Fine. Handle duplicate top-level declarations in manifests.

Introduce first-class support for duplicate or cross-kind top-level name
conflicts in the fine-grained analyzer pipeline.

- Add `declaredConflicts` to `LibraryManifest` to record names that are
  declared more than once (e.g., two classes) or across kinds (e.g., a
  class and a top-level function). Conflicts are assigned a generated
  `ManifestItemId` that is exported and used consistently.
- Ensure conflict handling covers related lookup names (e.g., getter/
  setter pairs `foo` and `foo=`), removing them from per-kind declared
  maps and placing a single entry in `declaredConflicts`.
- Update manifest building to detect conflicts deterministically:
  - Stage variables, then getters/setters, then non-property members.
  - Track `conflictingTopLevelElements` to skip invalid incremental
    updates.
- Include `declaredConflicts` in serialization/deserialization and in
  `exportMap` / `exportedIds`. Make `getDeclaredId` prefer conflicts.
- In `manifest_context`, resolve top-level IDs via `declaredConflicts`
  before per-kind maps for stable identity.
- In requirements computation, skip conflicted names when producing
  instances/interfaces, preventing inconsistent shapes and crashes.
- Make exported extensions resolution null-safe when duplicates exist.
- Extend result printing to display `declaredConflicts`.
- Bump `DATA_VERSION` to 580.

Why: Previously the analyzer assumed unique top-level names, which led
to crashes and inconsistent IDs when a library contained duplicates
(e.g., duplicate extension types, multiple classes named the same, or a
class/function collision). Representing conflicts explicitly yields
stable IDs, predictable exports, and reliable incremental linking and
diagnostics.

Bug: https://github.com/dart-lang/sdk/issues/61741
Change-Id: If153ce467f45156ee3918b5211b8e5e7b7f164ea
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/456485
Reviewed-by: Paul Berry <paulberry@google.com>

https://dart.googlesource.com/sdk/+/cba0ec6ec5aaaff3d8cf6a89a61bbcd3c74d992a
2 files changed
tree: cfc6d156cc7f3bdbd9bcbf31e8d96c66fa671a6d
  1. engine/
  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.