FRB Upgrade Flutter

Use this as the single-file workflow for Flutter stable bumps in flutter_rust_bridge.

Start Here

1. Confirm the target Flutter stable release from official Flutter sources.
2. Also read:
   • frb-docker before changing .devcontainer/** or publishing the dev image.
   • frb-code-generation before accepting generated or scaffold drift.
   • frb-cargokit or frb-cargokit-dev before changing copied cargokit files.
   • frb-pr-review before treating the upgrade PR as ready.
   • frb-fix-ci when CI starts failing.

Non-Negotiables

• Keep .github/workflows/ci.yaml and .github/workflows/post_release.yaml toolchain env values in sync.
• Treat .devcontainer/Dockerfile ARG values as the source of truth for dev image tags.
• Dry-run the dev Docker image before depending on a new derived image tag in the PR.
• After changing .devcontainer/Dockerfile, build a fresh local image from that Dockerfile and use a container based on that fresh image for local validation. Do not keep using an older per-worktree container whose Flutter, Dart, Rust, Android, or browser tooling may still be stale.
• After the upgrade PR merges, trigger the dev Docker image publish workflow on master.
• Do not hand-edit generated files as the final state.
• Classify scaffold drift by source: integration template, Apple scaffold, Cargokit, or example output.

Workflow

Step 1: Review the Flutter Release

Use official Flutter sources. Record the target Flutter version, bundled Dart version, release date, and release-note items likely to affect FRB.

Scan for:

• Dart SDK constraint changes
• Android Gradle Plugin, Kotlin, Java, Android SDK, or NDK changes
• iOS/macOS project generation changes, especially Swift Package Manager or CocoaPods defaults
• Web renderer, Chrome, DevTools, or test-driver changes
• Host architecture changes such as Apple Silicon or Windows ARM support

Step 2: Plan the Single Upgrade PR

Plan one PR for the Flutter upgrade. Keep the PR internally organized by logical commits or phases, but do not split the upgrade across multiple PRs unless Tom explicitly asks.

Use this order inside the single PR:

1. Upgrade the dev Docker image inputs and derived metadata tests.
2. Sync CI and post-release version pins.
3. Regenerate and classify scaffold drift.
4. Fix real compatibility failures.
5. Update workflow docs or skills only if the process changed.

Step 3: Inventory Current Pins

Run these before planning the bump:

rg -n \
  "FRB_MAIN_|FLUTTER_VERSION|DART_VERSION|RUST_VERSION|setup-flutter|setup-dart|cirruslabs/flutter"
rg -n "flutter_rust_bridge_dev|3\\.[0-9]+"

Inspect at least:

• .devcontainer/Dockerfile
• .github/workflows/ci.yaml
• .github/workflows/post_release.yaml
• .github/workflows/publish_dev_docker.yaml
• tools/frb_internal/test/src/makefile_dart/test_dev_docker_metadata.dart
• pubspec.yaml, package pubspec.yaml files, and checked-in pubspec.lock files
• frb_codegen/assets/integration_template/**
• tools/frb_internal/assets/apple_scaffold/**
• frb_example/**

Step 4: Upgrade the Devcontainer First

Update .devcontainer/Dockerfile:

• ARG FLUTTER_VERSION
• Required Rust, Rust nightly, Node, Playwright, Chrome, system package, Java, or Android tooling changes

Update metadata tests that assert the derived dev image tag.

Build and smoke-test locally when practical. If an old per-worktree container already exists, do not use it for this step; create a fresh container from the newly built image, or rebuild/recreate the per-worktree container so it uses the updated Dockerfile contents.

docker build -f .devcontainer/Dockerfile -t frb-dev .devcontainer
docker run --rm -v "$PWD:/workspace" -w /workspace frb-dev bash -lc './frb_internal --help'
docker run --rm -v "$PWD:/workspace" -w /workspace frb-dev bash -lc '
set -euo pipefail
flutter --version
dart --version
node --version
npm --version
cargo --version
wasm-pack --version
"${CHROME_BIN}" --version
'

If local build is too expensive, dry-run the workflow:

gh workflow run publish_dev_docker.yaml --ref <branch> -f publish=false

Step 5: Sync CI and Post-Release Pins

Update top-level env values together in .github/workflows/ci.yaml and .github/workflows/post_release.yaml:

• FRB_MAIN_FLUTTER_VERSION
• FRB_MAIN_DART_VERSION
• FRB_MAIN_RUST_VERSION if the Flutter or tooling bump requires newer Rust
• FRB_RUSTFMT_NIGHTLY_VERSION only if formatting or nightly-only rust-src behavior requires it

post_release.yaml intentionally says it should stay in sync with ci.yaml. It verifies released quickstart and codegen installation modes, so do not leave it pinned to old Flutter/Dart versions.

Scan workflow assumptions:

• flutter-actions/setup-flutter
• dart-lang/setup-dart
• Java setup for Android jobs
• Linux desktop package prerequisites
• iOS simulator names and macOS runner labels
• Windows ARM runner coverage
• Chrome/chromedriver setup for web jobs
• Post-release codegen_install_mode coverage for cargo-install, cargo-binstall, scoop, and homebrew
• Any commented job that says it was waiting for a CI Flutter upgrade

Step 6: Regenerate and Classify Drift

Read frb-code-generation first.

Expect drift in:

• pubspec.lock Dart SDK constraints
• flutter create / flutter integrate scaffold output
• Android Gradle, Kotlin, Java, NDK, and manifest files
• iOS/macOS Xcode project files, CocoaPods files, or SwiftPM package files
• Windows/Linux desktop scaffold files
• Generated frb_generated.* files if Dart formatting, analyzer behavior, or codegen dependencies changed

Classify by source:

• Template-driven drift belongs in frb_codegen/assets/integration_template/**.
• Apple scaffold drift may belong in tools/frb_internal/assets/apple_scaffold/**.
• Cargokit drift may belong in the upstream Cargokit repo.
• Example-only drift should come from the relevant ./frb_internal generate-* or precommit-* command.

Run focused generation first when possible, then broaden:

./frb_internal precommit-generate
./frb_internal precommit-integrate

If multiple generated-output CI failures rotate across packages, stop package-by-package fixes and run a clean full ./frb_internal precommit-generate.

Step 7: Validate Locally

Read frb-lint and frb-test for exact command guidance. Tom's FRB environment runs tests locally, usually through the per-worktree Docker container.

If the Flutter upgrade changed .devcontainer/Dockerfile, first ensure local validation is running inside the fresh image built in Step 4. Seeing an old Dart or Flutter version locally means the container is stale; recreate it before trusting any validation result.

Recommended minimum validation:

./frb_internal lint --fix
./frb_internal test-dart-native --package frb_example/pure_dart
./frb_internal test-dart-native --package frb_example/pure_dart_pde
./frb_internal test-flutter-native --package frb_example/flutter_via_create
./frb_internal test-flutter-web --package frb_example/gallery

For CI or Docker plumbing-only changes, dev image dry-run and focused metadata tests may be enough before opening the PR. Let CI cover the full matrix.

Before treating the upgrade PR as ready, run the review gate in frb-pr-review.

Step 8: Triage CI in Dependency Order

Read frb-fix-ci before deep debugging.

1. Dev Docker publish or dry-run failures
2. Lint/setup failures caused by incompatible tool versions
3. Generate and Generate Internal failures
4. Integrate scaffold failures
5. Build and platform tests
6. Post-release quickstart failures
7. Coverage, benchmark, website, and upload jobs

When a platform starts failing after the Flutter bump, compare against release notes before patching symptoms. Flutter stable bumps often intentionally change generated platform projects.

Step 9: Publish the Dev Docker Image After Merge

After the single upgrade PR is merged into master, trigger the publish workflow from master so the new derived dev image tag exists for future CI and developer workflows:

gh workflow run publish_dev_docker.yaml --ref master

After it completes, verify both linux/amd64 and linux/arm64:

docker buildx imagetools inspect fzyzcjy/flutter_rust_bridge_dev:latest
docker buildx imagetools inspect fzyzcjy/flutter_rust_bridge_dev:flutter-<flutter>-rust-<rust>-nightly-<nightly>

BuildKit attestation manifests can appear as unknown/unknown; those are not platform images.

PR Notes

For the single upgrade PR, include:

• Old and new Flutter/Dart versions
• Whether the dev image was dry-run or published
• Exact version tag of the dev image
• Generated/scaffold sources that changed
• Local validation commands and CI status
• Any known remaining platform-specific follow-up