Fix unserializable parameters value

RELEASE.md

@@ -12,6 +12,9 @@
 
 - Update Kedro-Viz telemetry for opt-out model (#2022)
 
+## Bug fixes and other changes
+
+- Fix unserializable parameters value (#2122)
 
 # Release 10.0.0
 

package/kedro_viz/data_access/repositories/catalog.py

@@ -131,7 +131,7 @@ def get_dataset(self, dataset_name: str) -> Optional["AbstractDataset"]:
             else:  # pragma: no cover
                 dataset_obj = self._catalog._get_dataset(dataset_name)
         except DatasetNotFoundError:
-            dataset_obj = MemoryDataset()  # pylint: disable=abstract-class-instantiated
+            dataset_obj = MemoryDataset()
 
         return dataset_obj
 

package/kedro_viz/models/flowchart.py

@@ -9,6 +9,7 @@
 from types import FunctionType
 from typing import Any, ClassVar, Dict, List, Optional, Set, Union, cast
 
+from fastapi.encoders import jsonable_encoder
 from kedro.pipeline.node import Node as KedroNode
 from pydantic import (
     BaseModel,
@@ -861,7 +862,13 @@ def parameter_value(self) -> Any:
             return None
 
         try:
-            return self.kedro_obj.load()
+            actual_parameter_value = self.kedro_obj.load()
+            # Return only json serializable value
+            return jsonable_encoder(actual_parameter_value)
+        except (TypeError, ValueError, RecursionError):
+            # In case the parameter is not JSON serializable,
+            # return the string representation
+            return str(actual_parameter_value)
         except (AttributeError, DatasetError):
             # This except clause triggers if the user passes a parameter that is not
             # defined in the catalog (DatasetError) it also catches any case where
@@ -870,6 +877,14 @@ def parameter_value(self) -> Any:
                 "Cannot find parameter `%s` in the catalog.", self.parameter_name
             )
             return None
+        # pylint: disable=broad-exception-caught
+        except Exception as exc:  # pragma: no cover
+            logger.error(
+                "An error occurred when loading parameter `%s` in the catalog :: %s",
+                self.parameter_name,
+                exc,
+            )
+            return None
 
 
 class ParametersNodeMetadata(GraphNodeMetadata):

package/kedro_viz/models/utils.py

@@ -1,4 +1,5 @@
 """`kedro_viz.models.utils` contains utility functions used in the `kedro_viz.models` package"""
+
 import logging
 from typing import TYPE_CHECKING
 

package/tests/test_models/test_flowchart.py

@@ -1,7 +1,7 @@
 from functools import partial
 from pathlib import Path
 from textwrap import dedent
-from unittest.mock import call, patch
+from unittest.mock import Mock, call, patch
 
 import pytest
 from kedro.io import MemoryDataset
@@ -215,6 +215,46 @@ def test_create_parameters_node_single_parameter(
         assert parameters_node.parameter_value == 0.3
         assert parameters_node.modular_pipelines == expected_modular_pipelines
 
+    def test_create_single_parameter_with_complex_type(self):
+        parameters_dataset = MemoryDataset(data=object())
+        parameters_node = GraphNode.create_parameters_node(
+            dataset_id="params:test_split_ratio",
+            dataset_name="params:test_split_ratio",
+            layer=None,
+            tags=set(),
+            parameters=parameters_dataset,
+            modular_pipelines=set(),
+        )
+        assert isinstance(parameters_node, ParametersNode)
+        assert parameters_node.kedro_obj is parameters_dataset
+        assert not parameters_node.is_all_parameters()
+        assert parameters_node.is_single_parameter()
+        assert isinstance(parameters_node.parameter_value, str)
+
+    def test_create_all_parameters_with_complex_type(self):
+        mock_object = Mock()
+        parameters_dataset = MemoryDataset(
+            data={
+                "test_split_ratio": 0.3,
+                "num_epochs": 1000,
+                "complex_param": mock_object,
+            }
+        )
+        parameters_node = GraphNode.create_parameters_node(
+            dataset_id="parameters",
+            dataset_name="parameters",
+            layer=None,
+            tags=set(),
+            parameters=parameters_dataset,
+            modular_pipelines=set(),
+        )
+        assert isinstance(parameters_node, ParametersNode)
+        assert parameters_node.kedro_obj is parameters_dataset
+        assert parameters_node.id == "parameters"
+        assert parameters_node.is_all_parameters()
+        assert not parameters_node.is_single_parameter()
+        assert isinstance(parameters_node.parameter_value, str)
+
     def test_create_non_existing_parameter_node(self):
         """Test the case where ``parameters`` is equal to None"""
         parameters_node = GraphNode.create_parameters_node(