[Dynamo] Guard serialization for CLOSURE_MATCH (pytorch#152728)

Unsupported because it uses unsupported FUNCTION_MATCH.

Pull Request resolved: pytorch#152728
Approved by: https://github.com/jansel
ghstack dependencies: pytorch#152725, pytorch#152727

Author: jbschlosser

test/dynamo/test_guard_serialization.py

@@ -38,6 +38,10 @@ def forward(self, x):
         return x + 1
 
 
+def global_func(x):
+    return x + 1
+
+
 class SubclassWithMeta(torch.Tensor):
     @staticmethod
     def __new__(cls, a, extra, outer_size=None, outer_stride=None):
@@ -637,6 +641,20 @@ def fn(x):
         ):
             self._test_serialization("FUNCTION_MATCH", fn, x)
 
+    def test_closure_match(self):
+        def fn(x):
+            # usage of this global function installs a CLOSURE_MATCH guard
+            return global_func(x)
+
+        x = torch.randn(3)
+
+        # we don't support CLOSURE_MATCH because it adds a FUNCTION_MATCH guard, and we don't
+        # support that in serialization
+        with self.assertRaisesRegex(
+            RuntimeError, "CLOSURE_MATCH guard cannot be serialized."
+        ):
+            self._test_serialization("CLOSURE_MATCH", fn, x)
+
     def test_dict_version(self):
         def fn(x):
             return pytree.tree_leaves(x)[0] + 1

torch/_dynamo/guards.py

@@ -1768,6 +1768,9 @@ def FUNCTION_MATCH(self, guard: Guard):
 
     def CLOSURE_MATCH(self, guard: Guard):
         """matches a closure by __code__ id."""
+        # don't support this in serialization because it uses unsupported FUNCTION_MATCH
+        if self.serialization_mode == "save":
+            raise RuntimeError("CLOSURE_MATCH guard cannot be serialized.")
         val = self.get(guard.name)
         # Strictly only want user-defined functions
         if type(val) == types.FunctionType and hasattr(val, "__code__"):