From d8f67f03e4e444a10e5b34c2bcb2b3c726d29377 Mon Sep 17 00:00:00 2001
From: Will Cromar <wcromar@google.com>
Date: Mon, 16 Oct 2023 10:35:14 -0700
Subject: [PATCH] Don't set $TPU_LIBRARY_PATH during import (#5698)

* Don't set $TPU_LIBRARY_PATH during import

* remove chekck for new env var so people don't use it
---
 torch_xla/__init__.py                             | 9 ++++++---
 torch_xla/csrc/runtime/env_vars.cc                | 1 +
 torch_xla/csrc/runtime/env_vars.h                 | 1 +
 torch_xla/csrc/runtime/pjrt_computation_client.cc | 9 +++++----
 4 files changed, 13 insertions(+), 7 deletions(-)

diff --git a/torch_xla/__init__.py b/torch_xla/__init__.py
index eeaa2aaba0c..ce1787d0fe3 100644
--- a/torch_xla/__init__.py
+++ b/torch_xla/__init__.py
@@ -72,13 +72,16 @@ def _aws_ec2_inf_trn_init():
 
 
 def _setup_tpu_vm_library_path() -> bool:
-  """Returns true if $TPU_LIBRARY is set or can be inferred.
+  """Returns true if $TPU_LIBRARY_PATH is set or can be inferred.
 
   We load libtpu.so in the following order of precedence:
 
   1. User-set $TPU_LIBRARY_PATH
   2. libtpu.so included in torch_xla/lib
   3. libtpu-nightly pip package
+
+  Sets $PTXLA_TPU_LIBRARY_PATH if path is inferred by us to prevent conflicts
+  with other frameworks. This env var will be removed in a future version.
   """
   if 'TPU_LIBRARY_PATH' in os.environ:
     return True
@@ -87,12 +90,12 @@ def _setup_tpu_vm_library_path() -> bool:
   bundled_libtpu_path = os.path.join(module_path, 'lib/libtpu.so')
   if os.path.isfile(bundled_libtpu_path) and not os.getenv('TPU_LIBRARY_PATH'):
     logger.info('Using bundled libtpu.so (%s)', bundled_libtpu_path)
-    os.environ['TPU_LIBRARY_PATH'] = bundled_libtpu_path
+    os.environ['PTXLA_TPU_LIBRARY_PATH'] = bundled_libtpu_path
     return True
 
   try:
     import libtpu
-    libtpu.configure_library_path()
+    os.environ['PTXLA_TPU_LIBRARY_PATH'] = libtpu.get_library_path()
     return True
   except ImportError:
     return False
diff --git a/torch_xla/csrc/runtime/env_vars.cc b/torch_xla/csrc/runtime/env_vars.cc
index 42040a9cca5..00ffb1f2a25 100644
--- a/torch_xla/csrc/runtime/env_vars.cc
+++ b/torch_xla/csrc/runtime/env_vars.cc
@@ -14,6 +14,7 @@ const char* const kEnvPjRtTpuMaxInflightComputations =
 const char* const kEnvPjrtAsyncCpuClient = "PJRT_CPU_ASYNC_CLIENT";
 const char* const kEnvPjrtAsyncGpuClient = "PJRT_GPU_ASYNC_CLIENT";
 const char* const kEnvTpuLibraryPath = "TPU_LIBRARY_PATH";
+const char* const kEnvInferredTpuLibraryPath = "PTXLA_TPU_LIBRARY_PATH";
 const char* const kEnvXpuLibraryPath = "XPU_LIBRARY_PATH";
 const char* const kEnvNeuronLibraryPath = "NEURON_LIBRARY_PATH";
 const char* const kEnvPjrtDistServiceAddr = "PJRT_DIST_SERVICE_ADDR";
diff --git a/torch_xla/csrc/runtime/env_vars.h b/torch_xla/csrc/runtime/env_vars.h
index e54ba8f72cd..72849003765 100644
--- a/torch_xla/csrc/runtime/env_vars.h
+++ b/torch_xla/csrc/runtime/env_vars.h
@@ -24,6 +24,7 @@ extern const char* const kEnvPjRtTpuMaxInflightComputations;
 extern const char* const kEnvPjrtAsyncCpuClient;
 extern const char* const kEnvPjrtAsyncGpuClient;
 extern const char* const kEnvTpuLibraryPath;
+extern const char* const kEnvInferredTpuLibraryPath;
 extern const char* const kEnvXpuLibraryPath;
 extern const char* const kEnvNeuronLibraryPath;
 extern const char* const kEnvPjrtDistServiceAddr;
diff --git a/torch_xla/csrc/runtime/pjrt_computation_client.cc b/torch_xla/csrc/runtime/pjrt_computation_client.cc
index 237531d43cf..a4a8af1ac9e 100644
--- a/torch_xla/csrc/runtime/pjrt_computation_client.cc
+++ b/torch_xla/csrc/runtime/pjrt_computation_client.cc
@@ -109,10 +109,11 @@ PjRtComputationClient::PjRtComputationClient() {
     client_ = std::move(xla::GetTfrtCpuClient(async, cpu_device_count).value());
   } else if (device_type == "TPU" || device_type == "TPU_C_API") {
     TF_VLOG(1) << "Initializing TFRT TPU client...";
-    XLA_CHECK_OK(
-        pjrt::LoadPjrtPlugin(
-            "tpu", sys_util::GetEnvString(env::kEnvTpuLibraryPath, "libtpu.so"))
-            .status());
+    // Prefer $TPU_LIBRARY_PATH if set
+    auto tpu_library_path = sys_util::GetEnvString(
+        env::kEnvTpuLibraryPath,
+        sys_util::GetEnvString(env::kEnvInferredTpuLibraryPath, "libtpu.so"));
+    XLA_CHECK_OK(pjrt::LoadPjrtPlugin("tpu", tpu_library_path).status());
     tsl::Status tpu_status = pjrt::InitializePjrtPlugin("tpu");
     XLA_CHECK(tpu_status.ok());
     client_ = std::move(xla::GetCApiClient("TPU").value());