move out version converter logic from sequential

Author: titaiwangms

onnxscript/version_converter/__init__.py

@@ -37,18 +37,26 @@ def __init__(self, target_version: int, fallback: bool = False) -> None:
         super().__init__()
         self.target_version = target_version
         self.fallback = fallback
-        self.convert_pass = ir.passes.Sequential(
-            _ConvertVersionPass(
-                target_version=target_version,
-                fallback=fallback,
-            ),
+        self._convert_pass = _ConvertVersionPass(
+            target_version=target_version,
+            fallback=fallback,
+        )
+        self._cleanup_passes = ir.passes.Sequential(
             common_passes.RemoveUnusedNodesPass(),
             common_passes.RemoveUnusedFunctionsPass(),
             common_passes.RemoveUnusedOpsetsPass(),
         )
 
     def call(self, model: ir.Model) -> ir.passes.PassResult:
-        return self.convert_pass(model)
+        # Run the conversion pass outside of Sequential so that errors
+        # (e.g. VersionConverterError) propagate directly without being
+        # wrapped in PassError.
+        result = self._convert_pass(model)
+        cleanup_result = self._cleanup_passes(result)
+        return ir.passes.PassResult(
+            cleanup_result.model,
+            result.modified or cleanup_result.modified,
+        )
 
 
 class _ConvertVersionPass(ir.passes.InPlacePass):

onnxscript/version_converter/_version_converter_test.py

@@ -507,19 +507,12 @@ def test_version_convert_raises_on_function_node_with_ref_attribute(self):
 
         target_version = 20
         with self.assertRaises(
-            (
-                version_converter._version_converter.VersionConverterError,  # pylint: disable=protected-access
-                ir.passes.PassError,
-            )
+            version_converter._version_converter.VersionConverterError,  # pylint: disable=protected-access
         ) as ctx:
             version_converter.convert_version(model, target_version=target_version)
-        # Check the error message, unwrapping PassError if needed
-        error = ctx.exception
-        if isinstance(error, ir.passes.PassError) and error.__cause__ is not None:
-            error = error.__cause__
-        self.assertIn(
+        self.assertRegex(
+            str(ctx.exception),
             "has ref attribute, which is not supported by version converter",
-            str(error),
         )