Use Python properties to cleanly apply rules to checkpoints

captum/influence/_core/tracincp.py

@@ -140,16 +140,9 @@ def __init__(
                     Default: None
         """
 
-        self.model = model
+        self.model: Module = model
 
-        if isinstance(checkpoints, str):
-            self.checkpoints = AV.sort_files(glob.glob(join(checkpoints, "*")))
-        elif isinstance(checkpoints, List) and isinstance(checkpoints[0], str):
-            self.checkpoints = AV.sort_files(checkpoints)
-        else:
-            self.checkpoints = list(checkpoints)  # cast to avoid mypy error
-        if isinstance(self.checkpoints, List):
-            assert len(self.checkpoints) > 0, "No checkpoints saved!"
+        self.checkpoints = checkpoints  # type: ignore
 
         self.checkpoints_load_func = checkpoints_load_func
         self.loss_fn = loss_fn
@@ -181,6 +174,24 @@ def __init__(
                 "percentage completion of the computation, nor any time estimates."
             )
 
+    @property
+    def checkpoints(self) -> List[str]:
+        return self._checkpoints
+
+    @checkpoints.setter
+    def checkpoints(self, checkpoints: Union[str, List[str], Iterator]) -> None:
+        if isinstance(checkpoints, str):
+            self._checkpoints = AV.sort_files(glob.glob(join(checkpoints, "*")))
+        elif isinstance(checkpoints, List) and isinstance(checkpoints[0], str):
+            self._checkpoints = AV.sort_files(checkpoints)
+        else:
+            self._checkpoints = list(checkpoints)  # cast to avoid mypy error
+
+        if len(self._checkpoints) <= 0:
+            raise ValueError(
+                f"Invalid checkpoints provided for TracIn class: {checkpoints}!"
+            )
+
     @abstractmethod
     def self_influence(
         self,

captum/influence/_core/tracincp_fast_rand_proj.py

@@ -82,7 +82,7 @@ class TracInCPFast(TracInCPBase):
     def __init__(
         self,
         model: Module,
-        final_fc_layer: Module,
+        final_fc_layer: Union[Module, str],
         train_dataset: Union[Dataset, DataLoader],
         checkpoints: Union[str, List[str], Iterator],
         checkpoints_load_func: Callable = _load_flexible_state_dict,
@@ -183,7 +183,7 @@ def __init__(
         self.vectorize = vectorize
 
         # TODO: restore prior state
-        self.final_fc_layer = final_fc_layer
+        self.final_fc_layer = final_fc_layer  # type: ignore
         for param in self.final_fc_layer.parameters():
             param.requires_grad = True
 

tests/influence/_core/test_tracin_validation.py

@@ -36,7 +36,7 @@ class TestTracinValidator(BaseTest):
     )
     def test_tracin_require_inputs_dataset(
         self,
-        reduction,
+        reduction: str,
         tracin_constructor: Callable,
     ) -> None:
         """
@@ -64,6 +64,10 @@ def test_tracin_require_inputs_dataset(
                 tracin.influence(None, k=None)
 
     def test_tracincp_fast_rand_proj_inputs(self) -> None:
+        """
+        This test verifies that TracInCPFast should be initialized
+        with a valid `final_fc_layer`.
+        """
         with tempfile.TemporaryDirectory() as tmpdir:
             (
                 net,
@@ -83,3 +87,34 @@ def test_tracincp_fast_rand_proj_inputs(self) -> None:
                     loss_fn=nn.MSELoss(),
                     batch_size=1,
                 )
+
+    @parameterized.expand(
+        param_list,
+        name_func=build_test_name_func(),
+    )
+    def test_tracincp_input_checkpoints(
+        self, reduction: str, tracin_constructor: Callable
+    ) -> None:
+        """
+        This test verifies that tracinCP and tracinCPFast
+        class should be initialized with valid `checkpoints`.
+        """
+        with tempfile.TemporaryDirectory() as invalid_tmpdir:
+            with tempfile.TemporaryDirectory() as tmpdir:
+                (
+                    net,
+                    train_dataset,
+                    test_samples,
+                    test_labels,
+                ) = get_random_model_and_data(tmpdir, unpack_inputs=False)
+
+            with self.assertRaisesRegex(
+                ValueError, "Invalid checkpoints provided for TracIn class: "
+            ):
+                tracin_constructor(
+                    net,
+                    train_dataset,
+                    invalid_tmpdir,
+                    loss_fn=nn.MSELoss(),
+                    batch_size=1,
+                )