[vm] Improve asynchronous unwinding through Stream methods

This CL adds @pragma('vm:awaiter-link') in various places in
Stream implementation to facilitate unwinding and expands
async unwinding logic with more information about
Stream internals.

At the same time be more conservative when checking if an
exception thrown from async method handled: failing to unwind
the stack fully creates situations when we incorrectly report
caught exceptions as uncaught, which frustrates users.

To distinguish stream subscriptions with and without error
handlers we add a state bit. Otherwise, it looks like all
subscriptions have error handlers because if no error
handler is installed we eagerly install error handler forwarding
the error to `Zone.handleUncaughtError`.

Fixes https://github.com/dart-lang/sdk/issues/53334
Fixes https://github.com/dart-lang/sdk/issues/54788
Fixes https://github.com/dart-lang/sdk/issues/47985

TEST=runtime/vm/dart/awaiter_stacks/stream_methods_test.dart,pkg/vm_service/test/pause_on_unhandled_async_exceptions6_test.dart,pkg/vm_service/test/pause_on_unhandled_async_exceptions7_test.dart

CoreLibraryReviewExempt: No behavioral change. Async changes reviewed by lrhn@
Cq-Include-Trybots: luci.dart.try:vm-aot-android-release-arm64c-try,vm-aot-android-release-arm_x64-try,vm-aot-dwarf-linux-product-x64-try,vm-aot-obfuscate-linux-release-x64-try,vm-aot-optimization-level-linux-release-x64-try
Change-Id: Ic51f926867092dd0adbe801b753f57c357c7ace2
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/322720
Reviewed-by: Alexander Markov <alexmarkov@google.com>
Reviewed-by: Lasse Nielsen <lrn@google.com>
Reviewed-by: Ben Konyi <bkonyi@google.com>
Commit-Queue: Slava Egorov <vegorov@google.com>
14 files changed
tree: cadafdb161ec3173e7d1e60bb15c9e60e6ec54fc
  1. .dart_tool/
  2. .github/
  3. benchmarks/
  4. build/
  5. docs/
  6. pkg/
  7. runtime/
  8. samples/
  9. sdk/
  10. tests/
  11. third_party/
  12. tools/
  13. utils/
  14. .clang-format
  15. .gitattributes
  16. .gitconfig
  17. .gitignore
  18. .gn
  19. .mailmap
  20. .style.yapf
  21. AUTHORS
  22. BUILD.gn
  23. CHANGELOG.md
  24. codereview.settings
  25. CONTRIBUTING.md
  26. DEPS
  27. LICENSE
  28. OWNERS
  29. PATENT_GRANT
  30. PRESUBMIT.py
  31. README.dart-sdk
  32. README.md
  33. sdk.code-workspace
  34. sdk_args.gni
  35. SECURITY.md
  36. WATCHLISTS
README.md

Dart

An approachable, portable, and productive language for high-quality apps on any platform

Dart is:

  • Approachable: Develop with a strongly typed programming language that is consistent, concise, and offers modern language features like null safety and patterns.

  • Portable: Compile to ARM, x64, or RISC-V machine code for mobile, desktop, and backend. Compile to JavaScript or WebAssembly for the web.

  • Productive: Make changes iteratively: use hot reload to see the result instantly in your running app. Diagnose app issues using DevTools.

Dart's flexible compiler technology lets you run Dart code in different ways, depending on your target platform and goals:

  • Dart Native: For programs targeting devices (mobile, desktop, server, and more), Dart Native includes both a Dart VM with JIT (just-in-time) compilation and an AOT (ahead-of-time) compiler for producing machine code.

  • Dart Web: For programs targeting the web, Dart Web includes both a development time compiler (dartdevc) and a production time compiler (dart2js).

Dart platforms illustration

License & patents

Dart is free and open source.

See LICENSE and PATENT_GRANT.

Using Dart

Visit dart.dev to learn more about the language, tools, and to find codelabs.

Browse pub.dev for more packages and libraries contributed by the community and the Dart team.

Our API reference documentation is published at api.dart.dev, based on the stable release. (We also publish docs from our beta and dev channels, as well as from the primary development branch).

Building Dart

If you want to build Dart yourself, here is a guide to getting the source, preparing your machine to build the SDK, and building.

There are more documents on our wiki.

Contributing to Dart

The easiest way to contribute to Dart is to file issues.

You can also contribute patches, as described in Contributing.