[Fix] [torch.compile] Improve UUID system for custom passes (#15249)

Signed-off-by: luka <luka@neuralmagic.com>

tests/compile/test_pass_manager.py

@@ -1,6 +1,5 @@
 # SPDX-License-Identifier: Apache-2.0
-
-import pickle
+import copy
 
 import pytest
 import torch
@@ -10,32 +9,63 @@ from vllm.compilation.pass_manager import PostGradPassManager
 from vllm.config import CompilationConfig
 
 
+# dummy custom pass that doesn't inherit
 def simple_callable(graph: torch.fx.Graph):
     pass
 
 
-callable_uuid = CallableInductorPass(simple_callable,
-                                     InductorPass.hash_source(__file__))
-
-
-@pytest.mark.parametrize(
-    "works, callable",
-    [
-        (False, simple_callable),
-        (True, callable_uuid),
-        (True, CallableInductorPass(simple_callable)),
-    ],
-)
-def test_pass_manager(works: bool, callable):
+# Should fail to add directly to the pass manager
+def test_bad_callable():
     config = CompilationConfig().pass_config
 
     pass_manager = PostGradPassManager()
     pass_manager.configure(config)
 
-    # Try to add the callable to the pass manager
-    if works:
-        pass_manager.add(callable)
-        pickle.dumps(pass_manager)
-    else:
-        with pytest.raises(AssertionError):
-            pass_manager.add(callable)
+    with pytest.raises(AssertionError):
+        pass_manager.add(simple_callable)  # noqa, type wrong on purpose
+
+
+# Pass that inherits from InductorPass
+class ProperPass(InductorPass):
+
+    def __call__(self, graph: torch.fx.graph.Graph) -> None:
+        pass
+
+
+@pytest.mark.parametrize(
+    "callable",
+    [
+        ProperPass(),
+        # Can also wrap callables in CallableInductorPass for compliance
+        CallableInductorPass(simple_callable),
+        CallableInductorPass(simple_callable,
+                             InductorPass.hash_source(__file__))
+    ],
+)
+def test_pass_manager_uuid(callable):
+    config = CompilationConfig().pass_config
+
+    pass_manager = PostGradPassManager()
+    pass_manager.configure(config)
+
+    # Check that UUID is different if the same pass is added 2x
+    pass_manager.add(callable)
+    uuid1 = pass_manager.uuid()
+    pass_manager.add(callable)
+    uuid2 = pass_manager.uuid()
+    assert uuid1 != uuid2
+
+    # UUID should be the same as the original one,
+    # as we constructed in the same way.
+    pass_manager2 = PostGradPassManager()
+    pass_manager2.configure(config)
+    pass_manager2.add(callable)
+    assert uuid1 == pass_manager2.uuid()
+
+    # UUID should be different due to config change
+    config2 = copy.deepcopy(config)
+    config2.enable_fusion = not config2.enable_fusion
+    pass_manager3 = PostGradPassManager()
+    pass_manager3.configure(config2)
+    pass_manager3.add(callable)
+    assert uuid1 != pass_manager3.uuid()