From f189551c563da07fd006d1cb95903c0588e5485d Mon Sep 17 00:00:00 2001
From: Dark Knight <generatedunixname89002005232357@meta.com>
Date: Thu, 10 Apr 2025 06:15:42 -0700
Subject: [PATCH] Revert D72722867: Multisect successfully blamed "D72475332:
 [torchcodec][diff_train] Make device interface generic (#606)" for one test
 failure

Summary:
This diff reverts D72722867
D72475332: [torchcodec][diff_train] Make device interface generic (#606) by generatedunixname499836121 causes the following test failure:

Tests affected:
- [cogwheel:cogwheel_fblearner_inferno_hello_world#main](https://www.internalfb.com/intern/test/844425115815788/)

Here's the Multisect link:
https://www.internalfb.com/multisect/25810176
Here are the tasks that are relevant to this breakage:
T191383700: 100+ tests, 10+ build rules, some CI signals unhealthy for offline_inference

The backout may land if someone accepts it.

If this diff has been generated in error, you can Commandeer and Abandon it.

Reviewed By: scotts

Differential Revision: D72775487
---
 src/torchcodec/_core/DeviceInterface.cpp | 27 +++++++-----------------
 1 file changed, 8 insertions(+), 19 deletions(-)

diff --git a/src/torchcodec/_core/DeviceInterface.cpp b/src/torchcodec/_core/DeviceInterface.cpp
index 382de6217..7612334b1 100644
--- a/src/torchcodec/_core/DeviceInterface.cpp
+++ b/src/torchcodec/_core/DeviceInterface.cpp
@@ -11,9 +11,8 @@
 namespace facebook::torchcodec {
 
 namespace {
-using DeviceInterfaceMap = std::map<torch::DeviceType, CreateDeviceInterfaceFn>;
 std::mutex g_interface_mutex;
-std::unique_ptr<DeviceInterfaceMap> g_interface_map;
+std::map<torch::DeviceType, CreateDeviceInterfaceFn> g_interface_map;
 
 std::string getDeviceType(const std::string& device) {
   size_t pos = device.find(':');
@@ -29,18 +28,11 @@ bool registerDeviceInterface(
     torch::DeviceType deviceType,
     CreateDeviceInterfaceFn createInterface) {
   std::scoped_lock lock(g_interface_mutex);
-  if (!g_interface_map) {
-    // We delay this initialization until runtime to avoid the Static
-    // Initialization Order Fiasco:
-    //
-    //   https://en.cppreference.com/w/cpp/language/siof
-    g_interface_map = std::make_unique<DeviceInterfaceMap>();
-  }
   TORCH_CHECK(
-      g_interface_map->find(deviceType) == g_interface_map->end(),
+      g_interface_map.find(deviceType) == g_interface_map.end(),
       "Device interface already registered for ",
       deviceType);
-  g_interface_map->insert({deviceType, createInterface});
+  g_interface_map.insert({deviceType, createInterface});
   return true;
 }
 
@@ -53,16 +45,14 @@ torch::Device createTorchDevice(const std::string device) {
   std::scoped_lock lock(g_interface_mutex);
   std::string deviceType = getDeviceType(device);
   auto deviceInterface = std::find_if(
-      g_interface_map->begin(),
-      g_interface_map->end(),
+      g_interface_map.begin(),
+      g_interface_map.end(),
       [&](const std::pair<torch::DeviceType, CreateDeviceInterfaceFn>& arg) {
         return device.rfind(
                    torch::DeviceTypeName(arg.first, /*lcase*/ true), 0) == 0;
       });
   TORCH_CHECK(
-      deviceInterface != g_interface_map->end(),
-      "Unsupported device: ",
-      device);
+      deviceInterface != g_interface_map.end(), "Unsupported device: ", device);
 
   return torch::Device(device);
 }
@@ -77,12 +67,11 @@ std::unique_ptr<DeviceInterface> createDeviceInterface(
 
   std::scoped_lock lock(g_interface_mutex);
   TORCH_CHECK(
-      g_interface_map->find(deviceType) != g_interface_map->end(),
+      g_interface_map.find(deviceType) != g_interface_map.end(),
       "Unsupported device: ",
       device);
 
-  return std::unique_ptr<DeviceInterface>(
-      (*g_interface_map)[deviceType](device));
+  return std::unique_ptr<DeviceInterface>(g_interface_map[deviceType](device));
 }
 
 } // namespace facebook::torchcodec