Revert "c10d/Store: add clone feature (#150966)"

This reverts commit 205881ea4a.

Reverted https://github.com/pytorch/pytorch/pull/150966 on behalf of https://github.com/atalman due to failing internally ([comment](https://github.com/pytorch/pytorch/pull/150966#issuecomment-2795063574))

test/distributed/test_store.py

@@ -172,15 +172,6 @@ class StoreTestBase:
     def test_multi_get(self):
         self._test_multi_get(self._create_store())
 
-    def test_clone(self):
-        a = self._create_store()
-        b = a.clone()
-
-        self.assertIsInstance(b, dist.Store)
-
-        a.set("foo", "bar")
-        self.assertEqual(b.get("foo"), b"bar")
-
     # This is the number of keys used in test_set_get. Adding this as a class
     # property instead of hardcoding in the test since some Store
     # implementations will have differing number of keys. In the base case,
@@ -637,9 +628,6 @@ class MyPythonStore(dist.Store):
             val = self.store[key] = newValue
         return val
 
-    def clone(self) -> "MyPythonStore":
-        return self
-
 
 class PythonStoreTest(TestCase):
     def test_set_get(self):

torch/csrc/distributed/c10d/FileStore.cpp

@@ -297,10 +297,6 @@ FileStore::FileStore(std::string path, int numWorkers)
   addHelper(refCountKey_, 1);
 }
 
-c10::intrusive_ptr<Store> FileStore::clone() {
-  return c10::make_intrusive<FileStore>(path_, numWorkers_);
-}
-
 // NOLINTNEXTLINE(bugprone-exception-escape)
 FileStore::~FileStore() {
   // If the file does not exist - exit.

torch/csrc/distributed/c10d/FileStore.hpp

@@ -13,8 +13,6 @@ class TORCH_API FileStore : public Store {
  public:
   explicit FileStore(std::string path, int numWorkers);
 
-  c10::intrusive_ptr<Store> clone() override;
-
   ~FileStore() override;
 
   void set(const std::string& key, const std::vector<uint8_t>& value) override;

torch/csrc/distributed/c10d/HashStore.cpp

@@ -9,10 +9,6 @@
 
 namespace c10d {
 
-c10::intrusive_ptr<Store> HashStore::clone() {
-  return c10::intrusive_ptr<Store>::unsafe_reclaim_from_nonowning(this);
-}
-
 void HashStore::set(const std::string& key, const std::vector<uint8_t>& data) {
   std::unique_lock<std::mutex> lock(m_);
   map_[key] = data;

torch/csrc/distributed/c10d/HashStore.hpp

@@ -10,8 +10,6 @@ namespace c10d {
 
 class TORCH_API HashStore : public Store {
  public:
-  c10::intrusive_ptr<Store> clone() override;
-
   ~HashStore() override = default;
 
   void set(const std::string& key, const std::vector<uint8_t>& data) override;

torch/csrc/distributed/c10d/PrefixStore.cpp

@@ -6,10 +6,6 @@ namespace c10d {
 PrefixStore::PrefixStore(std::string prefix, c10::intrusive_ptr<Store> store)
     : prefix_(std::move(prefix)), store_(std::move(store)) {}
 
-c10::intrusive_ptr<Store> PrefixStore::clone() {
-  return c10::make_intrusive<PrefixStore>(prefix_, store_->clone());
-}
-
 std::string PrefixStore::joinKey(const std::string& key) {
   return prefix_ + "/" + key;
 }

torch/csrc/distributed/c10d/PrefixStore.hpp

@@ -8,8 +8,6 @@ class TORCH_API PrefixStore : public Store {
  public:
   explicit PrefixStore(std::string prefix, c10::intrusive_ptr<Store> store);
 
-  c10::intrusive_ptr<Store> clone() override;
-
   using Store::set;
   void set(const std::string& key, const std::vector<uint8_t>& value) override;
 

torch/csrc/distributed/c10d/Store.hpp

@@ -32,10 +32,6 @@ class TORCH_API Store : public torch::CustomClassHolder {
 
   ~Store() override = default;
 
-  // Clone a thread safe copy of this store object that points to the same
-  // underlying store.
-  virtual c10::intrusive_ptr<Store> clone() = 0;
-
   void set(const std::string& key, const std::string& value);
 
   virtual void set(

torch/csrc/distributed/c10d/TCPStore.cpp

@@ -350,17 +350,6 @@ TCPStore::TCPStore(std::string host, const TCPStoreOptions& opts)
 
 TCPStore::~TCPStore() = default;
 
-c10::intrusive_ptr<Store> TCPStore::clone() {
-  TCPStoreOptions opts;
-  opts.port = addr_.port;
-  opts.isServer = false;
-  opts.waitWorkers = false;
-  opts.timeout = timeout_;
-  opts.useLibUV = usingLibUv_;
-
-  return c10::make_intrusive<TCPStore>(addr_.host, opts);
-}
-
 void TCPStore::waitForWorkers() {
   STATIC_SCOPED_WAIT_COUNTER(pytorch.wait_counter.TCPStore__waitForWorkers);
   if (!numWorkers_.has_value()) {

torch/csrc/distributed/c10d/TCPStore.hpp

@@ -77,8 +77,6 @@ class TORCH_API TCPStore : public Store {
 
   ~TCPStore() override;
 
-  c10::intrusive_ptr<Store> clone() override;
-
   void set(const std::string& key, const std::vector<uint8_t>& value) override;
 
   std::vector<uint8_t> compareSet(

torch/csrc/distributed/c10d/init.cpp

@@ -274,10 +274,6 @@ class PythonStore : public ::c10d::Store {
     PYBIND11_OVERLOAD_PURE(void, ::c10d::Store, wait, keys, timeout);
   }
 
-  c10::intrusive_ptr<Store> clone() override {
-    PYBIND11_OVERLOAD_PURE(c10::intrusive_ptr<Store>, ::c10d::Store, clone);
-  }
-
   // Note: this function manually calls the Python-side overload
   // for this function instead of using the PYBIND11_OVERLOAD_XYZ
   // macros. This is done so that we can call the Python-side
@@ -1212,16 +1208,6 @@ and :class:`~torch.distributed.HashStore`).
 )")
           // Default constructor.
           .def(py::init<>())
-          .def(
-              "clone",
-              &::c10d::Store::clone,
-              py::call_guard<py::gil_scoped_release>(),
-              R"(
-Clones the store and returns a new object that points to the same underlying
-store. The returned store can be used concurrently with the original object.
-This is intended to provide a safe way to use a store from multiple threads by
-cloning one store per thread.
-)")
           // Convert from std::string to std::vector<uint8>.
           .def(
               "set",
@@ -3572,14 +3558,6 @@ such as `dist.all_reduce(tensor, async_op=True)`.
         if (get("key3") != "15") {
           TORCH_CHECK(false, "assertion failed");
         }
-
-        auto cloned = store->clone();
-        store->set("foo", "bar");
-
-        auto ret = cloned->get("foo");
-        TORCH_CHECK(
-            std::string(ret.begin(), ret.end()) == "bar",
-            "checked clone behavior");
       },
       py::call_guard<py::gil_scoped_release>());