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[flutter_tools] Forward encoding in ErrorHandlingFile.readAsStringSync - #196136
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Previously, `ErrorHandlingFile.readAsStringSync` dropped its `encoding` parameter when calling `delegate.readAsStringSync()`, forcing UTF-8 decoding even when callers requested another encoding (unlike `readAsString`, `readAsLines`, and `readAsLinesSync`, which already forwarded `encoding`). Because `flutter_tools` wraps `LocalFileSystem` in `ErrorHandlingFileSystem`, callers such as `ScreenshotCommand.ensureOutputIsNotJsonRpcError` crashed with a `FileSystemException` whenever a binary screenshot file under 1000 bytes was read with `AsciiCodec(allowInvalid: true)`. Forward `encoding` to `delegate.readAsStringSync(encoding: encoding)` and add regression tests covering `ErrorHandlingFile.readAsStringSync` backed by `LocalFileSystem` and `ScreenshotCommand.ensureOutputIsNotJsonRpcError` on `ErrorHandlingFileSystem`. Previous output: ``` Screenshot written to flutter_01.skp (0kB). FileSystemException: Failed to decode data using encoding 'utf-8', path = '/tmp/repro_screenshot_skp.QPQNLT/flutter_01.skp' #0 _File._tryDecode (dart:io/file_impl.dart:704:7) #1 _File.readAsStringSync (dart:io/file_impl.dart:715:7) #2 ForwardingFile.readAsStringSync (package:file/src/forwarding/forwarding_file.dart:99:16) #3 ErrorHandlingFile.readAsStringSync.<anonymous closure> (package:flutter_tools/src/base/error_handling_io.dart:258:22) #4 _runSync (package:flutter_tools/src/base/error_handling_io.dart:1116:16) #5 ErrorHandlingFile.readAsStringSync (package:flutter_tools/src/base/error_handling_io.dart:257:12) #6 ScreenshotCommand.ensureOutputIsNotJsonRpcError (package:flutter_tools/src/commands/screenshot.dart:198:39) flutter#7 ScreenshotCommand.runSkia (package:flutter_tools/src/commands/screenshot.dart:180:5) <asynchronous suspension> flutter#8 ScreenshotCommand.runCommand (package:flutter_tools/src/commands/screenshot.dart:123:19) <asynchronous suspension> flutter#9 FlutterCommand.run.<anonymous closure> (package:flutter_tools/src/runner/flutter_command.dart:876:27) <asynchronous suspension> flutter#10 AppContext.run.<anonymous closure> (package:flutter_tools/src/base/context.dart:174:19) <asynchronous suspension> flutter#11 CommandRunner.runCommand (package:args/command_runner.dart:212:13) <asynchronous suspension> flutter#12 FlutterCommandRunner.runCommand.<anonymous closure> (package:flutter_tools/src/runner/flutter_command_runner.dart:689:9) <asynchronous suspension> flutter#13 AppContext.run.<anonymous closure> (package:flutter_tools/src/base/context.dart:174:19) <asynchronous suspension> flutter#14 FlutterCommandRunner.runCommand (package:flutter_tools/src/runner/flutter_command_runner.dart:619:5) <asynchronous suspension> flutter#15 FlutterCommandRunner.run (package:flutter_tools/src/runner/flutter_command_runner.dart:379:5) <asynchronous suspension> flutter#16 run.<anonymous closure>.<anonymous closure>.<anonymous closure>.<anonymous closure> (package:flutter_tools/runner.dart:419:19) <asynchronous suspension> flutter#17 AppContext.run.<anonymous closure> (package:flutter_tools/src/base/context.dart:174:19) <asynchronous suspension> flutter#18 AppContext.run.<anonymous closure> (package:flutter_tools/src/base/context.dart:174:19) <asynchronous suspension> flutter#19 AppContext.run.<anonymous closure> (package:flutter_tools/src/base/context.dart:174:19) <asynchronous suspension> flutter#20 main (package:flutter_tools/executable.dart:133:3) <asynchronous suspension> Feature flags enabled: enable-web, enable-linux-desktop, enable-macos-desktop, enable-windows-desktop, enable-android, enable-ios, cli-animations, enable-native-assets, enable-record-use, enable-swift-package-manager, omit-legacy-version-file, enable-lldb-debugging, enable-uiscene-migration, enable-riscv64, enable-hcpp ``` Current output: ``` Screenshot written to flutter_01.skp (0kB). ```
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This pull request updates ErrorHandlingFile.readAsStringSync to forward the encoding parameter to its delegate, and adds corresponding tests. The review feedback suggests refactoring the unit tests to use MemoryFileSystem instead of LocalFileSystem to avoid physical disk I/O and simplify test setup.
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| testWithoutContext('forwards $encodingName to LocalFileSystem delegate', () { | ||
| final localFileSystem = LocalFileSystem.test(signals: FakeSignals()); | ||
| addTearDown(localFileSystem.dispose); | ||
| final Directory tempDir = localFileSystem.systemTempDirectory.createTempSync( | ||
| 'flutter_tools_read_as_string_sync_test.', | ||
| ); | ||
| addTearDown(() => tryToDelete(tempDir)); | ||
|
|
||
| final fileSystem = ErrorHandlingFileSystem( | ||
| delegate: localFileSystem, | ||
| platform: linuxPlatform, | ||
| ); | ||
| final File file = fileSystem.file(fileSystem.path.join(tempDir.path, 'binary.bin')) | ||
| ..writeAsBytesSync(invalidUtf8Bytes); | ||
|
|
||
| expect(file.readAsStringSync(encoding: encoding), expected); | ||
| }); |
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Using LocalFileSystem in unit tests introduces unnecessary physical disk I/O, which can slow down test execution and lead to flakiness or leftover temporary directories if cleanup fails. Since ErrorHandlingFileSystem is a wrapper that behaves identically regardless of the underlying file system implementation, we can use MemoryFileSystem instead. This simplifies the test setup by removing the need for temporary directory creation, manual cleanup, and teardown registration.
testWithoutContext('forwards $encodingName to MemoryFileSystem delegate', () {
final fileSystem = ErrorHandlingFileSystem(
delegate: MemoryFileSystem.test(),
platform: linuxPlatform,
);
final File file = fileSystem.file('binary.bin')
..writeAsBytesSync(invalidUtf8Bytes);
expect(file.readAsStringSync(encoding: encoding), expected);
});References
- Suggest simplification and refactoring to enhance readability and maintainability, and prefer hermetic tests that avoid unnecessary physical disk I/O. (link)
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flutter/flutter@b98afb5...9c427b5 2026-11-12 [email protected] Roll Skia from d67d0f22e3ec to 9aa2513a4ac9 (2 revisions) (flutter/flutter#196429) 2026-11-12 [email protected] [flutter_tools] Move CpuArch to flutter_tools_core and define HostPlatform by osName and cpuArch (flutter/flutter#195841) 2026-11-12 [email protected] Roll Skia from 23e7e63789b8 to d67d0f22e3ec (2 revisions) (flutter/flutter#196424) 2026-11-12 [email protected] Uber compactify (flutter/flutter#196392) 2026-11-12 [email protected] Roll Skia from 3d7e335da165 to 23e7e63789b8 (12 revisions) (flutter/flutter#196422) 2026-11-12 [email protected] Roll Dart SDK from 13af329ea4f2 to e5add7a25b32 (1 revision) (flutter/flutter#196413) 2026-11-12 [email protected] Don't terminate the shared EGL display when an engine is disposed (flutter/flutter#194520) 2026-11-11 [email protected] Adds manifest flag to turn on SDFs for Android. (flutter/flutter#196056) 2026-11-11 [email protected] Remove bringup from Linux_pixel_7pro integration_ui_keyboard_inset_jump (flutter/flutter#196334) 2026-11-11 [email protected] Uses system default locale for text rendering when preferred locale isn't supported (flutter/flutter#195997) 2026-11-11 [email protected] [android]: prewarms shaders when the context is created (flutter/flutter#196069) 2026-11-11 [email protected] iOS: Recomposite platform views only if their parameters change (flutter/flutter#196287) 2026-11-11 [email protected] [flutter_tools] Forward encoding in ErrorHandlingFile.readAsStringSync (flutter/flutter#196136) 2026-11-11 [email protected] Roll Skia from b89c24bbab8c to 3d7e335da165 (8 revisions) (flutter/flutter#196390) 2026-11-11 [email protected] Add Flutter Gardener instructions on how to disable a test (flutter/flutter#196312) 2026-11-11 [email protected] [Impeller] Enable malioc analysis for framebuffer_blend shaders (flutter/flutter#196343) 2026-11-11 [email protected] [flutter_tools] Migrate general.shard Android, asset, and build tests off globals (flutter/flutter#196125) 2026-11-11 [email protected] Roll Dart SDK from 8f15c4ca2d41 to 13af329ea4f2 (1 revision) (flutter/flutter#196386) 2026-11-11 [email protected] [Impeller] Do not clamp the local coverage limit to the root render target (flutter/flutter#195860) 2026-11-11 [email protected] [Impeller] Use separate uniform buffers on VMware SVGA3D (flutter/flutter#196022) 2026-11-11 [email protected] [flutter_tools] Introduce AndroidSdkProvider for lazy native_assets SDK lookup (flutter/flutter#196122) 2026-11-11 [email protected] Moves linux to ThinLTO. (flutter/flutter#196314) 2026-11-11 [email protected] [flutter_tools] Migrate bin/fuchsia_tester.dart off globals and runInContext (flutter/flutter#196074) 2026-11-11 [email protected] Changes the tolerances for frame_rate_main_test.dart. (flutter/flutter#196304) 2026-11-11 [email protected] Roll Packages from 08faf64 to 653628e (16 revisions) (flutter/flutter#196381) 2026-11-11 [email protected] Allow SliverCrossAxisGroup children to lay out with zero cross-axis extent instead of asserting (flutter/flutter#191287) 2026-11-11 [email protected] Roll Skia from cc4c54f752ba to b89c24bbab8c (4 revisions) (flutter/flutter#196375) 2026-11-11 [email protected] [Linux] Fix layer offset when compositing with glBlitFramebuffer (flutter/flutter#196189) 2026-11-11 [email protected] [flutter_tools] Inject CrashReportSender into SwiftPM migration (flutter/flutter#196315) If this roll has caused a breakage, revert this CL and set the roller to dry run mode using the controls here: https://autoroll.skia.org/r/flutter-packages Please CC [email protected],[email protected] on the revert to ensure that a human is aware of the problem. To file a bug in Packages: https://github.com/flutter/flutter/issues/new/choose To report a problem with the AutoRoller itself, please file a bug: https://issues.skia.org/issues/new?component=1389291&template=1850622 Documentation for the AutoRoller is here: https://skia.googlesource.com/buildbot/+doc/main/autoroll/README.md
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Previously,
ErrorHandlingFile.readAsStringSyncdropped itsencodingparameter when callingdelegate.readAsStringSync(), forcing UTF-8 decoding even when callers requested another encoding (unlikereadAsString,readAsLines, andreadAsLinesSync, which already forwardedencoding). Becauseflutter_toolswrapsLocalFileSysteminErrorHandlingFileSystem, callers such asScreenshotCommand.ensureOutputIsNotJsonRpcError(which passesAsciiCodec(allowInvalid: true)when checking small screenshot files for JSON-RPC error payloads) crashed with aFileSystemException.Forward
encodingtodelegate.readAsStringSync(encoding: encoding)and add regression tests coveringErrorHandlingFile.readAsStringSyncbacked byLocalFileSystemandScreenshotCommand.ensureOutputIsNotJsonRpcErroronErrorHandlingFileSystem.Fixes #196225
Previous output:
Current output: