Add pass name to error message

Author: aborgna-q

hugr-py/src/hugr/passes/_composable_pass.py

@@ -44,6 +44,7 @@ def then(self, other: ComposablePass) -> ComposablePass:
 
 
 def impl_pass_run(
+    pass_: ComposablePass,
     *,
     hugr: Hugr,
     inplace: bool,
@@ -55,6 +56,7 @@ def impl_pass_run(
 
     At least one of the `inplace_call` or `copy_call` arguments must be provided.
 
+    :param pass_: The pass being run. Used for error messages.
     :param hugr: The Hugr to apply the pass to.
     :param inplace: Whether to apply the pass inplace.
     :param inplace_call: The method to apply the pass inplace.
@@ -79,7 +81,7 @@ def impl_pass_run(
         pass_result.original_dirty = False
         return pass_result
     else:
-        msg = "Pass must implement at least an inplace or copy run method"
+        msg = f"{pass_.name} needs to implement at least an inplace or copy run method"
         raise ValueError(msg)
 
 
@@ -106,6 +108,7 @@ def apply(hugr: Hugr) -> PassResult:
             return pass_result
 
         return impl_pass_run(
+            self,
             hugr=hugr,
             inplace=inplace,
             inplace_call=apply,

hugr-py/tests/test_passes.py

@@ -1,5 +1,7 @@
 from copy import deepcopy
 
+import pytest
+
 from hugr.hugr.base import Hugr
 from hugr.passes._composable_pass import (
     ComposablePass,
@@ -13,6 +15,7 @@ def test_composable_pass() -> None:
     class MyDummyInlinePass(ComposablePass):
         def run(self, hugr: Hugr, inplace: bool = True) -> PassResult:
             return impl_pass_run(
+                self,
                 hugr=hugr,
                 inplace=inplace,
                 inplace_call=lambda hugr: PassResult.for_pass(
@@ -28,6 +31,7 @@ def run(self, hugr: Hugr, inplace: bool = True) -> PassResult:
     class MyDummyCopyPass(ComposablePass):
         def run(self, hugr: Hugr, inplace: bool = True) -> PassResult:
             return impl_pass_run(
+                self,
                 hugr=hugr,
                 inplace=inplace,
                 copy_call=lambda hugr: PassResult.for_pass(
@@ -82,3 +86,20 @@ def run(self, hugr: Hugr, inplace: bool = True) -> PassResult:
         ("MyDummyCopyPass", None),
     ]
     assert copy_result.hugr is not hugr
+
+
+def test_invalid_composable_pass() -> None:
+    class MyDummyInvalidPass(ComposablePass):
+        def run(self, hugr: Hugr, inplace: bool = True) -> PassResult:
+            return impl_pass_run(
+                self,
+                hugr=hugr,
+                inplace=inplace,
+            )
+
+    dummy_invalid = MyDummyInvalidPass()
+    with pytest.raises(
+        ValueError,
+        match="MyDummyInvalidPass needs to implement at least an inplace or copy run method",  # noqa: E501
+    ):
+        dummy_invalid.run(Hugr())