Rolling Mojo

This page describes the process for rolling new versions of Mojo into Flutter.

• Update your Flutter checkout to tip-of-tree.
• In your Flutter checkout, create a branch to work with: git checkout upstream/master -tb roll_mojo
• Clean your Flutter checkout (e.g., git clean -fd) such that git status reports working directory clean
• Update your Mojo checkout to the revision you wish to roll into Flutter.
• Clean your Mojo checkout (e.g., git clean -fd) such that git status reports working directory clean.
• /path/to/flutter/engine/src/sky/tools/roll/roll.py --dest-dir=/path/to/flutter/engine/src --mojo-dir=/path/to/mojo/src
• Update the mojo_sdk_revision in the DEPS based on the git hashes in the mojo_sdk.git repository.
• Update the mojo_sdk version number in //sky/packages/sky_services/pubspec.yaml to the latest version from https://pub.dartlang.org/packages/mojo_sdk. Note: This version needs to be binary compatible with the mojo_sdk_revision revision in the previous step, which might require publishing a new version of the mojo_sdk Dart package if the currently published package.
• Locally commit the change to DEPS and pubspec.yaml.
• Run gclient sync to ensure that the dependencies are up to date.
• The roll.py script will create a few commits in your branch that update the Mojo revision. We now need to validate that we didn't break anything:
  • sky/tools/gn --runtime-mode=debug --unoptimized
  • ninja -C out/host_debug_unopt
  • In your flutter.git checkout: flutter test --debug --flutter-repo
  • sky/tools/gn --android --runtime-mode=debug --unoptimized
  • ninja -C out/android_debug_unopt
• Once you are satisfied that your roll works, create a pull request and land the roll using the normal process for contributing code to Flutter.