Revert "[BE] Reroute all uses of proxy_tensor.maybe_disable_fake_tensor_mode to fake_tensor.unset_fake_temporarily (#132770)"

This reverts commit 902c6f3a191fb2ecb1976895b3e9eaae4b257b89.

Reverted https://github.com/pytorch/pytorch/pull/132770 on behalf of https://github.com/ezyang due to Removed API was recommitted ([comment](https://github.com/pytorch/pytorch/pull/132770#issuecomment-2275749689))

docs/source/conf.py

@@ -850,6 +850,7 @@ coverage_ignore_functions = [
     "get_torch_dispatch_modes",
     "has_proxy_slot",
     "is_sym_node",
+    "maybe_disable_fake_tensor_mode",
     "maybe_handle_decomp",
     "proxy_call",
     "set_meta",

docs/source/torch.compiler_fake_tensor.rst

@@ -85,8 +85,8 @@ Other useful stuff:
 
 .. code:: python
 
-    from torch._subclasses.fake_tensor import unset_fake_temporarily
-    with unset_fake_temporarily():
+    from torch.fx.experimental.proxy_tensor import maybe_disable_fake_tensor_mode
+    with maybe_disable_fake_tensor_mode():
         # fake mode is disabled here, you can do real tensor compute
 
 When might you want to disable fake tensor mode? Usually you don't want to do this. One niche case where we've found it useful is to implement constant propagation on fake tensors: in this case, we need to do some actual tensor computation even though we're in a fake tensor mode.

test/allowlist_for_publicAPI.json

@@ -1926,6 +1926,7 @@
     "get_torch_dispatch_modes",
     "has_proxy_slot",
     "is_sym_node",
+    "maybe_disable_fake_tensor_mode",
     "maybe_handle_decomp",
     "proxy_call",
     "set_meta",

torch/_dynamo/eval_frame.py

@@ -53,11 +53,10 @@ from torch._C._dynamo.eval_frame import (  # noqa: F401
     unsupported,
 )
 from torch._dispatch.python import enable_python_dispatcher
-from torch._subclasses.fake_tensor import unset_fake_temporarily
 from torch._utils_internal import justknobs_check, log_export_usage
 from torch.export.dynamic_shapes import _process_dynamic_shapes
 from torch.fx import GraphModule
-from torch.fx.experimental.proxy_tensor import make_fx
+from torch.fx.experimental.proxy_tensor import make_fx, maybe_disable_fake_tensor_mode
 from torch.fx.experimental.symbolic_shapes import (
     ConstraintViolationError,
     DimDynamic,
@@ -1535,7 +1534,9 @@ def export(
                 with torch.fx.traceback.preserve_node_meta():
                     return torch.fx.Interpreter(graph).run(*args)
 
-            with unset_fake_temporarily(), enable_python_dispatcher(), fake_mode:
+            with maybe_disable_fake_tensor_mode(), enable_python_dispatcher(), (
+                fake_mode
+            ):
                 try:
                     graph = make_fx(
                         graph_with_interpreter,

torch/_export/__init__.py

@@ -40,8 +40,7 @@ from torch.export.graph_signature import (
 )
 from torch.fx import traceback as fx_traceback
 from torch.fx._compatibility import compatibility
-from torch.fx.experimental.proxy_tensor import make_fx
-from torch._subclasses.fake_tensor import unset_fake_temporarily
+from torch.fx.experimental.proxy_tensor import make_fx, maybe_disable_fake_tensor_mode
 from torch.fx.graph import _PyTreeCodeGen, _PyTreeInfo
 
 from .wrappers import _wrap_submodules

torch/_inductor/pattern_matcher.py

@@ -80,8 +80,7 @@ from torch._dispatch.python import enable_python_dispatcher
 from torch._dynamo.utils import counters
 from torch._inductor.config import trace as trace_config
 from torch._prims_common import is_integer_dtype
-from torch._subclasses.fake_tensor import unset_fake_temporarily
-from torch.fx.experimental.proxy_tensor import make_fx
+from torch.fx.experimental.proxy_tensor import make_fx, maybe_disable_fake_tensor_mode
 from torch.fx.experimental.symbolic_shapes import guard_size_oblivious
 from torch.fx.immutable_collections import immutable_dict, immutable_list
 from torch.fx.passes.graph_transform_observer import GraphTransformObserver
@@ -1929,7 +1928,9 @@ def init_once_fakemode(fn: Callable[..., Any]) -> Callable[[], Any]:
     def lazy_init() -> Any:
         counters_ref = counters["inductor"].copy()
 
-        with torch._guards.tracing(None), unset_fake_temporarily(), FakeTensorMode():
+        with torch._guards.tracing(
+            None
+        ), maybe_disable_fake_tensor_mode(), FakeTensorMode():
             result = fn()
 
         # clear view matches encountered during tracing

torch/export/exported_program.py

@@ -41,11 +41,11 @@ if TYPE_CHECKING:
 import torch
 import torch.utils._pytree as pytree
 from torch._export.verifier import Verifier
-from torch._subclasses.fake_tensor import unset_fake_temporarily
 from torch._subclasses.functional_tensor import FunctionalTensor
 from torch.export._tree_utils import is_equivalent, reorder_kwargs
 from torch.fx._compatibility import compatibility
 from torch.fx._utils import first_call_function_nn_module_stack
+from torch.fx.experimental.proxy_tensor import maybe_disable_fake_tensor_mode
 from torch.fx.passes.infra.pass_base import PassResult
 from torch.fx.passes.infra.pass_manager import PassManager
 from torch.fx.passes.runtime_assert import insert_deferred_runtime_asserts
@@ -92,7 +92,7 @@ class ModuleCallEntry:
 def _disable_prexisiting_fake_mode(fn):
     @functools.wraps(fn)
     def wrapper(*args, **kwargs):
-        with unset_fake_temporarily():
+        with maybe_disable_fake_tensor_mode():
             return fn(*args, **kwargs)
 
     return wrapper

torch/fx/experimental/proxy_tensor.py

@@ -17,7 +17,7 @@ import typing_extensions
 import warnings
 import weakref
 from collections import defaultdict
-from contextlib import contextmanager, ExitStack, nullcontext
+from contextlib import AbstractContextManager, contextmanager, ExitStack, nullcontext
 from dataclasses import dataclass
 from typing import (
     Any,
@@ -660,6 +660,12 @@ def track_tensor_tree(
     return inner_res
 
 
+def maybe_disable_fake_tensor_mode() -> AbstractContextManager:
+    # TODO: figure out if this API generally makes sense and bake it into the
+    # library
+    return unset_fake_temporarily()
+
+
 @dataclass
 class _ProxyTensor:
     proxy: Proxy
@@ -818,7 +824,7 @@ def proxy_call(
             const_args, const_kwargs = pytree.tree_unflatten(
                 const_flat_args_kwargs, spec
             )
-            with unset_fake_temporarily():
+            with maybe_disable_fake_tensor_mode():
                 return func(*const_args, **const_kwargs)
         # If any of the Tensor inputs are "real" (not FakeTensor), we may
         # incorrectly burn in constants by allowing this access.  Raise
@@ -945,7 +951,7 @@ def proxy_call(
         func is torch.ops.aten.lift_fresh_copy.default
         and out.numel() <= CONSTANT_NUMEL_LIMIT
     ):
-        with unset_fake_temporarily():
+        with maybe_disable_fake_tensor_mode():
             assert isinstance(args[0], (Proxy, Tensor)), type(args[0])
             constant = args[0].clone()
     elif (
@@ -955,7 +961,7 @@ def proxy_call(
         and pytree.tree_all_only(Tensor, tensor_numel_in_limit, out)
     ):
         # NB: do NOT include factories as constants
-        with unset_fake_temporarily():
+        with maybe_disable_fake_tensor_mode():
             const_flat_args_kwargs = [
                 t.constant if isinstance(t, _ProxyTensor) else t
                 for t in f_flat_args_kwargs

torch/onnx/_internal/fx/_pass.py

@@ -12,7 +12,7 @@ from typing import Any, Callable, TYPE_CHECKING
 
 import torch
 import torch.fx
-from torch._subclasses.fake_tensor import unset_fake_temporarily
+from torch.fx.experimental.proxy_tensor import maybe_disable_fake_tensor_mode
 from torch.onnx._internal.fx import diagnostics, onnxfunction_dispatcher
 
 
@@ -220,7 +220,7 @@ class Transform(abc.ABC):
         Scan through all nodes in graph and their meta['val'] to detect fake mode.
         """
         fake_tensors = [node.meta.get("val") for node in self.module.graph.nodes]
-        with unset_fake_temporarily():
+        with maybe_disable_fake_tensor_mode():
             return torch._dynamo.utils.detect_fake_mode(fake_tensors)
 
     def _maybe_fakefy_args(

torch/onnx/_internal/fx/passes/decomp.py

@@ -7,7 +7,6 @@ from typing import Callable, Mapping, TYPE_CHECKING
 import torch
 import torch._ops
 from torch._dispatch import python as python_dispatch
-from torch._subclasses import fake_tensor
 from torch.fx.experimental import proxy_tensor
 from torch.onnx._internal.fx import _pass, diagnostics
 from torch.onnx._internal.fx.passes import _utils
@@ -15,6 +14,7 @@ from torch.onnx._internal.fx.passes import _utils
 
 if TYPE_CHECKING:
     import torch.fx
+    from torch._subclasses import fake_tensor
 
 
 class Decompose(_pass.Transform):
@@ -66,7 +66,7 @@ class Decompose(_pass.Transform):
 
         # Apply decomposition table to the input graph.
         assert fake_mode is not None  # for mypy
-        with fake_tensor.unset_fake_temporarily(), python_dispatch.enable_python_dispatcher(), (
+        with proxy_tensor.maybe_disable_fake_tensor_mode(), python_dispatch.enable_python_dispatcher(), (
             fake_mode
         ):
             decomposed_module = proxy_tensor.make_fx(

torch/onnx/_internal/fx/passes/functionalization.py

@@ -2,19 +2,22 @@
 from __future__ import annotations
 
 import contextlib
-from typing import Callable
+from typing import Callable, TYPE_CHECKING
 
 import torch
 import torch._ops
 import torch.func
 import torch.fx
-from torch._subclasses import fake_tensor
 from torch.fx.experimental import proxy_tensor
 from torch.onnx._internal.fx import _pass, diagnostics
 from torch.onnx._internal.fx.passes import _utils
 from torch.utils import _pytree as pytree
 
 
+if TYPE_CHECKING:
+    from torch._subclasses import fake_tensor
+
+
 class Functionalize(_pass.Transform):
     """Functionalize a GraphModule.
 
@@ -116,7 +119,7 @@ class Functionalize(_pass.Transform):
             tracing_mode = "symbolic" if self.enable_dynamic_axes else "fake"
 
         assert fake_mode is not None  # for mypy
-        with fake_tensor.unset_fake_temporarily(), fake_mode:
+        with proxy_tensor.maybe_disable_fake_tensor_mode(), fake_mode:
             graph_module = proxy_tensor.make_fx(
                 functionalized_callable,
                 decomposition_table={},

torch/onnx/_internal/fx/passes/type_promotion.py

@@ -19,7 +19,6 @@ from torch._prims_common import (
 )
 from torch._refs import linalg as _linalg_refs, nn as _nn_refs, special as _special_refs
 from torch._refs.nn import functional as _functional_refs
-from torch._subclasses import fake_tensor
 from torch.fx.experimental import proxy_tensor
 from torch.onnx._internal.fx import _pass, diagnostics, type_utils as fx_type_utils
 from torch.utils import _python_dispatch, _pytree
@@ -28,6 +27,8 @@ from torch.utils import _python_dispatch, _pytree
 if TYPE_CHECKING:
     from types import ModuleType
 
+    from torch._subclasses import fake_tensor
+
 
 logger = logging.getLogger(__name__)
 
@@ -1715,7 +1716,7 @@ class InsertTypePromotion(_pass.Transform):
         fake_mode = self.fake_mode
         assert fake_mode is not None, "Cannot detect fake_mode."
 
-        with fake_tensor.unset_fake_temporarily(), (
+        with proxy_tensor.maybe_disable_fake_tensor_mode(), (
             fake_mode
         ), fx_traceback.preserve_node_meta():
             self.interpreter.run(*fake_args)