Fix hosted engine Rust and web SDK setup

.github/workflows/open-shorebird-ci.yml

@@ -921,6 +921,9 @@ jobs:
           distribution: temurin
           java-version: ${{ env.JAVA_VERSION }}
 
+      - name: Install Android Rust target
+        run: rustup target add aarch64-linux-android
+
       - name: Free Ubuntu runner disk
         run: ./scripts/free_ci_disk_linux.sh
 
@@ -1108,6 +1111,9 @@ jobs:
         working-directory: flutter
         run: gclient sync --no-history
 
+      - name: Sync Flutter prebuilt Dart SDK
+        run: ./scripts/sync_flutter_prebuilt_dart_sdk.sh linux-x64
+
       - name: Configure web SDK
         working-directory: flutter/engine/src
         run: |
@@ -1115,8 +1121,7 @@ jobs:
             --web \
             --runtime-mode=release \
             --target-dir=wasm_release \
-            --no-prebuilt-dart-sdk \
-            --gn-args='dart_dynamic_modules=false flutter_prebuilt_dart_sdk=false'
+            --gn-args='dart_dynamic_modules=false'
 
       - name: Build web SDK
         working-directory: flutter/engine/src
@@ -1127,7 +1132,7 @@ jobs:
           ./scripts/verify_engine_args.sh \
             flutter/engine/src/out/wasm_release/args.gn \
             dart_dynamic_modules=false \
-            flutter_prebuilt_dart_sdk=false
+            flutter_prebuilt_dart_sdk=true
 
       - name: Package web SDK artifact
         run: |
@@ -1206,6 +1211,9 @@ jobs:
           gclient help >/dev/null
           ninja --version
 
+      - name: Install Apple Rust targets
+        run: rustup target add aarch64-apple-ios aarch64-apple-darwin
+
       - name: Check runner capacity
         run: CI_MIN_FREE_DISK_GB="$ENGINE_MIN_FREE_DISK_GB" ./scripts/check_ci_capacity.sh
 

docs/CI.md

@@ -441,15 +441,17 @@ verifies the Android artifacts/symbols zips, `flutter.jar`, `libflutter.so`,
 host snapshot/analyzer tools, args file, manifest, and mirror subtree.
 
 `web-sdk` builds the Flutter web SDK archive from `wasm_release` with
-`dart_dynamic_modules=false` and `flutter_prebuilt_dart_sdk=false`, then uploads
+`dart_dynamic_modules=false` and `flutter_prebuilt_dart_sdk=true`, then uploads
 `flutter-web-sdk.zip`, a mirror-ready copy of that SDK archive, `args.gn`, a
-manifest with the Flutter engine revision, and a `.sha256` sidecar. The engine
-and web jobs use `--no-prebuilt-dart-sdk` because the open workspace disables
-Flutter's private prebuilt Dart SDK download path and builds from the linked
-Dart checkout instead. Web is still not a Shorebird CodePush release platform
-in this CLI/protocol; this job exists to keep the open Flutter SDK/web artifacts
-buildable from the workspace. CI extracts the web SDK archive before upload and
-verifies the SDK zip, args file, manifest, and mirror subtree.
+manifest with the Flutter engine revision, and a `.sha256` sidecar. The web job
+does not download Flutter's private prebuilt Dart SDK; it links
+`dart-sdk/tools/sdks/dart-sdk` into Flutter's expected prebuilt path before
+running GN. Native engine jobs use `--no-prebuilt-dart-sdk` because the open
+workspace builds those SDK artifacts from the linked Dart checkout instead. Web
+is still not a Shorebird CodePush release platform in this CLI/protocol; this
+job exists to keep the open Flutter SDK/web artifacts buildable from the
+workspace. CI extracts the web SDK archive before upload and verifies the SDK
+zip, args file, manifest, and mirror subtree.
 
 Set `run_gclient_sync=false` only for debugging a runner image that already has
 all gclient-managed dependencies restored.

scripts/sync_flutter_prebuilt_dart_sdk.sh

@@ -0,0 +1,67 @@
+#!/usr/bin/env bash
+set -euo pipefail
+
+ROOT="$(cd "$(dirname "${BASH_SOURCE[0]}")/.." && pwd)"
+HOST_CONFIG="${1:-linux-x64}"
+DART_SDK_SOURCE="${DART_SDK_SOURCE:-$ROOT/dart-sdk/tools/sdks/dart-sdk}"
+TARGET="$ROOT/flutter/engine/src/flutter/prebuilts/$HOST_CONFIG/dart-sdk"
+
+relative_path() {
+  python3 - "$1" "$2" <<'PY'
+import os
+import sys
+print(os.path.relpath(sys.argv[2], os.path.dirname(sys.argv[1])))
+PY
+}
+
+real_path() {
+  python3 - "$1" <<'PY'
+import os
+import sys
+print(os.path.realpath(sys.argv[1]))
+PY
+}
+
+case "$HOST_CONFIG" in
+  linux-x64|macos-x64|macos-arm64)
+    ;;
+  *)
+    echo "unsupported Flutter prebuilt Dart SDK host config: $HOST_CONFIG" >&2
+    exit 64
+    ;;
+esac
+
+if [[ ! -d "$DART_SDK_SOURCE" ]]; then
+  echo "missing Dart tool SDK source: $DART_SDK_SOURCE" >&2
+  exit 66
+fi
+
+for required in \
+  bin/dart \
+  bin/dartaotruntime \
+  bin/snapshots/dartdevc_aot.dart.snapshot \
+  bin/snapshots/kernel_worker_aot.dart.snapshot
+do
+  if [[ ! -e "$DART_SDK_SOURCE/$required" ]]; then
+    echo "Dart tool SDK is missing $required: $DART_SDK_SOURCE" >&2
+    exit 66
+  fi
+done
+
+mkdir -p "$(dirname "$TARGET")"
+
+if [[ -L "$TARGET" ]]; then
+  source_real="$(real_path "$DART_SDK_SOURCE")"
+  target_real="$(real_path "$TARGET")"
+  if [[ "$source_real" != "$target_real" ]]; then
+    echo "Flutter prebuilt Dart SDK link points at $target_real, expected $source_real" >&2
+    exit 70
+  fi
+elif [[ -e "$TARGET" ]]; then
+  echo "Flutter prebuilt Dart SDK target exists but is not the workspace Dart tool SDK symlink: $TARGET" >&2
+  exit 70
+else
+  ln -s "$(relative_path "$TARGET" "$DART_SDK_SOURCE")" "$TARGET"
+fi
+
+echo "[open-source-sync] Flutter $HOST_CONFIG prebuilt Dart SDK uses $DART_SDK_SOURCE"

scripts/verify_ci_workflow.rb

@@ -136,6 +136,7 @@ required_files = %w[
   scripts/linux_runtime_patch_smoke.sh
   scripts/verify_open_infrastructure_defaults.sh
   scripts/safe_extract_tar.py
+  scripts/sync_flutter_prebuilt_dart_sdk.sh
   scripts/sync_open_sources.sh
   scripts/validate_artifact_mirror.py
   scripts/validate_release_manifest.py
@@ -1023,6 +1024,10 @@ platform_test_common = read_repo_file(repo_root, 'scripts/platform_test_common.s
 bootstrap_linux = read_repo_file(repo_root, 'scripts/bootstrap_linux.sh')
 bootstrap_macos = read_repo_file(repo_root, 'scripts/bootstrap_macos.sh')
 sync_open_sources = read_repo_file(repo_root, 'scripts/sync_open_sources.sh')
+sync_flutter_prebuilt_dart_sdk = read_repo_file(
+  repo_root,
+  'scripts/sync_flutter_prebuilt_dart_sdk.sh'
+)
 verify_sync_open_sources = read_repo_file(
   repo_root,
   'scripts/verify_sync_open_sources.sh'
@@ -1133,6 +1138,15 @@ assert!(
     verify_sync_open_sources.include?('expected forbidden explicit UPDATER_URL to fail'),
   'source sync smoke test must reject upstream Dart SDK and official Shorebird updater remotes'
 )
+assert!(
+  sync_flutter_prebuilt_dart_sdk.include?('dart-sdk/tools/sdks/dart-sdk') &&
+    sync_flutter_prebuilt_dart_sdk.include?('flutter/engine/src/flutter/prebuilts/$HOST_CONFIG/dart-sdk') &&
+    sync_flutter_prebuilt_dart_sdk.include?('bin/dartaotruntime') &&
+    sync_flutter_prebuilt_dart_sdk.include?('bin/snapshots/kernel_worker_aot.dart.snapshot') &&
+    sync_flutter_prebuilt_dart_sdk.include?('ln -s') &&
+    !sync_flutter_prebuilt_dart_sdk.include?('shorebird-dart-sdk-prebuilt'),
+  'Flutter web prebuilt Dart SDK sync must link the open Dart tool SDK into Flutter prebuilts'
+)
 assert!(
   job_runs(jobs.fetch('source-checks')).join("\n").include?('./scripts/verify_release_manifest.sh'),
   'source-checks must smoke-test release manifest validation'
@@ -1941,6 +1955,7 @@ end
 
 assert!(
   run_text_by_job.fetch('ios-engine').include?('--shorebird-interpreter') &&
+    run_text_by_job.fetch('ios-engine').include?('rustup target add aarch64-apple-ios aarch64-apple-darwin') &&
     run_text_by_job.fetch('ios-engine').include?('--no-prebuilt-dart-sdk') &&
     run_text_by_job.fetch('ios-engine').include?("--gn-args='dart_dynamic_modules=false dart_enable_aot_patching=true dart_enable_shorebird_interpreter=true shorebird_use_interpreter=true flutter_prebuilt_dart_sdk=false'") &&
     run_text_by_job.fetch('ios-engine').include?("--gn-args='flutter_prebuilt_dart_sdk=false'") &&
@@ -2008,6 +2023,7 @@ assert!(
 )
 assert!(
   run_text_by_job.fetch('android-engine').include?('verify_engine_args.sh') &&
+    run_text_by_job.fetch('android-engine').include?('rustup target add aarch64-linux-android') &&
     run_text_by_job.fetch('android-engine').include?('--no-prebuilt-dart-sdk') &&
     run_text_by_job.fetch('android-engine').include?('flutter/engine/src/out/android_release_arm64/args.gn') &&
     run_text_by_job.fetch('android-engine').include?('dart_enable_aot_patching=true') &&
@@ -2021,10 +2037,10 @@ assert!(
 )
 assert!(
   run_text_by_job.fetch('web-sdk').include?('verify_engine_args.sh') &&
-    run_text_by_job.fetch('web-sdk').include?('--no-prebuilt-dart-sdk') &&
+    run_text_by_job.fetch('web-sdk').include?('sync_flutter_prebuilt_dart_sdk.sh linux-x64') &&
     run_text_by_job.fetch('web-sdk').include?('flutter/engine/src/out/wasm_release/args.gn') &&
     run_text_by_job.fetch('web-sdk').include?('dart_dynamic_modules=false') &&
-    run_text_by_job.fetch('web-sdk').include?('flutter_prebuilt_dart_sdk=false') &&
+    run_text_by_job.fetch('web-sdk').include?('flutter_prebuilt_dart_sdk=true') &&
     run_text_by_job.fetch('web-sdk').include?('mirror/shorebird/flutter_infra_release/flutter/${engine_revision}/flutter-web-sdk.zip'),
   'web SDK job must explicitly disable and verify DDM'
 )