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dart/monorepo//d5d5472f7734c7400d0614f49199f155ab9e9fa6
commit
d5d5472f7734c7400d0614f49199f155ab9e9fa6
[log]
author
Matan Lurey <matanlurey@users.noreply.github.com>
Wed Jun 05 09:53:06 2024 -0700
committer
dart-internal-monorepo <dart-internal-monorepo@dart-ci-internal.iam.gserviceaccount.com>
Wed Jun 05 09:59:20 2024 -0700
tree
681a28e9722d97be357fcc945b50d1d3f2a0f472
parent
c53fa07e6ca7589e0f95327dbd2c1978de7d7e21 [diff]
Re-land #52859: Revamp the engine style guide, remove `always_specify_types` (#53223)

Based on the (internal) discussion around converging on using the official Dart style guide, the design discussion https://flutter.dev/go/use-dart-style-in-flutter-engine, and with the exception of the code that gets published under `dart:ui` (as that is user-facing, and we'd like to evolve the code style in conjunction with the framework), we're going to be (gradually) adopting the Dart style guide in `flutter/engine`.

For now, we:
- Remove `always_specify_types` (except for `lib/ui`, i.e. `dart:ui`)
- Re-enable `type_annotate_public_apis` (which is now relevant since the above is disabled)
- Announce our _intent_ to re-format and apply the Dart formatter (which we'll land in the near future)

---

I also took the opportunity to specify more about our style guide use in general, mostly to make it easier to understand our conventions, and also call out known problem areas (notably, our over-use of `shared_ptr` and `auto` in some cases). I am happy to split those up, but it was easier to make the markdown changes at once.

I also took @cbracken and folks advice and clarified directly that explicit types in Dart are _not_ bad (with examples).
https://dart.googlesource.com/external/github.com/flutter/engine/+/c7667fde2253c483a633b48f5bb4528fc0e82b08
2 files changed
tree: 681a28e9722d97be357fcc945b50d1d3f2a0f472
  1. ci/
  2. tools/
  3. .gitignore
  4. commits.json
  5. DEPS
  6. OWNERS
  7. README.md
README.md

Monorepo

A gclient solution for checking out Dart and Flutter source trees

Monorepo is:

  • Optimized for Tip-of-Tree testing: The Monorepo DEPS used to check out Dart and Flutter dependencies comes from the Flutter engine DEPS with updated dependencies from Dart.

Checking out Monorepo

With depot_tools installed and on your path, create a directory for your monorepo checkout and run these commands to create a gclient solution in that directory:

mkdir monorepo
cd monorepo
gclient config --unmanaged https://dart.googlesource.com/monorepo
gclient sync -D

This gives you a checkout in the monorepo directory that contains:

monorepo/
  DEPS - the DEPS used for this gclient checkout
  commits.json - the pinned commits for Dart, flutter/engine,
                 and flutter/flutter
  tools/ - scripts used to create monorepo DEPS
engine/src/ - the flutter/buildroot repo
    flutter/ - the flutter/engine repo
    out/ - the build directory, where Flutter engine builds are created
    third_party/ - Flutter dependencies checked out by DEPS
      dart/ - the Dart SDK checkout.
        third_party - Dart dependencies, also used by Flutter
flutter/ - the flutter/flutter repo

Building Flutter engine

Flutter's instructions for building the engine are at Compiling the engine

They can be followed closely, with a few changes:

  • Googlers working on Dart do not need to switch to Fuchsia's Goma RBE, except for Windows. The GOMA_DIR enviroment variable can just point to the .cipd_bin directory in a depot_tools installation, and just goma_ctl ensure_start is sufficient.
  • The --no-prebuilt-dart-sdk option has to be added to every gn command, so that the build is set up to build and use a local Dart SDK.
  • The --full-dart-sdk option must be added to gn for the host build target if you will be building web or desktop apps.

Example build commands that work on linux:

MONOREPO_PATH=$PWD
if [[ ! $PATH =~ (^|:)$MONOREPO_PATH/flutter/bin(:|$) ]]; then
  PATH=$MONOREPO_PATH/flutter/bin:$PATH
fi

export GOMA_DIR=$(dirname $(command -v gclient))/.cipd_bin
goma_ctl ensure_start

pushd engine/src
flutter/tools/gn --goma --no-prebuilt-dart-sdk --unoptimized --full-dart-sdk
autoninja -C out/host_debug_unopt
popd

Building Flutter apps

The Flutter commands used to build and run apps will use the locally built Flutter engine and Dart SDK, instead of the one downloaded by the Flutter tool, if the --local-engine option is provided.

For example, to build and run the Flutter spinning square sample on the web platform,

MONOREPO_PATH=$PWD
cd flutter/examples/layers
flutter --local-engine=host_debug_unopt \
  -d chrome run widgets/spinning_square.dart
cd $MONOREPO_PATH

To build for desktop, specify the desktop platform device in flutter run as -d macos or -d linux or -d windows. You may also need to run the command

flutter create --platforms=windows,macos,linux

on existing apps, such as sample apps. New apps created with flutter create already include these support files. Details of desktop support are at Desktop Support for Flutter

Testing

Tests in the Flutter source tree can be run with the flutter test command, run in the directory of a package containing tests. For example:

MONOREPO_PATH=$PWD
cd flutter/packages/flutter
flutter test --local-engine=host_debug_unopt
cd $MONOREPO_PATH

Troubleshooting

Please file an issue or email the dart-engprod team with any problems with or questions about using monorepo.

We will update this documentation to address them.

  • flutter commands may download the engine and Dart SDK files for the configured channel, even though they will be using the local engine and its SDK.

Windows

  • On Windows, gclient sync needs to be run in an administrator session, because some installed dependencies create symlinks.