Move !is_android to build_engine_artifacts declaration (#54006)
The `//flutter/build/archives:artifacts` target is used to build a zip
archive (artifacts.zip) of host tools such as flutter_tester, the Dart
kernel compiler, the impellerc shader compiler, and other tooling that
is bundled in debug-mode host builds.
This moves the `!is_android` to the definition of
`build_engine_artifacts`. This is required because of the way that we
produce 32-bit arm gen_snapshot for Android on Windows hosts, which
relies on the regular x64 host toolchain due to us having no 32-bit arm
toolchain for Windows. As such, `current_toolchain == host_toolchain` on
that platform.
```
build_engine_artifacts =
flutter_build_engine_artifacts &&
(current_toolchain == host_toolchain ||
(is_linux && !is_chromeos && current_cpu != "arm") || is_mac || is_win)
```
On iOS builds, we don't have this issue since `current_toolchain` will
be one of:
* `//build/toolchain/mac:ios_clang_arm`
* `//build/toolchain/mac:ios_clang_arm_sim`
* `//build/toolchain/mac:ios_clang_x64_sim`
Whereas `host_toolchain` will be one of:
* `//build/toolchain/mac:clang_arm64`
* `//build/toolchain/mac:clang_x64`
This patch also adds documentation to clarify the purpose of this target
and where related artifacts are produced so that future readers don't
need to do a deep dive into our build plumbing to figure this out.
While the target itself is primarily intended for producing host
binaries, one target binary (gen_snapshot) is bundled into the same
archive bundle as the host tools. This should be refactored such that
just like iOS and Android, they are bundled into their own
target-platform-specific archive, and the tool code accordingly updated
to pull these down into the appropriate cache directory.
As a side-note, on macOS we do rely on this archive target for the host
tools, but the bundled gen_snapshot is unused -- instead, one produced
by the //flutter/sky/tools/create_macos_gen_snapshots.py script used.
This should be fixe in a followup patch.
Related: https://github.com/flutter/flutter/issues/38935
Identified while trying to resolve:
Issue: https://github.com/flutter/flutter/issues/101138
Issue: https://github.com/flutter/flutter/issues/69157
## Pre-launch Checklist
- [X] I read the [Contributor Guide] and followed the process outlined
there for submitting PRs.
- [X] I read the [Tree Hygiene] wiki page, which explains my
responsibilities.
- [X] I read and followed the [Flutter Style Guide] and the [C++,
Objective-C, Java style guides].
- [X] I listed at least one issue that this PR fixes in the description
above.
- [X] I added new tests to check the change I am making or feature I am
adding, or the PR is [test-exempt]. See [testing the engine] for
instructions on writing and running engine tests.
- [X] I updated/added relevant documentation (doc comments with `///`).
- [X] I signed the [CLA].
- [X] All existing and new tests are passing.
If you need help, consider asking for advice on the #hackers-new channel
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[Tree Hygiene]: https://github.com/flutter/flutter/wiki/Tree-hygiene
[test-exempt]:
https://github.com/flutter/flutter/wiki/Tree-hygiene#tests
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https://dart.googlesource.com/external/github.com/flutter/engine/+/5810b3fc791f4bb82b9a454014310990eddc1181
Monorepo is:
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
Flutter's instructions for building the engine are at Compiling the engine
They can be followed closely, with a few changes:
goma_ctl ensure_start is sufficient.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 $(command -v gclient))/.cipd_bin goma_ctl ensure_start pushd engine/src flutter/tools/gn --goma --no-prebuilt-dart-sdk --unoptimized --full-dart-sdk autoninja -C out/host_debug_unopt popd
The Flutter commands used to build and run apps will use the locally built Flutter engine and Dart SDK, instead of the one downloaded by the Flutter tool, if the --local-engine option is provided.
For example, to build and run the Flutter spinning square sample on the web platform,
MONOREPO_PATH=$PWD cd flutter/examples/layers flutter --local-engine=host_debug_unopt \ -d chrome run widgets/spinning_square.dart cd $MONOREPO_PATH
To build for desktop, specify the desktop platform device in flutter run as -d macos or -d linux or -d windows. You may also need to run the command
flutter create --platforms=windows,macos,linux
on existing apps, such as sample apps. New apps created with flutter create already include these support files. Details of desktop support are at Desktop Support for Flutter
Tests in the Flutter source tree can be run with the flutter test command, run in the directory of a package containing tests. For example:
MONOREPO_PATH=$PWD cd flutter/packages/flutter flutter test --local-engine=host_debug_unopt cd $MONOREPO_PATH
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.gclient sync needs to be run in an administrator session, because some installed dependencies create symlinks.