clean up error_on_nested_jit_trace flag (pytorch#136961)

Pull Request resolved: pytorch#136961
Approved by: https://github.com/jansel

Author: bobrenjc93

test/dynamo/test_repros.py

@@ -3704,9 +3704,6 @@ def f(x):
         with self.assertRaises(RuntimeError):
             torch.jit.trace(f, torch.randn(3))
 
-        with torch._dynamo.config.patch(error_on_nested_jit_trace=False):
-            torch.jit.trace(f, torch.randn(3))
-
     @torch._dynamo.config.patch("assume_static_by_default", False)
     def test_tensor_split(self):
         def f(x):

torch/_dynamo/config.py

@@ -334,8 +334,7 @@ def _get_optimize_ddp_mode():
 # If True, raise when aot autograd is unsafe to use
 raise_on_unsafe_aot_autograd = False
 
-# If true, error if you torch.jit.trace over a dynamo-optimized function.
-# If false, silently suppress dynamo
+# This flag is ignored and maintained for backwards compatibility.
 error_on_nested_jit_trace = True
 
 # If true, error with a better message if we symbolically trace over a

torch/_dynamo/eval_frame.py

@@ -440,13 +440,10 @@ def _fn(*args, **kwargs):
                     return fn(*args, **kwargs)
 
             if is_jit_tracing():
-                if config.error_on_nested_jit_trace:
-                    raise RuntimeError(
-                        "Detected that you are using FX to torch.jit.trace "
-                        "a dynamo-optimized function. This is not supported at the moment."
-                    )
-                else:
-                    return fn(*args, **kwargs)
+                raise RuntimeError(
+                    "Detected that you are using FX to torch.jit.trace "
+                    "a dynamo-optimized function. This is not supported at the moment."
+                )
 
             cleanups = [enter() for enter in self.enter_exit_hooks]
             prior = _maybe_set_eval_frame(callback)