fix: race condition if a step run has multiple parents (#1095)

pkg/repository/prisma/step_run.go

@@ -2544,38 +2544,6 @@ func (s *stepRunEngineRepository) StepRunSucceeded(ctx context.Context, tenantId
 	ctx, span := telemetry.NewSpan(ctx, "step-run-started-db")
 	defer span.End()
 
-	finished := string(dbsqlc.StepRunStatusSUCCEEDED)
-
-	data := &updateStepRunQueueData{
-		Hash:       hashToBucket(sqlchelpers.UUIDFromStr(workflowRunId), s.maxHashFactor),
-		StepRunId:  stepRunId,
-		TenantId:   tenantId,
-		FinishedAt: &finishedAt,
-		Status:     &finished,
-		Output:     output,
-	}
-
-	// we write to the buffer first so we don't get race conditions when we resolve workflow run statuses
-	done, err := s.bulkStatusBuffer.BuffItem(tenantId, data)
-
-	if err != nil {
-		return fmt.Errorf("could not buffer step run succeeded: %w", err)
-	}
-
-	var response *buffer.FlushResponse[pgtype.UUID]
-
-	select {
-	case response = <-done:
-	case <-ctx.Done():
-		return ctx.Err()
-	case <-time.After(20 * time.Second):
-		return fmt.Errorf("timeout waiting for step run succeeded to be flushed to db")
-	}
-
-	if response.Err != nil {
-		return fmt.Errorf("could not flush step run succeeded: %w", response.Err)
-	}
-
 	tx, err := s.pool.Begin(ctx)
 
 	if err != nil {
@@ -2609,6 +2577,39 @@ func (s *stepRunEngineRepository) StepRunSucceeded(ctx context.Context, tenantId
 		return fmt.Errorf("could not commit transaction: %w", err)
 	}
 
+	finished := string(dbsqlc.StepRunStatusSUCCEEDED)
+
+	data := &updateStepRunQueueData{
+		Hash:       hashToBucket(sqlchelpers.UUIDFromStr(workflowRunId), s.maxHashFactor),
+		StepRunId:  stepRunId,
+		TenantId:   tenantId,
+		FinishedAt: &finishedAt,
+		Status:     &finished,
+		Output:     output,
+	}
+
+	// we write to the buffer after updating the job run lookup data so we don't start a step run (which has multiple
+	// parents) before the job run lookup data is updated
+	done, err := s.bulkStatusBuffer.BuffItem(tenantId, data)
+
+	if err != nil {
+		return fmt.Errorf("could not buffer step run succeeded: %w", err)
+	}
+
+	var response *buffer.FlushResponse[pgtype.UUID]
+
+	select {
+	case response = <-done:
+	case <-ctx.Done():
+		return ctx.Err()
+	case <-time.After(20 * time.Second):
+		return fmt.Errorf("timeout waiting for step run succeeded to be flushed to db")
+	}
+
+	if response.Err != nil {
+		return fmt.Errorf("could not flush step run succeeded: %w", response.Err)
+	}
+
 	return nil
 }