
     description:
@@ -575,6 +636,14 @@ packages:
       url: "https://pub.dev"
     source: hosted
     version: "1.2.2"
+  test_api:
+    dependency: transitive
+    description:
+      name: test_api
+      sha256: "949a932224383300f01be9221c39180316445ecb8e7547f70a41a35bf421fb9e"
+      url: "https://pub.dev"
+    source: hosted
+    version: "0.7.11"
   type_plus:
     dependency: transitive
     description:
@@ -614,6 +683,14 @@ packages:
       url: "https://pub.dev"
     source: hosted
     version: "2.2.0"
+  vm_service:
+    dependency: transitive
+    description:
+      name: vm_service
+      sha256: "0016aef94fc66495ac78af5859181e3f3bf2026bd8eecc72b9565601e19ab360"
+      url: "https://pub.dev"
+    source: hosted
+    version: "15.2.0"
   watcher:
     dependency: transitive
     description:

packages/localsend_isolates/pubspec.yaml

@@ -33,4 +33,6 @@ dev_dependencies:
   build_runner: 2.15.1
   dart_mappable_builder: 4.8.0
   flutter_lints: 6.0.0
+  flutter_test:
+    sdk: flutter
   freezed: 3.2.5

packages/localsend_isolates/test/task/server/file_saver_test.dart

@@ -0,0 +1,59 @@
+import 'dart:io';
+
+import 'package:flutter_test/flutter_test.dart';
+import 'package:localsend_isolates/src/task/server/file_saver.dart';
+import 'package:path/path.dart' as p;
+
+void main() {
+  late Directory tempDir;
+
+  setUp(() {
+    tempDir = Directory.systemTemp.createTempSync('file_saver_test');
+  });
+
+  tearDown(() {
+    if (tempDir.existsSync()) {
+      tempDir.deleteSync(recursive: true);
+    }
+  });
+
+  Future<String> digest(String parentDirectory, String fileName) async {
+    final (path, _, _) = await digestFilePathAndPrepareDirectory(
+      parentDirectory: parentDirectory,
+      fileName: fileName,
+      createdDirectories: {},
+    );
+    return path;
+  }
+
+  test('creates the destination directory when it does not exist', () async {
+    final destination = p.join(tempDir.path, 'gone');
+    final path = await digest(destination, 'file.txt');
+
+    expect(Directory(destination).existsSync(), isTrue);
+    expect(path, p.join(destination, 'file.txt'));
+  });
+
+  test('creates the sub-directories of a folder transfer', () async {
+    final path = await digest(tempDir.path, p.join('outer', 'inner', 'file.txt'));
+
+    expect(Directory(p.join(tempDir.path, 'outer', 'inner')).existsSync(), isTrue);
+    expect(path, p.join(tempDir.path, 'outer', 'inner', 'file.txt'));
+  });
+
+  test('keeps an existing directory and its content', () async {
+    File(p.join(tempDir.path, 'file.txt')).writeAsStringSync('hello');
+
+    final path = await digest(tempDir.path, 'file.txt');
+
+    expect(path, p.join(tempDir.path, 'file (2).txt'));
+    expect(File(p.join(tempDir.path, 'file.txt')).readAsStringSync(), 'hello');
+  });
+
+  test('still rejects path traversal', () async {
+    await expectLater(
+      digest(tempDir.path, p.join('..', 'escaped', 'file.txt')),
+      throwsA('Path traversal detected'),
+    );
+  });
+}