Always provide a git SHA of an engine to use if the try-bots built the engine for the commit (#4845)
https://github.com/flutter/cocoon/pull/4844 was partially correct.
However, PRs such as https://github.com/flutter/flutter/pull/174310 are still blocked because they touch the engine, and try-bots (as of currently) only upload engines to a git SHA, not a content hash. This PR relaxes the try-bot logic to continue to provide the current SHA as "this is the engine" if the engine is being built from source.
Implicitly, it will no longer provide `FLUTTER_PREBUILT_ENGINE_VERSION=` for the `master` branch, if and only if the engine is not being touched. That means `flutter <any command>` will start to download the engine using the content hash, which should be fine.
diff --git a/app_dart/lib/src/service/luci_build_service.dart b/app_dart/lib/src/service/luci_build_service.dart
index abb6a03..d502297 100644
--- a/app_dart/lib/src/service/luci_build_service.dart
+++ b/app_dart/lib/src/service/luci_build_service.dart
@@ -284,8 +284,10 @@
switch (engineArtifacts) {
case SpecifiedEngineArtifacts(:final commitSha, :final flutterRealm):
properties.addAll({
- // For release candidates, let the flutter tool pick the right engine.
- if (!isReleaseCandidateBranch(branchName: commitBranch))
+ // If we've touched the engine, we must use the current git sha's uploaded engine artifacts.
+ // Otherwise, let the flutter tool find the previously built artfiacts (using content-aware hashing).
+ // TODO(matanlurey): Review with jtmcdole to ensure this is correct.
+ if (engineArtifacts.isBuiltFromSource)
'flutter_prebuilt_engine_version': commitSha,
'flutter_realm': flutterRealm,
});
diff --git a/app_dart/test/service/luci_build_service/schedule_try_builds_test.dart b/app_dart/test/service/luci_build_service/schedule_try_builds_test.dart
index 4da4792..9e8986a 100644
--- a/app_dart/test/service/luci_build_service/schedule_try_builds_test.dart
+++ b/app_dart/test/service/luci_build_service/schedule_try_builds_test.dart
@@ -234,7 +234,6 @@
'exe_cipd_version': bbv2.Value(stringValue: 'refs/heads/main'),
'recipe': bbv2.Value(stringValue: 'devicelab/devicelab'),
'is_fusion': bbv2.Value(stringValue: 'true'),
- 'flutter_prebuilt_engine_version': bbv2.Value(stringValue: 'basesha123'),
'flutter_realm': bbv2.Value(stringValue: ''),
});
expect(scheduleBuild.dimensions, [
