Read LUCI additional build details only in unified check run flow

app_dart/lib/src/request_handlers/presubmit_luci_subscription.dart

@@ -77,7 +77,7 @@ final class PresubmitLuciSubscription extends SubscriptionHandler {
       return Response.emptyOk;
     }
 
-    final build = buildsPubSub.build;
+    var build = buildsPubSub.build;
 
     // Add build fields that are stored in a separate compressed buffer.
     build.mergeFromBuffer(ZLibCodec().decode(buildsPubSub.buildLargeFields));
@@ -104,14 +104,17 @@ final class PresubmitLuciSubscription extends SubscriptionHandler {
     var rescheduled = false;
     final isUnifiedCheckRun = userData.guardCheckRunId != null;
     if (build.status.isTaskFailed()) {
-      // if failed summary stored in github check run and unified check run.
-      build.summaryMarkdown = (await _luciBuildService.getBuildById(
-        build.id,
-        buildMask: bbv2.BuildMask(
-          // Need to use allFields as there is a bug with fieldMask and summaryMarkdown.
-          allFields: true,
-        ),
-      )).summaryMarkdown;
+      if (isUnifiedCheckRun) {
+        // If failed we need summaryMarkdown. For github check run flow this
+        // called in [GithubChecksService.updateCheckStatus(...)]
+        build = await _luciBuildService.getBuildById(
+          build.id,
+          buildMask: bbv2.BuildMask(
+            // Need to use allFields as there is a bug with fieldMask and summaryMarkdown.
+            allFields: true,
+          ),
+        );
+      }
       final maxAttempt = await _getMaxAttempt(
         userData.commit,
         builderName,

app_dart/lib/src/service/flags/unified_check_run_flow_flags.dart

@@ -18,7 +18,7 @@ final class UnifiedCheckRunFlow {
   );
 
   /// Whether to use unified check-run flow with only one check-run created
-  /// for all LUCI tests or legacy check-run flow.
+  /// for all LUCI tests or github check-run flow.
   @JsonKey()
   final bool useForAll;
 

app_dart/lib/src/service/scheduler.dart

@@ -948,7 +948,7 @@ $s
     if (kCheckRunsToIgnore.contains(check.name)) {
       return true;
     }
-    final flow = check.isUnifiedCheckRun ? 'unified' : 'legacy';
+    final flow = check.isUnifiedCheckRun ? 'unified' : 'github';
     final requestor = check.isMergeGroup ? 'merge group' : 'pull request';
     final logCrumb =
         'checkCompleted(${check.name}, $flow, $requestor, ${check.slug}, ${check.sha}, ${check.status})';