From 07e7033076d9acfeeaa7a91ea878fa130a022824 Mon Sep 17 00:00:00 2001
From: Behdad Esfahbod <behdad@behdad.org>
Date: Tue, 1 Aug 2023 12:25:45 -0600
Subject: [PATCH] [graph] Error check

---
 src/graph/graph.hh | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/src/graph/graph.hh b/src/graph/graph.hh
index e464d1746..18f329b64 100644
--- a/src/graph/graph.hh
+++ b/src/graph/graph.hh
@@ -280,7 +280,8 @@ struct graph_t
       for (auto _ : parents)
         new_parents.set (id_map[_.first], _.second);
 
-      parents = std::move (new_parents);
+      if (!new_parents.in_error ())
+	parents = std::move (new_parents);
     }
 
     void remap_parent (unsigned old_index, unsigned new_index)