Fix bad error message when PjRtComputationClient throws exception

torch_xla/csrc/runtime/runtime.cc

@@ -10,38 +10,37 @@ namespace torch_xla {
 namespace runtime {
 namespace {
 
-std::atomic<bool> g_computation_client_initialized(false);
-
-ComputationClient* CreateClient() {
-  bool was_initialized = g_computation_client_initialized.exchange(true);
-  XLA_CHECK(!was_initialized) << "ComputationClient already initialized";
+std::unique_ptr<ComputationClient> CreateClient() {
   if (sys_util::GetEnvBool("XLA_DUMP_FATAL_STACK", false)) {
     tsl::testing::InstallStacktraceHandler();
   }
 
-  ComputationClient* client;
+  std::unique_ptr<ComputationClient> client = nullptr;
 
   if (sys_util::GetEnvString(env::kEnvPjRtDevice, "") != "") {
-    client = new PjRtComputationClient();
+    client = std::make_unique<PjRtComputationClient>();
   } else {
-    g_computation_client_initialized = false;
     XLA_ERROR() << "$PJRT_DEVICE is not set." << std::endl;
   }
 
-  XLA_CHECK(client != nullptr);
+  XLA_CHECK(client);
 
   return client;
 }
 
 }  // namespace
 
-ComputationClient* GetComputationClient() {
-  static auto client = std::unique_ptr<ComputationClient>(CreateClient());
+ComputationClient* GetComputationClient(bool create) {
+  static std::unique_ptr<ComputationClient> client = nullptr;
+  if (!client && create) {
+    static std::once_flag flag;
+    std::call_once(flag, []() { client = CreateClient(); });
+  }
   return client.get();
 }
 
 ComputationClient* GetComputationClientIfInitialized() {
-  return g_computation_client_initialized ? GetComputationClient() : nullptr;
+  return GetComputationClient(/*create=*/false);
 }
 
 }  // namespace runtime

torch_xla/csrc/runtime/runtime.h

@@ -7,7 +7,7 @@ namespace torch_xla {
 namespace runtime {
 
 // Returns the ComputationClient singleton.
-ComputationClient* GetComputationClient();
+ComputationClient* GetComputationClient(bool create = true);
 
 ComputationClient* GetComputationClientIfInitialized();