[export] Remove CallSpec (pytorch#117671)

Summary:

X-link: pytorch/executorch#1618

This is not really being used anywhere

Test Plan: CI

Reviewed By: zhxchen17

Differential Revision: D52842563

torch/_export/__init__.py

@@ -73,9 +73,6 @@
 from torch.fx.graph import _PyTreeCodeGen, _PyTreeInfo
 from torch.utils._sympy.value_ranges import ValueRangeError, ValueRanges
 
-from .exported_program import (
-    CallSpec,
-)
 from .passes.add_runtime_assertions_for_constraints_pass import (
     _AddRuntimeAssertionsForInlineConstraintsPass,
 )

torch/_export/exported_program.py

@@ -1,11 +1,8 @@
-import dataclasses
-from typing import Optional
 import warnings
 
 
 import torch
 import torch.fx
-import torch.utils._pytree as pytree
 
 
 # TODO(ycao): This is added to avoid breaking existing code temporarily.
@@ -32,13 +29,6 @@
 ]
 
 
-# Information to maintain user calling/returning specs
-@dataclasses.dataclass
-class CallSpec:
-    in_spec: Optional[pytree.TreeSpec]
-    out_spec: Optional[pytree.TreeSpec]
-
-
 def _create_graph_module_for_export(root, graph):
     try:
         gm = torch.fx.GraphModule(root, graph)

torch/export/exported_program.py

@@ -1,4 +1,5 @@
 import copy
+from collections import namedtuple
 import dataclasses
 import functools
 import types
@@ -213,7 +214,7 @@ def example_inputs(self):
     @property
     @compatibility(is_backward_compatible=False)
     def call_spec(self):
-        from torch._export.exported_program import CallSpec
+        CallSpec = namedtuple("CallSpec", ["in_spec", "out_spec"])
 
         if len(self.module_call_graph) == 0:
             return CallSpec(in_spec=None, out_spec=None)