Don't crash if a metagraph fails to load.

PiperOrigin-RevId: 159981628

2 files changed, 5 insertions, 2 deletions

diff --git a/tensorflow/core/grappler/grappler_item_builder.cc b/tensorflow/core/grappler/grappler_item_builder.cc
index 969376917b..c6e3bc626e 100644
--- a/tensorflow/core/grappler/grappler_item_builder.cc
+++ b/tensorflow/core/grappler/grappler_item_builder.cc
@@ -328,7 +328,7 @@ std::unique_ptr<GrapplerItem> GrapplerItemFromMetaGraphDef(
   Status optimize_status =
       OptimizeGraph(new_item->graph, &new_item->graph, cfg);
   if (!optimize_status.ok()) {
-    LOG(ERROR) << "Function optimization failed: " << optimize_status;
+    LOG(ERROR) << "Graph preprocessing failed: " << optimize_status;
     return nullptr;
   }
 
diff --git a/tensorflow/python/grappler/cost_analyzer.i b/tensorflow/python/grappler/cost_analyzer.i
index 6066b6131f..1f024e439d 100644
--- a/tensorflow/python/grappler/cost_analyzer.i
+++ b/tensorflow/python/grappler/cost_analyzer.i
@@ -48,7 +48,10 @@ per_node_report) {
   cfg.apply_optimizations = false;
   std::unique_ptr<tensorflow::grappler::GrapplerItem> item =
       tensorflow::grappler::GrapplerItemFromMetaGraphDef("metagraph", metagraph, cfg);
-
+  if (!item) {
+    return "Error: failed to preprocess metagraph: check your log file for errors";
+  }
+  
   // TODO(bsteiner): we should wrap the tf session instead to properly handle the case of a
   // distributed setup.
   const int timeout_s = 3600;