Address flakes from using temp directory to run tests (#2649)

2172ba7
added support to run tests in a temporary directory.

This results in two flaky issues:

1. On Windows, build_daemon tests may fail to delete the
temp directory because the process may have not been torn
down yet, so it may still be accessing the file system.
There was an initial retry after 1 second, but that appears
to be not enough looking at a recent test run.
2. If a test times out, its tearDown may not be called. In
this case, the ResidentWebRunner in frontend_server may not
restore the current directory in the LocalFileSystem. This
leads to cascading failures in subsequent tests due to no
longer being in a path that contains 'webdev'. See
https://github.com/dart-lang/webdev/actions/runs/15989286213/job/45099373212?pr=2641
for an example. See dart-lang/test#897
as well for tracking work to call tearDown on timeouts.

To address the above issues:

1. Increase the delay between the two tries and assert this
only occurs on Windows.
2. Cache the current directory so that it can be used in
utilities.dart with the same (correct) value every time.

Author: srujzs

dwds/CHANGELOG.md

@@ -1,3 +1,5 @@
+## 24.4.1-wip
+
 ## 24.4.0
 
 - Added support for breakpoint registering on a hot reload with the DDC library bundle format using PausePostRequests.

dwds/lib/src/version.dart

@@ -1,6 +1,6 @@
 name: dwds
 # Every time this changes you need to run `dart run build_runner build`.
-version: 24.4.0
+version: 24.4.1-wip
 
 description: >-
   A service that proxies between the Chrome debug protocol and the Dart VM

dwds/pubspec.yaml

@@ -322,10 +322,12 @@ class TestContext {
             _webRunner = ResidentWebRunner(
               mainUri: entry,
               urlTunneler: debugSettings.urlEncoder,
-              projectDirectory: p.toUri(project.absolutePackageDirectory),
+              projectDirectory: Directory(project.absolutePackageDirectory).uri,
               packageConfigFile: project.packageConfigFile,
               packageUriMapper: packageUriMapper,
-              fileSystemRoots: [p.toUri(project.absolutePackageDirectory)],
+              fileSystemRoots: [
+                Directory(project.absolutePackageDirectory).uri,
+              ],
               fileSystemScheme: 'org-dartlang-app',
               outputPath: outputDir.path,
               compilerOptions: compilerOptions,

dwds/test/fixtures/context.dart

@@ -241,9 +241,18 @@ class TestProject {
       _fixturesCopy.deleteSync(recursive: true);
     } on FileSystemException catch (_) {
       // On Windows, the build daemon process might still be accessing the
-      // working directory, so wait a second and then try again.
-      await Future.delayed(const Duration(seconds: 1));
-      _fixturesCopy.deleteSync(recursive: true);
+      // working directory, so try again with an exponential backoff.
+      var seconds = 1;
+      final maxAttempts = 3;
+      for (var attempt = 0; attempt < maxAttempts; attempt++) {
+        try {
+          _fixturesCopy.deleteSync(recursive: true);
+          break;
+        } on FileSystemException catch (_) {
+          await Future.delayed(Duration(seconds: seconds));
+          seconds *= 2;
+        }
+      }
     }
   }
 

dwds/test/fixtures/project.dart

@@ -26,6 +26,7 @@ class TestAssetServer implements AssetReader {
   // Fallback to "application/octet-stream" on null which
   // makes no claims as to the structure of the data.
   static const String _defaultMimeType = 'application/octet-stream';
+  final Uri _projectDirectory;
   final FileSystem _fileSystem;
   final HttpServer _httpServer;
   final Map<String, Uint8List> _files = {};
@@ -41,6 +42,7 @@ class TestAssetServer implements AssetReader {
     this._httpServer,
     this._packageUriMapper,
     this.internetAddress,
+    this._projectDirectory,
     this._fileSystem,
     this._sdkLayout,
   ) {
@@ -65,6 +67,7 @@ class TestAssetServer implements AssetReader {
   /// trace.
   static Future<TestAssetServer> start(
     String sdkDirectory,
+    Uri projectDirectory,
     FileSystem fileSystem,
     String index,
     String hostname,
@@ -75,8 +78,8 @@ class TestAssetServer implements AssetReader {
     final address = (await InternetAddress.lookup(hostname)).first;
     final httpServer = await HttpServer.bind(address, port);
     final sdkLayout = TestSdkLayout.createDefault(sdkDirectory);
-    final server = TestAssetServer(
-        index, httpServer, packageUriMapper, address, fileSystem, sdkLayout);
+    final server = TestAssetServer(index, httpServer, packageUriMapper, address,
+        projectDirectory, fileSystem, sdkLayout);
     return server;
   }
 
@@ -94,7 +97,7 @@ class TestAssetServer implements AssetReader {
     final headers = <String, String>{};
 
     if (request.url.path.endsWith('.html')) {
-      final indexFile = _fileSystem.file(index);
+      final indexFile = _fileSystem.file(_projectDirectory.resolve(index));
       if (indexFile.existsSync()) {
         headers[HttpHeaders.contentTypeHeader] = 'text/html';
         headers[HttpHeaders.contentLengthHeader] =
@@ -244,8 +247,7 @@ class TestAssetServer implements AssetReader {
     // If this is a dart file, it must be on the local file system and is
     // likely coming from a source map request. The tool doesn't currently
     // consider the case of Dart files as assets.
-    final dartFile =
-        _fileSystem.file(_fileSystem.currentDirectory.uri.resolve(path));
+    final dartFile = _fileSystem.file(_projectDirectory.resolve(path));
     if (dartFile.existsSync()) {
       return dartFile;
     }
@@ -255,7 +257,10 @@ class TestAssetServer implements AssetReader {
     // The file might have been a package file which is signaled by a
     // `/packages/<package>/<path>` request.
     if (segments.first == 'packages') {
-      final resolved = _packageUriMapper.serverPathToResolvedUri(path);
+      var resolved = _packageUriMapper.serverPathToResolvedUri(path);
+      if (resolved != null) {
+        resolved = _projectDirectory.resolveUri(resolved);
+      }
       final packageFile = _fileSystem.file(resolved);
       if (packageFile.existsSync()) {
         return packageFile;
@@ -311,7 +316,7 @@ class TestAssetServer implements AssetReader {
   }
 
   String _parseBasePathFromIndexHtml(String index) {
-    final file = _fileSystem.file(index);
+    final file = _fileSystem.file(_projectDirectory.resolve(index));
     if (!file.existsSync()) {
       throw StateError('Index file $index is not found');
     }

frontend_server_common/lib/src/asset_server.dart

@@ -51,15 +51,11 @@ class WebDevFS {
 
   final TestSdkLayout sdkLayout;
   final CompilerOptions compilerOptions;
-  late final Directory _savedCurrentDirectory;
 
   Future<Uri> create() async {
-    _savedCurrentDirectory = fileSystem.currentDirectory;
-
-    fileSystem.currentDirectory = projectDirectory.toFilePath();
-
     assetServer = await TestAssetServer.start(
       sdkLayout.sdkDirectory,
+      projectDirectory,
       fileSystem,
       index,
       hostname,
@@ -71,7 +67,6 @@ class WebDevFS {
   }
 
   Future<void> dispose() {
-    fileSystem.currentDirectory = _savedCurrentDirectory;
     return assetServer.close();
   }
 
@@ -84,7 +79,8 @@ class WebDevFS {
     required bool fullRestart,
   }) async {
     final mainPath = mainUri.toFilePath();
-    final outputDirectoryPath = fileSystem.file(mainPath).parent.path;
+    final outputDirectory = fileSystem.directory(
+        fileSystem.file(projectDirectory.resolve(mainPath)).parent.path);
     final entryPoint = mainUri.toString();
 
     var prefix = '';
@@ -103,7 +99,10 @@ class WebDevFS {
       final bootstrap = '${prefix}main_module.bootstrap.js';
 
       assetServer.writeFile(
-          entryPoint, fileSystem.file(mainPath).readAsStringSync());
+          entryPoint,
+          fileSystem
+              .file(projectDirectory.resolve(mainPath))
+              .readAsStringSync());
       assetServer.writeFile(stackMapper, stackTraceMapper.readAsStringSync());
 
       switch (ddcModuleFormat) {
@@ -199,14 +198,13 @@ class WebDevFS {
     File metadataFile;
     List<String> modules;
     try {
-      final parentDirectory = fileSystem.directory(outputDirectoryPath);
       codeFile =
-          parentDirectory.childFile('${compilerOutput.outputFilename}.sources');
+          outputDirectory.childFile('${compilerOutput.outputFilename}.sources');
       manifestFile =
-          parentDirectory.childFile('${compilerOutput.outputFilename}.json');
+          outputDirectory.childFile('${compilerOutput.outputFilename}.json');
       sourcemapFile =
-          parentDirectory.childFile('${compilerOutput.outputFilename}.map');
-      metadataFile = parentDirectory
+          outputDirectory.childFile('${compilerOutput.outputFilename}.map');
+      metadataFile = outputDirectory
           .childFile('${compilerOutput.outputFilename}.metadata');
       modules = assetServer.write(
           codeFile, manifestFile, sourcemapFile, metadataFile);

frontend_server_common/lib/src/devfs.dart

@@ -402,7 +402,6 @@ class ResidentCompiler {
       if (compilerOptions.moduleFormat == ModuleFormat.ddc)
         '--dartdevc-module-format=ddc'
     ];
-
     _logger.info(args.join(' '));
     final workingDirectory = projectDirectory.toFilePath();
     _server = await Process.start(sdkLayout.dartAotRuntimePath, args,
@@ -657,7 +656,7 @@ String _toMultiRootPath(
   for (final fileSystemRoot in fileSystemRoots) {
     final rootPath = fileSystemRoot.toFilePath(windows: Platform.isWindows);
     if (filePath.startsWith(rootPath)) {
-      return '$scheme://${filePath.substring(rootPath.length)}';
+      return '$scheme:///${filePath.substring(rootPath.length)}';
     }
   }
   return fileUri.toString();