handle edge case

Author: awaelchli

src/lightning/pytorch/utilities/model_summary/model_summary.py

@@ -343,6 +343,7 @@ def _add_leftover_params_to_summary(self, arrays: List[Tuple[str, List[str]]], t
         layer_summaries["Name"].append(LEFTOVER_PARAMS_NAME)
         layer_summaries["Type"].append(NOT_APPLICABLE)
         layer_summaries["Params"].append(get_human_readable_count(total_leftover_params))
+        layer_summaries["Mode"].append(NOT_APPLICABLE)
         if "In sizes" in layer_summaries:
             layer_summaries["In sizes"].append(NOT_APPLICABLE)
         if "Out sizes" in layer_summaries:

tests/tests_pytorch/utilities/test_model_summary.py

@@ -443,10 +443,16 @@ def test_summary_training_mode():
     assert summary_data["Mode"] == [
         "train",  # branch1
         "eval",   # branch2
-        "train"   # head
+        "train",  # head
     ]
 
     summary = summarize(model, max_depth=-1)
     expected_eval = {"branch1.1.0", "branch2"}
     for name, layer_summary in summary._layer_summary.items():
         assert (name in expected_eval) == (not layer_summary.training)
+
+    # A model with params not belonging to a layer
+    model = NonLayerParamsModel()
+    model.layer.eval()
+    summary_data = OrderedDict(summarize(model)._get_summary_data())
+    assert summary_data["Mode"] == ["eval", "n/a"]